mbed-os 6.10 versione
cmsis_dsp/TransformFunctions/arm_cfft_radix4_q15.c@3:7a284390b0ce, 2013-11-08 (annotated)
- Committer:
- mbed_official
- Date:
- Fri Nov 08 13:45:10 2013 +0000
- Revision:
- 3:7a284390b0ce
- Parent:
- 2:da51fb522205
Synchronized with git revision e69956aba2f68a2a26ac26b051f8d349deaa1ce8
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
emilmont | 1:fdd22bb7aa52 | 1 | /* ---------------------------------------------------------------------- |
mbed_official | 3:7a284390b0ce | 2 | * Copyright (C) 2010-2013 ARM Limited. All rights reserved. |
emilmont | 1:fdd22bb7aa52 | 3 | * |
mbed_official | 3:7a284390b0ce | 4 | * $Date: 17. January 2013 |
mbed_official | 3:7a284390b0ce | 5 | * $Revision: V1.4.1 |
emilmont | 1:fdd22bb7aa52 | 6 | * |
emilmont | 2:da51fb522205 | 7 | * Project: CMSIS DSP Library |
emilmont | 2:da51fb522205 | 8 | * Title: arm_cfft_radix4_q15.c |
emilmont | 1:fdd22bb7aa52 | 9 | * |
emilmont | 2:da51fb522205 | 10 | * Description: This file has function definition of Radix-4 FFT & IFFT function and |
emilmont | 2:da51fb522205 | 11 | * In-place bit reversal using bit reversal table |
emilmont | 1:fdd22bb7aa52 | 12 | * |
emilmont | 1:fdd22bb7aa52 | 13 | * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 |
emilmont | 1:fdd22bb7aa52 | 14 | * |
mbed_official | 3:7a284390b0ce | 15 | * Redistribution and use in source and binary forms, with or without |
mbed_official | 3:7a284390b0ce | 16 | * modification, are permitted provided that the following conditions |
mbed_official | 3:7a284390b0ce | 17 | * are met: |
mbed_official | 3:7a284390b0ce | 18 | * - Redistributions of source code must retain the above copyright |
mbed_official | 3:7a284390b0ce | 19 | * notice, this list of conditions and the following disclaimer. |
mbed_official | 3:7a284390b0ce | 20 | * - Redistributions in binary form must reproduce the above copyright |
mbed_official | 3:7a284390b0ce | 21 | * notice, this list of conditions and the following disclaimer in |
mbed_official | 3:7a284390b0ce | 22 | * the documentation and/or other materials provided with the |
mbed_official | 3:7a284390b0ce | 23 | * distribution. |
mbed_official | 3:7a284390b0ce | 24 | * - Neither the name of ARM LIMITED nor the names of its contributors |
mbed_official | 3:7a284390b0ce | 25 | * may be used to endorse or promote products derived from this |
mbed_official | 3:7a284390b0ce | 26 | * software without specific prior written permission. |
mbed_official | 3:7a284390b0ce | 27 | * |
mbed_official | 3:7a284390b0ce | 28 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
mbed_official | 3:7a284390b0ce | 29 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
mbed_official | 3:7a284390b0ce | 30 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
mbed_official | 3:7a284390b0ce | 31 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
mbed_official | 3:7a284390b0ce | 32 | * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
mbed_official | 3:7a284390b0ce | 33 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
mbed_official | 3:7a284390b0ce | 34 | * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
mbed_official | 3:7a284390b0ce | 35 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
mbed_official | 3:7a284390b0ce | 36 | * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
mbed_official | 3:7a284390b0ce | 37 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
mbed_official | 3:7a284390b0ce | 38 | * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
mbed_official | 3:7a284390b0ce | 39 | * POSSIBILITY OF SUCH DAMAGE. |
emilmont | 1:fdd22bb7aa52 | 40 | * -------------------------------------------------------------------- */ |
emilmont | 1:fdd22bb7aa52 | 41 | |
emilmont | 1:fdd22bb7aa52 | 42 | #include "arm_math.h" |
emilmont | 1:fdd22bb7aa52 | 43 | |
mbed_official | 3:7a284390b0ce | 44 | |
mbed_official | 3:7a284390b0ce | 45 | void arm_radix4_butterfly_q15( |
mbed_official | 3:7a284390b0ce | 46 | q15_t * pSrc16, |
mbed_official | 3:7a284390b0ce | 47 | uint32_t fftLen, |
mbed_official | 3:7a284390b0ce | 48 | q15_t * pCoef16, |
mbed_official | 3:7a284390b0ce | 49 | uint32_t twidCoefModifier); |
mbed_official | 3:7a284390b0ce | 50 | |
mbed_official | 3:7a284390b0ce | 51 | void arm_radix4_butterfly_inverse_q15( |
mbed_official | 3:7a284390b0ce | 52 | q15_t * pSrc16, |
mbed_official | 3:7a284390b0ce | 53 | uint32_t fftLen, |
mbed_official | 3:7a284390b0ce | 54 | q15_t * pCoef16, |
mbed_official | 3:7a284390b0ce | 55 | uint32_t twidCoefModifier); |
mbed_official | 3:7a284390b0ce | 56 | |
mbed_official | 3:7a284390b0ce | 57 | void arm_bitreversal_q15( |
mbed_official | 3:7a284390b0ce | 58 | q15_t * pSrc, |
mbed_official | 3:7a284390b0ce | 59 | uint32_t fftLen, |
mbed_official | 3:7a284390b0ce | 60 | uint16_t bitRevFactor, |
mbed_official | 3:7a284390b0ce | 61 | uint16_t * pBitRevTab); |
mbed_official | 3:7a284390b0ce | 62 | |
emilmont | 1:fdd22bb7aa52 | 63 | /** |
emilmont | 1:fdd22bb7aa52 | 64 | * @ingroup groupTransforms |
emilmont | 1:fdd22bb7aa52 | 65 | */ |
emilmont | 1:fdd22bb7aa52 | 66 | |
emilmont | 1:fdd22bb7aa52 | 67 | /** |
mbed_official | 3:7a284390b0ce | 68 | * @addtogroup ComplexFFT |
emilmont | 1:fdd22bb7aa52 | 69 | * @{ |
emilmont | 1:fdd22bb7aa52 | 70 | */ |
emilmont | 1:fdd22bb7aa52 | 71 | |
emilmont | 1:fdd22bb7aa52 | 72 | |
emilmont | 1:fdd22bb7aa52 | 73 | /** |
emilmont | 1:fdd22bb7aa52 | 74 | * @details |
emilmont | 1:fdd22bb7aa52 | 75 | * @brief Processing function for the Q15 CFFT/CIFFT. |
emilmont | 1:fdd22bb7aa52 | 76 | * @param[in] *S points to an instance of the Q15 CFFT/CIFFT structure. |
emilmont | 1:fdd22bb7aa52 | 77 | * @param[in, out] *pSrc points to the complex data buffer. Processing occurs in-place. |
emilmont | 1:fdd22bb7aa52 | 78 | * @return none. |
emilmont | 1:fdd22bb7aa52 | 79 | * |
emilmont | 1:fdd22bb7aa52 | 80 | * \par Input and output formats: |
emilmont | 1:fdd22bb7aa52 | 81 | * \par |
emilmont | 1:fdd22bb7aa52 | 82 | * Internally input is downscaled by 2 for every stage to avoid saturations inside CFFT/CIFFT process. |
emilmont | 1:fdd22bb7aa52 | 83 | * Hence the output format is different for different FFT sizes. |
emilmont | 1:fdd22bb7aa52 | 84 | * The input and output formats for different FFT sizes and number of bits to upscale are mentioned in the tables below for CFFT and CIFFT: |
emilmont | 1:fdd22bb7aa52 | 85 | * \par |
emilmont | 1:fdd22bb7aa52 | 86 | * \image html CFFTQ15.gif "Input and Output Formats for Q15 CFFT" |
emilmont | 1:fdd22bb7aa52 | 87 | * \image html CIFFTQ15.gif "Input and Output Formats for Q15 CIFFT" |
emilmont | 1:fdd22bb7aa52 | 88 | */ |
emilmont | 1:fdd22bb7aa52 | 89 | |
emilmont | 1:fdd22bb7aa52 | 90 | void arm_cfft_radix4_q15( |
emilmont | 1:fdd22bb7aa52 | 91 | const arm_cfft_radix4_instance_q15 * S, |
emilmont | 1:fdd22bb7aa52 | 92 | q15_t * pSrc) |
emilmont | 1:fdd22bb7aa52 | 93 | { |
emilmont | 1:fdd22bb7aa52 | 94 | if(S->ifftFlag == 1u) |
emilmont | 1:fdd22bb7aa52 | 95 | { |
emilmont | 1:fdd22bb7aa52 | 96 | /* Complex IFFT radix-4 */ |
emilmont | 1:fdd22bb7aa52 | 97 | arm_radix4_butterfly_inverse_q15(pSrc, S->fftLen, S->pTwiddle, |
emilmont | 1:fdd22bb7aa52 | 98 | S->twidCoefModifier); |
emilmont | 1:fdd22bb7aa52 | 99 | } |
emilmont | 1:fdd22bb7aa52 | 100 | else |
emilmont | 1:fdd22bb7aa52 | 101 | { |
emilmont | 1:fdd22bb7aa52 | 102 | /* Complex FFT radix-4 */ |
emilmont | 1:fdd22bb7aa52 | 103 | arm_radix4_butterfly_q15(pSrc, S->fftLen, S->pTwiddle, |
emilmont | 1:fdd22bb7aa52 | 104 | S->twidCoefModifier); |
emilmont | 1:fdd22bb7aa52 | 105 | } |
emilmont | 1:fdd22bb7aa52 | 106 | |
emilmont | 1:fdd22bb7aa52 | 107 | if(S->bitReverseFlag == 1u) |
emilmont | 1:fdd22bb7aa52 | 108 | { |
emilmont | 1:fdd22bb7aa52 | 109 | /* Bit Reversal */ |
emilmont | 1:fdd22bb7aa52 | 110 | arm_bitreversal_q15(pSrc, S->fftLen, S->bitRevFactor, S->pBitRevTable); |
emilmont | 1:fdd22bb7aa52 | 111 | } |
emilmont | 1:fdd22bb7aa52 | 112 | |
emilmont | 1:fdd22bb7aa52 | 113 | } |
emilmont | 1:fdd22bb7aa52 | 114 | |
emilmont | 1:fdd22bb7aa52 | 115 | /** |
mbed_official | 3:7a284390b0ce | 116 | * @} end of ComplexFFT group |
emilmont | 1:fdd22bb7aa52 | 117 | */ |
emilmont | 1:fdd22bb7aa52 | 118 | |
emilmont | 1:fdd22bb7aa52 | 119 | /* |
emilmont | 1:fdd22bb7aa52 | 120 | * Radix-4 FFT algorithm used is : |
emilmont | 1:fdd22bb7aa52 | 121 | * |
emilmont | 1:fdd22bb7aa52 | 122 | * Input real and imaginary data: |
emilmont | 1:fdd22bb7aa52 | 123 | * x(n) = xa + j * ya |
emilmont | 1:fdd22bb7aa52 | 124 | * x(n+N/4 ) = xb + j * yb |
emilmont | 1:fdd22bb7aa52 | 125 | * x(n+N/2 ) = xc + j * yc |
emilmont | 1:fdd22bb7aa52 | 126 | * x(n+3N 4) = xd + j * yd |
emilmont | 1:fdd22bb7aa52 | 127 | * |
emilmont | 1:fdd22bb7aa52 | 128 | * |
emilmont | 1:fdd22bb7aa52 | 129 | * Output real and imaginary data: |
emilmont | 1:fdd22bb7aa52 | 130 | * x(4r) = xa'+ j * ya' |
emilmont | 1:fdd22bb7aa52 | 131 | * x(4r+1) = xb'+ j * yb' |
emilmont | 1:fdd22bb7aa52 | 132 | * x(4r+2) = xc'+ j * yc' |
emilmont | 1:fdd22bb7aa52 | 133 | * x(4r+3) = xd'+ j * yd' |
emilmont | 1:fdd22bb7aa52 | 134 | * |
emilmont | 1:fdd22bb7aa52 | 135 | * |
emilmont | 1:fdd22bb7aa52 | 136 | * Twiddle factors for radix-4 FFT: |
emilmont | 1:fdd22bb7aa52 | 137 | * Wn = co1 + j * (- si1) |
emilmont | 1:fdd22bb7aa52 | 138 | * W2n = co2 + j * (- si2) |
emilmont | 1:fdd22bb7aa52 | 139 | * W3n = co3 + j * (- si3) |
emilmont | 1:fdd22bb7aa52 | 140 | |
emilmont | 1:fdd22bb7aa52 | 141 | * The real and imaginary output values for the radix-4 butterfly are |
emilmont | 1:fdd22bb7aa52 | 142 | * xa' = xa + xb + xc + xd |
emilmont | 1:fdd22bb7aa52 | 143 | * ya' = ya + yb + yc + yd |
emilmont | 1:fdd22bb7aa52 | 144 | * xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) |
emilmont | 1:fdd22bb7aa52 | 145 | * yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) |
emilmont | 1:fdd22bb7aa52 | 146 | * xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) |
emilmont | 1:fdd22bb7aa52 | 147 | * yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) |
emilmont | 1:fdd22bb7aa52 | 148 | * xd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) |
emilmont | 1:fdd22bb7aa52 | 149 | * yd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) |
emilmont | 1:fdd22bb7aa52 | 150 | * |
emilmont | 1:fdd22bb7aa52 | 151 | */ |
emilmont | 1:fdd22bb7aa52 | 152 | |
emilmont | 1:fdd22bb7aa52 | 153 | /** |
emilmont | 1:fdd22bb7aa52 | 154 | * @brief Core function for the Q15 CFFT butterfly process. |
emilmont | 1:fdd22bb7aa52 | 155 | * @param[in, out] *pSrc16 points to the in-place buffer of Q15 data type. |
emilmont | 1:fdd22bb7aa52 | 156 | * @param[in] fftLen length of the FFT. |
emilmont | 1:fdd22bb7aa52 | 157 | * @param[in] *pCoef16 points to twiddle coefficient buffer. |
emilmont | 1:fdd22bb7aa52 | 158 | * @param[in] twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table. |
emilmont | 1:fdd22bb7aa52 | 159 | * @return none. |
emilmont | 1:fdd22bb7aa52 | 160 | */ |
emilmont | 1:fdd22bb7aa52 | 161 | |
emilmont | 1:fdd22bb7aa52 | 162 | void arm_radix4_butterfly_q15( |
emilmont | 1:fdd22bb7aa52 | 163 | q15_t * pSrc16, |
emilmont | 1:fdd22bb7aa52 | 164 | uint32_t fftLen, |
emilmont | 1:fdd22bb7aa52 | 165 | q15_t * pCoef16, |
emilmont | 1:fdd22bb7aa52 | 166 | uint32_t twidCoefModifier) |
emilmont | 1:fdd22bb7aa52 | 167 | { |
emilmont | 1:fdd22bb7aa52 | 168 | |
mbed_official | 3:7a284390b0ce | 169 | #ifndef ARM_MATH_CM0_FAMILY |
emilmont | 1:fdd22bb7aa52 | 170 | |
emilmont | 1:fdd22bb7aa52 | 171 | /* Run the below code for Cortex-M4 and Cortex-M3 */ |
emilmont | 1:fdd22bb7aa52 | 172 | |
emilmont | 1:fdd22bb7aa52 | 173 | q31_t R, S, T, U; |
emilmont | 1:fdd22bb7aa52 | 174 | q31_t C1, C2, C3, out1, out2; |
emilmont | 1:fdd22bb7aa52 | 175 | uint32_t n1, n2, ic, i0, i1, i2, i3, j, k; |
emilmont | 1:fdd22bb7aa52 | 176 | q15_t in; |
emilmont | 1:fdd22bb7aa52 | 177 | |
emilmont | 1:fdd22bb7aa52 | 178 | q15_t *ptr1; |
emilmont | 1:fdd22bb7aa52 | 179 | |
emilmont | 1:fdd22bb7aa52 | 180 | |
emilmont | 1:fdd22bb7aa52 | 181 | |
emilmont | 1:fdd22bb7aa52 | 182 | q31_t xaya, xbyb, xcyc, xdyd; |
emilmont | 1:fdd22bb7aa52 | 183 | |
emilmont | 1:fdd22bb7aa52 | 184 | /* Total process is divided into three stages */ |
emilmont | 1:fdd22bb7aa52 | 185 | |
emilmont | 1:fdd22bb7aa52 | 186 | /* process first stage, middle stages, & last stage */ |
emilmont | 1:fdd22bb7aa52 | 187 | |
emilmont | 1:fdd22bb7aa52 | 188 | /* Initializations for the first stage */ |
emilmont | 1:fdd22bb7aa52 | 189 | n2 = fftLen; |
emilmont | 1:fdd22bb7aa52 | 190 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 191 | |
emilmont | 1:fdd22bb7aa52 | 192 | /* n2 = fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 193 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 194 | |
emilmont | 1:fdd22bb7aa52 | 195 | /* Index for twiddle coefficient */ |
emilmont | 1:fdd22bb7aa52 | 196 | ic = 0u; |
emilmont | 1:fdd22bb7aa52 | 197 | |
emilmont | 1:fdd22bb7aa52 | 198 | /* Index for input read and output write */ |
emilmont | 1:fdd22bb7aa52 | 199 | i0 = 0u; |
emilmont | 1:fdd22bb7aa52 | 200 | j = n2; |
emilmont | 1:fdd22bb7aa52 | 201 | |
emilmont | 1:fdd22bb7aa52 | 202 | /* Input is in 1.15(q15) format */ |
emilmont | 1:fdd22bb7aa52 | 203 | |
emilmont | 1:fdd22bb7aa52 | 204 | /* start of first stage process */ |
emilmont | 1:fdd22bb7aa52 | 205 | do |
emilmont | 1:fdd22bb7aa52 | 206 | { |
emilmont | 1:fdd22bb7aa52 | 207 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 208 | |
emilmont | 1:fdd22bb7aa52 | 209 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 210 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 211 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 212 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 213 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 214 | |
emilmont | 1:fdd22bb7aa52 | 215 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 216 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 217 | T = _SIMD32_OFFSET(pSrc16 + (2u * i0)); |
emilmont | 1:fdd22bb7aa52 | 218 | in = ((int16_t) (T & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 219 | T = ((T >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 220 | |
emilmont | 1:fdd22bb7aa52 | 221 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 222 | S = _SIMD32_OFFSET(pSrc16 + (2u * i2)); |
emilmont | 1:fdd22bb7aa52 | 223 | in = ((int16_t) (S & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 224 | S = ((S >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 225 | |
emilmont | 1:fdd22bb7aa52 | 226 | /* R = packed((ya + yc), (xa + xc) ) */ |
emilmont | 1:fdd22bb7aa52 | 227 | R = __QADD16(T, S); |
emilmont | 1:fdd22bb7aa52 | 228 | |
emilmont | 1:fdd22bb7aa52 | 229 | /* S = packed((ya - yc), (xa - xc) ) */ |
emilmont | 1:fdd22bb7aa52 | 230 | S = __QSUB16(T, S); |
emilmont | 1:fdd22bb7aa52 | 231 | |
emilmont | 1:fdd22bb7aa52 | 232 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 233 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 234 | T = _SIMD32_OFFSET(pSrc16 + (2u * i1)); |
emilmont | 1:fdd22bb7aa52 | 235 | in = ((int16_t) (T & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 236 | T = ((T >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 237 | |
emilmont | 1:fdd22bb7aa52 | 238 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 239 | U = _SIMD32_OFFSET(pSrc16 + (2u * i3)); |
emilmont | 1:fdd22bb7aa52 | 240 | in = ((int16_t) (U & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 241 | U = ((U >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 242 | |
emilmont | 1:fdd22bb7aa52 | 243 | /* T = packed((yb + yd), (xb + xd) ) */ |
emilmont | 1:fdd22bb7aa52 | 244 | T = __QADD16(T, U); |
emilmont | 1:fdd22bb7aa52 | 245 | |
emilmont | 1:fdd22bb7aa52 | 246 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 247 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 248 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 249 | _SIMD32_OFFSET(pSrc16 + (2u * i0)) = __SHADD16(R, T); |
emilmont | 1:fdd22bb7aa52 | 250 | |
emilmont | 1:fdd22bb7aa52 | 251 | /* R = packed((ya + yc) - (yb + yd), (xa + xc)- (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 252 | R = __QSUB16(R, T); |
emilmont | 1:fdd22bb7aa52 | 253 | |
emilmont | 1:fdd22bb7aa52 | 254 | /* co2 & si2 are read from SIMD Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 255 | C2 = _SIMD32_OFFSET(pCoef16 + (4u * ic)); |
emilmont | 1:fdd22bb7aa52 | 256 | |
emilmont | 1:fdd22bb7aa52 | 257 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 258 | |
emilmont | 1:fdd22bb7aa52 | 259 | /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 260 | out1 = __SMUAD(C2, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 261 | /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 262 | out2 = __SMUSDX(C2, R); |
emilmont | 1:fdd22bb7aa52 | 263 | |
emilmont | 1:fdd22bb7aa52 | 264 | #else |
emilmont | 1:fdd22bb7aa52 | 265 | |
emilmont | 1:fdd22bb7aa52 | 266 | /* xc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 267 | out1 = __SMUSDX(R, C2) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 268 | /* yc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 269 | out2 = __SMUAD(C2, R); |
emilmont | 1:fdd22bb7aa52 | 270 | |
emilmont | 1:fdd22bb7aa52 | 271 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 272 | |
emilmont | 1:fdd22bb7aa52 | 273 | /* Reading i0+fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 274 | /* T = packed(yb, xb) */ |
emilmont | 1:fdd22bb7aa52 | 275 | T = _SIMD32_OFFSET(pSrc16 + (2u * i1)); |
emilmont | 1:fdd22bb7aa52 | 276 | in = ((int16_t) (T & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 277 | T = ((T >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 278 | |
emilmont | 1:fdd22bb7aa52 | 279 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 280 | /* writing output(xc', yc') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 281 | _SIMD32_OFFSET(pSrc16 + (2u * i1)) = |
emilmont | 1:fdd22bb7aa52 | 282 | (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 283 | |
emilmont | 1:fdd22bb7aa52 | 284 | /* Butterfly calculations */ |
emilmont | 1:fdd22bb7aa52 | 285 | /* U = packed(yd, xd) */ |
emilmont | 1:fdd22bb7aa52 | 286 | U = _SIMD32_OFFSET(pSrc16 + (2u * i3)); |
emilmont | 1:fdd22bb7aa52 | 287 | in = ((int16_t) (U & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 288 | U = ((U >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 289 | |
emilmont | 1:fdd22bb7aa52 | 290 | /* T = packed(yb-yd, xb-xd) */ |
emilmont | 1:fdd22bb7aa52 | 291 | T = __QSUB16(T, U); |
emilmont | 1:fdd22bb7aa52 | 292 | |
emilmont | 1:fdd22bb7aa52 | 293 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 294 | |
emilmont | 1:fdd22bb7aa52 | 295 | /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 296 | R = __QASX(S, T); |
emilmont | 1:fdd22bb7aa52 | 297 | /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 298 | S = __QSAX(S, T); |
emilmont | 1:fdd22bb7aa52 | 299 | |
emilmont | 1:fdd22bb7aa52 | 300 | #else |
emilmont | 1:fdd22bb7aa52 | 301 | |
emilmont | 1:fdd22bb7aa52 | 302 | /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 303 | R = __QSAX(S, T); |
emilmont | 1:fdd22bb7aa52 | 304 | /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 305 | S = __QASX(S, T); |
emilmont | 1:fdd22bb7aa52 | 306 | |
emilmont | 1:fdd22bb7aa52 | 307 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 308 | |
emilmont | 1:fdd22bb7aa52 | 309 | /* co1 & si1 are read from SIMD Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 310 | C1 = _SIMD32_OFFSET(pCoef16 + (2u * ic)); |
emilmont | 1:fdd22bb7aa52 | 311 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 312 | |
emilmont | 1:fdd22bb7aa52 | 313 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 314 | |
emilmont | 1:fdd22bb7aa52 | 315 | /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 316 | out1 = __SMUAD(C1, S) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 317 | /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 318 | out2 = __SMUSDX(C1, S); |
emilmont | 1:fdd22bb7aa52 | 319 | |
emilmont | 1:fdd22bb7aa52 | 320 | #else |
emilmont | 1:fdd22bb7aa52 | 321 | |
emilmont | 1:fdd22bb7aa52 | 322 | /* xb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 323 | out1 = __SMUSDX(S, C1) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 324 | /* yb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 325 | out2 = __SMUAD(C1, S); |
emilmont | 1:fdd22bb7aa52 | 326 | |
emilmont | 1:fdd22bb7aa52 | 327 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 328 | |
emilmont | 1:fdd22bb7aa52 | 329 | /* writing output(xb', yb') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 330 | _SIMD32_OFFSET(pSrc16 + (2u * i2)) = |
emilmont | 1:fdd22bb7aa52 | 331 | ((out2) & 0xFFFF0000) | ((out1) & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 332 | |
emilmont | 1:fdd22bb7aa52 | 333 | |
emilmont | 1:fdd22bb7aa52 | 334 | /* co3 & si3 are read from SIMD Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 335 | C3 = _SIMD32_OFFSET(pCoef16 + (6u * ic)); |
emilmont | 1:fdd22bb7aa52 | 336 | /* Butterfly process for the i0+3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 337 | |
emilmont | 1:fdd22bb7aa52 | 338 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 339 | |
emilmont | 1:fdd22bb7aa52 | 340 | /* xd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 341 | out1 = __SMUAD(C3, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 342 | /* yd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 343 | out2 = __SMUSDX(C3, R); |
emilmont | 1:fdd22bb7aa52 | 344 | |
emilmont | 1:fdd22bb7aa52 | 345 | #else |
emilmont | 1:fdd22bb7aa52 | 346 | |
emilmont | 1:fdd22bb7aa52 | 347 | /* xd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 348 | out1 = __SMUSDX(R, C3) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 349 | /* yd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 350 | out2 = __SMUAD(C3, R); |
emilmont | 1:fdd22bb7aa52 | 351 | |
emilmont | 1:fdd22bb7aa52 | 352 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 353 | |
emilmont | 1:fdd22bb7aa52 | 354 | /* writing output(xd', yd') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 355 | _SIMD32_OFFSET(pSrc16 + (2u * i3)) = |
emilmont | 1:fdd22bb7aa52 | 356 | ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 357 | |
emilmont | 1:fdd22bb7aa52 | 358 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 359 | ic = ic + twidCoefModifier; |
emilmont | 1:fdd22bb7aa52 | 360 | |
emilmont | 1:fdd22bb7aa52 | 361 | /* Updating input index */ |
emilmont | 1:fdd22bb7aa52 | 362 | i0 = i0 + 1u; |
emilmont | 1:fdd22bb7aa52 | 363 | |
emilmont | 1:fdd22bb7aa52 | 364 | } while(--j); |
emilmont | 1:fdd22bb7aa52 | 365 | /* data is in 4.11(q11) format */ |
emilmont | 1:fdd22bb7aa52 | 366 | |
emilmont | 1:fdd22bb7aa52 | 367 | /* end of first stage process */ |
emilmont | 1:fdd22bb7aa52 | 368 | |
emilmont | 1:fdd22bb7aa52 | 369 | |
emilmont | 1:fdd22bb7aa52 | 370 | /* start of middle stage process */ |
emilmont | 1:fdd22bb7aa52 | 371 | |
emilmont | 1:fdd22bb7aa52 | 372 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 373 | twidCoefModifier <<= 2u; |
emilmont | 1:fdd22bb7aa52 | 374 | |
emilmont | 1:fdd22bb7aa52 | 375 | /* Calculation of Middle stage */ |
emilmont | 1:fdd22bb7aa52 | 376 | for (k = fftLen / 4u; k > 4u; k >>= 2u) |
emilmont | 1:fdd22bb7aa52 | 377 | { |
emilmont | 1:fdd22bb7aa52 | 378 | /* Initializations for the middle stage */ |
emilmont | 1:fdd22bb7aa52 | 379 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 380 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 381 | ic = 0u; |
emilmont | 1:fdd22bb7aa52 | 382 | |
emilmont | 1:fdd22bb7aa52 | 383 | for (j = 0u; j <= (n2 - 1u); j++) |
emilmont | 1:fdd22bb7aa52 | 384 | { |
emilmont | 1:fdd22bb7aa52 | 385 | /* index calculation for the coefficients */ |
emilmont | 1:fdd22bb7aa52 | 386 | C1 = _SIMD32_OFFSET(pCoef16 + (2u * ic)); |
emilmont | 1:fdd22bb7aa52 | 387 | C2 = _SIMD32_OFFSET(pCoef16 + (4u * ic)); |
emilmont | 1:fdd22bb7aa52 | 388 | C3 = _SIMD32_OFFSET(pCoef16 + (6u * ic)); |
emilmont | 1:fdd22bb7aa52 | 389 | |
emilmont | 1:fdd22bb7aa52 | 390 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 391 | ic = ic + twidCoefModifier; |
emilmont | 1:fdd22bb7aa52 | 392 | |
emilmont | 1:fdd22bb7aa52 | 393 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 394 | for (i0 = j; i0 < fftLen; i0 += n1) |
emilmont | 1:fdd22bb7aa52 | 395 | { |
emilmont | 1:fdd22bb7aa52 | 396 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 397 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 398 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 399 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 400 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 401 | |
emilmont | 1:fdd22bb7aa52 | 402 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 403 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 404 | T = _SIMD32_OFFSET(pSrc16 + (2u * i0)); |
emilmont | 1:fdd22bb7aa52 | 405 | |
emilmont | 1:fdd22bb7aa52 | 406 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 407 | S = _SIMD32_OFFSET(pSrc16 + (2u * i2)); |
emilmont | 1:fdd22bb7aa52 | 408 | |
emilmont | 1:fdd22bb7aa52 | 409 | /* R = packed( (ya + yc), (xa + xc)) */ |
emilmont | 1:fdd22bb7aa52 | 410 | R = __QADD16(T, S); |
emilmont | 1:fdd22bb7aa52 | 411 | |
emilmont | 1:fdd22bb7aa52 | 412 | /* S = packed((ya - yc), (xa - xc)) */ |
emilmont | 1:fdd22bb7aa52 | 413 | S = __QSUB16(T, S); |
emilmont | 1:fdd22bb7aa52 | 414 | |
emilmont | 1:fdd22bb7aa52 | 415 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 416 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 417 | T = _SIMD32_OFFSET(pSrc16 + (2u * i1)); |
emilmont | 1:fdd22bb7aa52 | 418 | |
emilmont | 1:fdd22bb7aa52 | 419 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 420 | U = _SIMD32_OFFSET(pSrc16 + (2u * i3)); |
emilmont | 1:fdd22bb7aa52 | 421 | |
emilmont | 1:fdd22bb7aa52 | 422 | /* T = packed( (yb + yd), (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 423 | T = __QADD16(T, U); |
emilmont | 1:fdd22bb7aa52 | 424 | |
emilmont | 1:fdd22bb7aa52 | 425 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 426 | |
emilmont | 1:fdd22bb7aa52 | 427 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 428 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 429 | out1 = __SHADD16(R, T); |
emilmont | 1:fdd22bb7aa52 | 430 | in = ((int16_t) (out1 & 0xFFFF)) >> 1; |
emilmont | 1:fdd22bb7aa52 | 431 | out1 = ((out1 >> 1) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 432 | _SIMD32_OFFSET(pSrc16 + (2u * i0)) = out1; |
emilmont | 1:fdd22bb7aa52 | 433 | |
emilmont | 1:fdd22bb7aa52 | 434 | /* R = packed( (ya + yc) - (yb + yd), (xa + xc) - (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 435 | R = __SHSUB16(R, T); |
emilmont | 1:fdd22bb7aa52 | 436 | |
emilmont | 1:fdd22bb7aa52 | 437 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 438 | |
emilmont | 1:fdd22bb7aa52 | 439 | /* (ya-yb+yc-yd)* (si2) + (xa-xb+xc-xd)* co2 */ |
emilmont | 1:fdd22bb7aa52 | 440 | out1 = __SMUAD(C2, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 441 | |
emilmont | 1:fdd22bb7aa52 | 442 | /* (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 443 | out2 = __SMUSDX(C2, R); |
emilmont | 1:fdd22bb7aa52 | 444 | |
emilmont | 1:fdd22bb7aa52 | 445 | #else |
emilmont | 1:fdd22bb7aa52 | 446 | |
emilmont | 1:fdd22bb7aa52 | 447 | /* (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 448 | out1 = __SMUSDX(R, C2) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 449 | |
emilmont | 1:fdd22bb7aa52 | 450 | /* (ya-yb+yc-yd)* (si2) + (xa-xb+xc-xd)* co2 */ |
emilmont | 1:fdd22bb7aa52 | 451 | out2 = __SMUAD(C2, R); |
emilmont | 1:fdd22bb7aa52 | 452 | |
emilmont | 1:fdd22bb7aa52 | 453 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 454 | |
emilmont | 1:fdd22bb7aa52 | 455 | /* Reading i0+3fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 456 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 457 | T = _SIMD32_OFFSET(pSrc16 + (2u * i1)); |
emilmont | 1:fdd22bb7aa52 | 458 | |
emilmont | 1:fdd22bb7aa52 | 459 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 460 | /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 461 | /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 462 | _SIMD32_OFFSET(pSrc16 + (2u * i1)) = |
emilmont | 1:fdd22bb7aa52 | 463 | ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 464 | |
emilmont | 1:fdd22bb7aa52 | 465 | /* Butterfly calculations */ |
emilmont | 1:fdd22bb7aa52 | 466 | |
emilmont | 1:fdd22bb7aa52 | 467 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 468 | U = _SIMD32_OFFSET(pSrc16 + (2u * i3)); |
emilmont | 1:fdd22bb7aa52 | 469 | |
emilmont | 1:fdd22bb7aa52 | 470 | /* T = packed(yb-yd, xb-xd) */ |
emilmont | 1:fdd22bb7aa52 | 471 | T = __QSUB16(T, U); |
emilmont | 1:fdd22bb7aa52 | 472 | |
emilmont | 1:fdd22bb7aa52 | 473 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 474 | |
emilmont | 1:fdd22bb7aa52 | 475 | /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 476 | R = __SHASX(S, T); |
emilmont | 1:fdd22bb7aa52 | 477 | |
emilmont | 1:fdd22bb7aa52 | 478 | /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 479 | S = __SHSAX(S, T); |
emilmont | 1:fdd22bb7aa52 | 480 | |
emilmont | 1:fdd22bb7aa52 | 481 | |
emilmont | 1:fdd22bb7aa52 | 482 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 483 | out1 = __SMUAD(C1, S) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 484 | out2 = __SMUSDX(C1, S); |
emilmont | 1:fdd22bb7aa52 | 485 | |
emilmont | 1:fdd22bb7aa52 | 486 | #else |
emilmont | 1:fdd22bb7aa52 | 487 | |
emilmont | 1:fdd22bb7aa52 | 488 | /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 489 | R = __SHSAX(S, T); |
emilmont | 1:fdd22bb7aa52 | 490 | |
emilmont | 1:fdd22bb7aa52 | 491 | /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 492 | S = __SHASX(S, T); |
emilmont | 1:fdd22bb7aa52 | 493 | |
emilmont | 1:fdd22bb7aa52 | 494 | |
emilmont | 1:fdd22bb7aa52 | 495 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 496 | out1 = __SMUSDX(S, C1) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 497 | out2 = __SMUAD(C1, S); |
emilmont | 1:fdd22bb7aa52 | 498 | |
emilmont | 1:fdd22bb7aa52 | 499 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 500 | |
emilmont | 1:fdd22bb7aa52 | 501 | /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 502 | /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 503 | _SIMD32_OFFSET(pSrc16 + (2u * i2)) = |
emilmont | 1:fdd22bb7aa52 | 504 | ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 505 | |
emilmont | 1:fdd22bb7aa52 | 506 | /* Butterfly process for the i0+3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 507 | |
emilmont | 1:fdd22bb7aa52 | 508 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 509 | |
emilmont | 1:fdd22bb7aa52 | 510 | out1 = __SMUAD(C3, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 511 | out2 = __SMUSDX(C3, R); |
emilmont | 1:fdd22bb7aa52 | 512 | |
emilmont | 1:fdd22bb7aa52 | 513 | #else |
emilmont | 1:fdd22bb7aa52 | 514 | |
emilmont | 1:fdd22bb7aa52 | 515 | out1 = __SMUSDX(R, C3) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 516 | out2 = __SMUAD(C3, R); |
emilmont | 1:fdd22bb7aa52 | 517 | |
emilmont | 1:fdd22bb7aa52 | 518 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 519 | |
emilmont | 1:fdd22bb7aa52 | 520 | /* xd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 521 | /* yd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 522 | _SIMD32_OFFSET(pSrc16 + (2u * i3)) = |
emilmont | 1:fdd22bb7aa52 | 523 | ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 524 | } |
emilmont | 1:fdd22bb7aa52 | 525 | } |
emilmont | 1:fdd22bb7aa52 | 526 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 527 | twidCoefModifier <<= 2u; |
emilmont | 1:fdd22bb7aa52 | 528 | } |
emilmont | 1:fdd22bb7aa52 | 529 | /* end of middle stage process */ |
emilmont | 1:fdd22bb7aa52 | 530 | |
emilmont | 1:fdd22bb7aa52 | 531 | |
emilmont | 1:fdd22bb7aa52 | 532 | /* data is in 10.6(q6) format for the 1024 point */ |
emilmont | 1:fdd22bb7aa52 | 533 | /* data is in 8.8(q8) format for the 256 point */ |
emilmont | 1:fdd22bb7aa52 | 534 | /* data is in 6.10(q10) format for the 64 point */ |
emilmont | 1:fdd22bb7aa52 | 535 | /* data is in 4.12(q12) format for the 16 point */ |
emilmont | 1:fdd22bb7aa52 | 536 | |
emilmont | 1:fdd22bb7aa52 | 537 | /* Initializations for the last stage */ |
emilmont | 1:fdd22bb7aa52 | 538 | j = fftLen >> 2; |
emilmont | 1:fdd22bb7aa52 | 539 | |
emilmont | 1:fdd22bb7aa52 | 540 | ptr1 = &pSrc16[0]; |
emilmont | 1:fdd22bb7aa52 | 541 | |
emilmont | 1:fdd22bb7aa52 | 542 | /* start of last stage process */ |
emilmont | 1:fdd22bb7aa52 | 543 | |
emilmont | 1:fdd22bb7aa52 | 544 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 545 | do |
emilmont | 1:fdd22bb7aa52 | 546 | { |
emilmont | 1:fdd22bb7aa52 | 547 | /* Read xa (real), ya(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 548 | xaya = *__SIMD32(ptr1)++; |
emilmont | 1:fdd22bb7aa52 | 549 | |
emilmont | 1:fdd22bb7aa52 | 550 | /* Read xb (real), yb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 551 | xbyb = *__SIMD32(ptr1)++; |
emilmont | 1:fdd22bb7aa52 | 552 | |
emilmont | 1:fdd22bb7aa52 | 553 | /* Read xc (real), yc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 554 | xcyc = *__SIMD32(ptr1)++; |
emilmont | 1:fdd22bb7aa52 | 555 | |
emilmont | 1:fdd22bb7aa52 | 556 | /* Read xd (real), yd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 557 | xdyd = *__SIMD32(ptr1)++; |
emilmont | 1:fdd22bb7aa52 | 558 | |
emilmont | 1:fdd22bb7aa52 | 559 | /* R = packed((ya + yc), (xa + xc)) */ |
emilmont | 1:fdd22bb7aa52 | 560 | R = __QADD16(xaya, xcyc); |
emilmont | 1:fdd22bb7aa52 | 561 | |
emilmont | 1:fdd22bb7aa52 | 562 | /* T = packed((yb + yd), (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 563 | T = __QADD16(xbyb, xdyd); |
emilmont | 1:fdd22bb7aa52 | 564 | |
emilmont | 1:fdd22bb7aa52 | 565 | /* pointer updation for writing */ |
emilmont | 1:fdd22bb7aa52 | 566 | ptr1 = ptr1 - 8u; |
emilmont | 1:fdd22bb7aa52 | 567 | |
emilmont | 1:fdd22bb7aa52 | 568 | |
emilmont | 1:fdd22bb7aa52 | 569 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 570 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 571 | *__SIMD32(ptr1)++ = __SHADD16(R, T); |
emilmont | 1:fdd22bb7aa52 | 572 | |
emilmont | 1:fdd22bb7aa52 | 573 | /* T = packed((yb + yd), (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 574 | T = __QADD16(xbyb, xdyd); |
emilmont | 1:fdd22bb7aa52 | 575 | |
emilmont | 1:fdd22bb7aa52 | 576 | /* xc' = (xa-xb+xc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 577 | /* yc' = (ya-yb+yc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 578 | *__SIMD32(ptr1)++ = __SHSUB16(R, T); |
emilmont | 1:fdd22bb7aa52 | 579 | |
emilmont | 1:fdd22bb7aa52 | 580 | /* S = packed((ya - yc), (xa - xc)) */ |
emilmont | 1:fdd22bb7aa52 | 581 | S = __QSUB16(xaya, xcyc); |
emilmont | 1:fdd22bb7aa52 | 582 | |
emilmont | 1:fdd22bb7aa52 | 583 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 584 | /* T = packed( (yb - yd), (xb - xd)) */ |
emilmont | 1:fdd22bb7aa52 | 585 | U = __QSUB16(xbyb, xdyd); |
emilmont | 1:fdd22bb7aa52 | 586 | |
emilmont | 1:fdd22bb7aa52 | 587 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 588 | |
emilmont | 1:fdd22bb7aa52 | 589 | /* xb' = (xa+yb-xc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 590 | /* yb' = (ya-xb-yc+xd) */ |
emilmont | 1:fdd22bb7aa52 | 591 | *__SIMD32(ptr1)++ = __SHSAX(S, U); |
emilmont | 1:fdd22bb7aa52 | 592 | |
emilmont | 1:fdd22bb7aa52 | 593 | |
emilmont | 1:fdd22bb7aa52 | 594 | /* xd' = (xa-yb-xc+yd) */ |
emilmont | 1:fdd22bb7aa52 | 595 | /* yd' = (ya+xb-yc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 596 | *__SIMD32(ptr1)++ = __SHASX(S, U); |
emilmont | 1:fdd22bb7aa52 | 597 | |
emilmont | 1:fdd22bb7aa52 | 598 | #else |
emilmont | 1:fdd22bb7aa52 | 599 | |
emilmont | 1:fdd22bb7aa52 | 600 | /* xb' = (xa+yb-xc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 601 | /* yb' = (ya-xb-yc+xd) */ |
emilmont | 1:fdd22bb7aa52 | 602 | *__SIMD32(ptr1)++ = __SHASX(S, U); |
emilmont | 1:fdd22bb7aa52 | 603 | |
emilmont | 1:fdd22bb7aa52 | 604 | |
emilmont | 1:fdd22bb7aa52 | 605 | /* xd' = (xa-yb-xc+yd) */ |
emilmont | 1:fdd22bb7aa52 | 606 | /* yd' = (ya+xb-yc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 607 | *__SIMD32(ptr1)++ = __SHSAX(S, U); |
emilmont | 1:fdd22bb7aa52 | 608 | |
emilmont | 1:fdd22bb7aa52 | 609 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 610 | |
emilmont | 1:fdd22bb7aa52 | 611 | } while(--j); |
emilmont | 1:fdd22bb7aa52 | 612 | |
emilmont | 1:fdd22bb7aa52 | 613 | /* end of last stage process */ |
emilmont | 1:fdd22bb7aa52 | 614 | |
emilmont | 1:fdd22bb7aa52 | 615 | /* output is in 11.5(q5) format for the 1024 point */ |
emilmont | 1:fdd22bb7aa52 | 616 | /* output is in 9.7(q7) format for the 256 point */ |
emilmont | 1:fdd22bb7aa52 | 617 | /* output is in 7.9(q9) format for the 64 point */ |
emilmont | 1:fdd22bb7aa52 | 618 | /* output is in 5.11(q11) format for the 16 point */ |
emilmont | 1:fdd22bb7aa52 | 619 | |
emilmont | 1:fdd22bb7aa52 | 620 | |
emilmont | 1:fdd22bb7aa52 | 621 | #else |
emilmont | 1:fdd22bb7aa52 | 622 | |
emilmont | 1:fdd22bb7aa52 | 623 | /* Run the below code for Cortex-M0 */ |
emilmont | 1:fdd22bb7aa52 | 624 | |
emilmont | 1:fdd22bb7aa52 | 625 | q15_t R0, R1, S0, S1, T0, T1, U0, U1; |
emilmont | 1:fdd22bb7aa52 | 626 | q15_t Co1, Si1, Co2, Si2, Co3, Si3, out1, out2; |
emilmont | 1:fdd22bb7aa52 | 627 | uint32_t n1, n2, ic, i0, i1, i2, i3, j, k; |
emilmont | 1:fdd22bb7aa52 | 628 | |
emilmont | 1:fdd22bb7aa52 | 629 | /* Total process is divided into three stages */ |
emilmont | 1:fdd22bb7aa52 | 630 | |
emilmont | 1:fdd22bb7aa52 | 631 | /* process first stage, middle stages, & last stage */ |
emilmont | 1:fdd22bb7aa52 | 632 | |
emilmont | 1:fdd22bb7aa52 | 633 | /* Initializations for the first stage */ |
emilmont | 1:fdd22bb7aa52 | 634 | n2 = fftLen; |
emilmont | 1:fdd22bb7aa52 | 635 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 636 | |
emilmont | 1:fdd22bb7aa52 | 637 | /* n2 = fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 638 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 639 | |
emilmont | 1:fdd22bb7aa52 | 640 | /* Index for twiddle coefficient */ |
emilmont | 1:fdd22bb7aa52 | 641 | ic = 0u; |
emilmont | 1:fdd22bb7aa52 | 642 | |
emilmont | 1:fdd22bb7aa52 | 643 | /* Index for input read and output write */ |
emilmont | 1:fdd22bb7aa52 | 644 | i0 = 0u; |
emilmont | 1:fdd22bb7aa52 | 645 | j = n2; |
emilmont | 1:fdd22bb7aa52 | 646 | |
emilmont | 1:fdd22bb7aa52 | 647 | /* Input is in 1.15(q15) format */ |
emilmont | 1:fdd22bb7aa52 | 648 | |
emilmont | 1:fdd22bb7aa52 | 649 | /* start of first stage process */ |
emilmont | 1:fdd22bb7aa52 | 650 | do |
emilmont | 1:fdd22bb7aa52 | 651 | { |
emilmont | 1:fdd22bb7aa52 | 652 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 653 | |
emilmont | 1:fdd22bb7aa52 | 654 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 655 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 656 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 657 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 658 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 659 | |
emilmont | 1:fdd22bb7aa52 | 660 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 661 | |
emilmont | 1:fdd22bb7aa52 | 662 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 663 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 664 | T0 = pSrc16[i0 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 665 | T1 = pSrc16[(i0 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 666 | |
emilmont | 1:fdd22bb7aa52 | 667 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 668 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 669 | S0 = pSrc16[i2 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 670 | S1 = pSrc16[(i2 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 671 | |
emilmont | 1:fdd22bb7aa52 | 672 | /* R0 = (ya + yc) */ |
emilmont | 1:fdd22bb7aa52 | 673 | R0 = __SSAT(T0 + S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 674 | /* R1 = (xa + xc) */ |
emilmont | 1:fdd22bb7aa52 | 675 | R1 = __SSAT(T1 + S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 676 | |
emilmont | 1:fdd22bb7aa52 | 677 | /* S0 = (ya - yc) */ |
emilmont | 1:fdd22bb7aa52 | 678 | S0 = __SSAT(T0 - S0, 16); |
emilmont | 1:fdd22bb7aa52 | 679 | /* S1 = (xa - xc) */ |
emilmont | 1:fdd22bb7aa52 | 680 | S1 = __SSAT(T1 - S1, 16); |
emilmont | 1:fdd22bb7aa52 | 681 | |
emilmont | 1:fdd22bb7aa52 | 682 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 683 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 684 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 685 | T0 = pSrc16[i1 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 686 | T1 = pSrc16[(i1 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 687 | |
emilmont | 1:fdd22bb7aa52 | 688 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 689 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 690 | U0 = pSrc16[i3 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 691 | U1 = pSrc16[(i3 * 2u) + 1] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 692 | |
emilmont | 1:fdd22bb7aa52 | 693 | /* T0 = (yb + yd) */ |
emilmont | 1:fdd22bb7aa52 | 694 | T0 = __SSAT(T0 + U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 695 | /* T1 = (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 696 | T1 = __SSAT(T1 + U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 697 | |
emilmont | 1:fdd22bb7aa52 | 698 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 699 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 700 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 701 | pSrc16[i0 * 2u] = (R0 >> 1u) + (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 702 | pSrc16[(i0 * 2u) + 1u] = (R1 >> 1u) + (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 703 | |
emilmont | 1:fdd22bb7aa52 | 704 | /* R0 = (ya + yc) - (yb + yd) */ |
emilmont | 1:fdd22bb7aa52 | 705 | /* R1 = (xa + xc) - (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 706 | R0 = __SSAT(R0 - T0, 16u); |
emilmont | 1:fdd22bb7aa52 | 707 | R1 = __SSAT(R1 - T1, 16u); |
emilmont | 1:fdd22bb7aa52 | 708 | |
emilmont | 1:fdd22bb7aa52 | 709 | /* co2 & si2 are read from Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 710 | Co2 = pCoef16[2u * ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 711 | Si2 = pCoef16[(2u * ic * 2u) + 1]; |
emilmont | 1:fdd22bb7aa52 | 712 | |
emilmont | 1:fdd22bb7aa52 | 713 | /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 714 | out1 = (short) ((Co2 * R0 + Si2 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 715 | /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 716 | out2 = (short) ((-Si2 * R0 + Co2 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 717 | |
emilmont | 1:fdd22bb7aa52 | 718 | /* Reading i0+fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 719 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 720 | /* T0 = yb, T1 = xb */ |
emilmont | 1:fdd22bb7aa52 | 721 | T0 = pSrc16[i1 * 2u] >> 2; |
emilmont | 1:fdd22bb7aa52 | 722 | T1 = pSrc16[(i1 * 2u) + 1] >> 2; |
emilmont | 1:fdd22bb7aa52 | 723 | |
emilmont | 1:fdd22bb7aa52 | 724 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 725 | /* writing output(xc', yc') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 726 | pSrc16[i1 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 727 | pSrc16[(i1 * 2u) + 1] = out2; |
emilmont | 1:fdd22bb7aa52 | 728 | |
emilmont | 1:fdd22bb7aa52 | 729 | /* Butterfly calculations */ |
emilmont | 1:fdd22bb7aa52 | 730 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 731 | /* U0 = yd, U1 = xd */ |
emilmont | 1:fdd22bb7aa52 | 732 | U0 = pSrc16[i3 * 2u] >> 2; |
emilmont | 1:fdd22bb7aa52 | 733 | U1 = pSrc16[(i3 * 2u) + 1] >> 2; |
emilmont | 1:fdd22bb7aa52 | 734 | /* T0 = yb-yd */ |
emilmont | 1:fdd22bb7aa52 | 735 | T0 = __SSAT(T0 - U0, 16); |
emilmont | 1:fdd22bb7aa52 | 736 | /* T1 = xb-xd */ |
emilmont | 1:fdd22bb7aa52 | 737 | T1 = __SSAT(T1 - U1, 16); |
emilmont | 1:fdd22bb7aa52 | 738 | |
emilmont | 1:fdd22bb7aa52 | 739 | /* R1 = (ya-yc) + (xb- xd), R0 = (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 740 | R0 = (short) __SSAT((q31_t) (S0 - T1), 16); |
emilmont | 1:fdd22bb7aa52 | 741 | R1 = (short) __SSAT((q31_t) (S1 + T0), 16); |
emilmont | 1:fdd22bb7aa52 | 742 | |
emilmont | 1:fdd22bb7aa52 | 743 | /* S1 = (ya-yc) - (xb- xd), S0 = (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 744 | S0 = (short) __SSAT(((q31_t) S0 + T1), 16u); |
emilmont | 1:fdd22bb7aa52 | 745 | S1 = (short) __SSAT(((q31_t) S1 - T0), 16u); |
emilmont | 1:fdd22bb7aa52 | 746 | |
emilmont | 1:fdd22bb7aa52 | 747 | /* co1 & si1 are read from Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 748 | Co1 = pCoef16[ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 749 | Si1 = pCoef16[(ic * 2u) + 1]; |
emilmont | 1:fdd22bb7aa52 | 750 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 751 | /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 752 | out1 = (short) ((Si1 * S1 + Co1 * S0) >> 16); |
emilmont | 1:fdd22bb7aa52 | 753 | /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 754 | out2 = (short) ((-Si1 * S0 + Co1 * S1) >> 16); |
emilmont | 1:fdd22bb7aa52 | 755 | |
emilmont | 1:fdd22bb7aa52 | 756 | /* writing output(xb', yb') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 757 | pSrc16[i2 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 758 | pSrc16[(i2 * 2u) + 1] = out2; |
emilmont | 1:fdd22bb7aa52 | 759 | |
emilmont | 1:fdd22bb7aa52 | 760 | /* Co3 & si3 are read from Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 761 | Co3 = pCoef16[3u * (ic * 2u)]; |
emilmont | 1:fdd22bb7aa52 | 762 | Si3 = pCoef16[(3u * (ic * 2u)) + 1]; |
emilmont | 1:fdd22bb7aa52 | 763 | /* Butterfly process for the i0+3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 764 | /* xd' = (xa-yb-xc+yd)* Co3 + (ya+xb-yc-xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 765 | out1 = (short) ((Si3 * R1 + Co3 * R0) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 766 | /* yd' = (ya+xb-yc-xd)* Co3 - (xa-yb-xc+yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 767 | out2 = (short) ((-Si3 * R0 + Co3 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 768 | /* writing output(xd', yd') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 769 | pSrc16[i3 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 770 | pSrc16[(i3 * 2u) + 1] = out2; |
emilmont | 1:fdd22bb7aa52 | 771 | |
emilmont | 1:fdd22bb7aa52 | 772 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 773 | ic = ic + twidCoefModifier; |
emilmont | 1:fdd22bb7aa52 | 774 | |
emilmont | 1:fdd22bb7aa52 | 775 | /* Updating input index */ |
emilmont | 1:fdd22bb7aa52 | 776 | i0 = i0 + 1u; |
emilmont | 1:fdd22bb7aa52 | 777 | |
emilmont | 1:fdd22bb7aa52 | 778 | } while(--j); |
emilmont | 1:fdd22bb7aa52 | 779 | /* data is in 4.11(q11) format */ |
emilmont | 1:fdd22bb7aa52 | 780 | |
emilmont | 1:fdd22bb7aa52 | 781 | /* end of first stage process */ |
emilmont | 1:fdd22bb7aa52 | 782 | |
emilmont | 1:fdd22bb7aa52 | 783 | |
emilmont | 1:fdd22bb7aa52 | 784 | /* start of middle stage process */ |
emilmont | 1:fdd22bb7aa52 | 785 | |
emilmont | 1:fdd22bb7aa52 | 786 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 787 | twidCoefModifier <<= 2u; |
emilmont | 1:fdd22bb7aa52 | 788 | |
emilmont | 1:fdd22bb7aa52 | 789 | /* Calculation of Middle stage */ |
emilmont | 1:fdd22bb7aa52 | 790 | for (k = fftLen / 4u; k > 4u; k >>= 2u) |
emilmont | 1:fdd22bb7aa52 | 791 | { |
emilmont | 1:fdd22bb7aa52 | 792 | /* Initializations for the middle stage */ |
emilmont | 1:fdd22bb7aa52 | 793 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 794 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 795 | ic = 0u; |
emilmont | 1:fdd22bb7aa52 | 796 | |
emilmont | 1:fdd22bb7aa52 | 797 | for (j = 0u; j <= (n2 - 1u); j++) |
emilmont | 1:fdd22bb7aa52 | 798 | { |
emilmont | 1:fdd22bb7aa52 | 799 | /* index calculation for the coefficients */ |
emilmont | 1:fdd22bb7aa52 | 800 | Co1 = pCoef16[ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 801 | Si1 = pCoef16[(ic * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 802 | Co2 = pCoef16[2u * (ic * 2u)]; |
emilmont | 1:fdd22bb7aa52 | 803 | Si2 = pCoef16[(2u * (ic * 2u)) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 804 | Co3 = pCoef16[3u * (ic * 2u)]; |
emilmont | 1:fdd22bb7aa52 | 805 | Si3 = pCoef16[(3u * (ic * 2u)) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 806 | |
emilmont | 1:fdd22bb7aa52 | 807 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 808 | ic = ic + twidCoefModifier; |
emilmont | 1:fdd22bb7aa52 | 809 | |
emilmont | 1:fdd22bb7aa52 | 810 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 811 | for (i0 = j; i0 < fftLen; i0 += n1) |
emilmont | 1:fdd22bb7aa52 | 812 | { |
emilmont | 1:fdd22bb7aa52 | 813 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 814 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 815 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 816 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 817 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 818 | |
emilmont | 1:fdd22bb7aa52 | 819 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 820 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 821 | T0 = pSrc16[i0 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 822 | T1 = pSrc16[(i0 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 823 | |
emilmont | 1:fdd22bb7aa52 | 824 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 825 | S0 = pSrc16[i2 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 826 | S1 = pSrc16[(i2 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 827 | |
emilmont | 1:fdd22bb7aa52 | 828 | /* R0 = (ya + yc), R1 = (xa + xc) */ |
emilmont | 1:fdd22bb7aa52 | 829 | R0 = __SSAT(T0 + S0, 16); |
emilmont | 1:fdd22bb7aa52 | 830 | R1 = __SSAT(T1 + S1, 16); |
emilmont | 1:fdd22bb7aa52 | 831 | |
emilmont | 1:fdd22bb7aa52 | 832 | /* S0 = (ya - yc), S1 =(xa - xc) */ |
emilmont | 1:fdd22bb7aa52 | 833 | S0 = __SSAT(T0 - S0, 16); |
emilmont | 1:fdd22bb7aa52 | 834 | S1 = __SSAT(T1 - S1, 16); |
emilmont | 1:fdd22bb7aa52 | 835 | |
emilmont | 1:fdd22bb7aa52 | 836 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 837 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 838 | T0 = pSrc16[i1 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 839 | T1 = pSrc16[(i1 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 840 | |
emilmont | 1:fdd22bb7aa52 | 841 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 842 | U0 = pSrc16[i3 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 843 | U1 = pSrc16[(i3 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 844 | |
emilmont | 1:fdd22bb7aa52 | 845 | |
emilmont | 1:fdd22bb7aa52 | 846 | /* T0 = (yb + yd), T1 = (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 847 | T0 = __SSAT(T0 + U0, 16); |
emilmont | 1:fdd22bb7aa52 | 848 | T1 = __SSAT(T1 + U1, 16); |
emilmont | 1:fdd22bb7aa52 | 849 | |
emilmont | 1:fdd22bb7aa52 | 850 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 851 | |
emilmont | 1:fdd22bb7aa52 | 852 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 853 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 854 | out1 = ((R0 >> 1u) + (T0 >> 1u)) >> 1u; |
emilmont | 1:fdd22bb7aa52 | 855 | out2 = ((R1 >> 1u) + (T1 >> 1u)) >> 1u; |
emilmont | 1:fdd22bb7aa52 | 856 | |
emilmont | 1:fdd22bb7aa52 | 857 | pSrc16[i0 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 858 | pSrc16[(2u * i0) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 859 | |
emilmont | 1:fdd22bb7aa52 | 860 | /* R0 = (ya + yc) - (yb + yd), R1 = (xa + xc) - (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 861 | R0 = (R0 >> 1u) - (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 862 | R1 = (R1 >> 1u) - (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 863 | |
emilmont | 1:fdd22bb7aa52 | 864 | /* (ya-yb+yc-yd)* (si2) + (xa-xb+xc-xd)* co2 */ |
emilmont | 1:fdd22bb7aa52 | 865 | out1 = (short) ((Co2 * R0 + Si2 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 866 | |
emilmont | 1:fdd22bb7aa52 | 867 | /* (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 868 | out2 = (short) ((-Si2 * R0 + Co2 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 869 | |
emilmont | 1:fdd22bb7aa52 | 870 | /* Reading i0+3fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 871 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 872 | T0 = pSrc16[i1 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 873 | T1 = pSrc16[(i1 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 874 | |
emilmont | 1:fdd22bb7aa52 | 875 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 876 | /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 877 | /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 878 | pSrc16[i1 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 879 | pSrc16[(i1 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 880 | |
emilmont | 1:fdd22bb7aa52 | 881 | /* Butterfly calculations */ |
emilmont | 1:fdd22bb7aa52 | 882 | |
emilmont | 1:fdd22bb7aa52 | 883 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 884 | U0 = pSrc16[i3 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 885 | U1 = pSrc16[(i3 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 886 | |
emilmont | 1:fdd22bb7aa52 | 887 | /* T0 = yb-yd, T1 = xb-xd */ |
emilmont | 1:fdd22bb7aa52 | 888 | T0 = __SSAT(T0 - U0, 16); |
emilmont | 1:fdd22bb7aa52 | 889 | T1 = __SSAT(T1 - U1, 16); |
emilmont | 1:fdd22bb7aa52 | 890 | |
emilmont | 1:fdd22bb7aa52 | 891 | /* R0 = (ya-yc) + (xb- xd), R1 = (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 892 | R0 = (S0 >> 1u) - (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 893 | R1 = (S1 >> 1u) + (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 894 | |
emilmont | 1:fdd22bb7aa52 | 895 | /* S0 = (ya-yc) - (xb- xd), S1 = (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 896 | S0 = (S0 >> 1u) + (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 897 | S1 = (S1 >> 1u) - (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 898 | |
emilmont | 1:fdd22bb7aa52 | 899 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 900 | out1 = (short) ((Co1 * S0 + Si1 * S1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 901 | |
emilmont | 1:fdd22bb7aa52 | 902 | out2 = (short) ((-Si1 * S0 + Co1 * S1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 903 | |
emilmont | 1:fdd22bb7aa52 | 904 | /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 905 | /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 906 | pSrc16[i2 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 907 | pSrc16[(i2 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 908 | |
emilmont | 1:fdd22bb7aa52 | 909 | /* Butterfly process for the i0+3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 910 | out1 = (short) ((Si3 * R1 + Co3 * R0) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 911 | |
emilmont | 1:fdd22bb7aa52 | 912 | out2 = (short) ((-Si3 * R0 + Co3 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 913 | /* xd' = (xa-yb-xc+yd)* Co3 + (ya+xb-yc-xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 914 | /* yd' = (ya+xb-yc-xd)* Co3 - (xa-yb-xc+yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 915 | pSrc16[i3 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 916 | pSrc16[(i3 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 917 | } |
emilmont | 1:fdd22bb7aa52 | 918 | } |
emilmont | 1:fdd22bb7aa52 | 919 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 920 | twidCoefModifier <<= 2u; |
emilmont | 1:fdd22bb7aa52 | 921 | } |
emilmont | 1:fdd22bb7aa52 | 922 | /* end of middle stage process */ |
emilmont | 1:fdd22bb7aa52 | 923 | |
emilmont | 1:fdd22bb7aa52 | 924 | |
emilmont | 1:fdd22bb7aa52 | 925 | /* data is in 10.6(q6) format for the 1024 point */ |
emilmont | 1:fdd22bb7aa52 | 926 | /* data is in 8.8(q8) format for the 256 point */ |
emilmont | 1:fdd22bb7aa52 | 927 | /* data is in 6.10(q10) format for the 64 point */ |
emilmont | 1:fdd22bb7aa52 | 928 | /* data is in 4.12(q12) format for the 16 point */ |
emilmont | 1:fdd22bb7aa52 | 929 | |
emilmont | 1:fdd22bb7aa52 | 930 | /* Initializations for the last stage */ |
emilmont | 1:fdd22bb7aa52 | 931 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 932 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 933 | |
emilmont | 1:fdd22bb7aa52 | 934 | /* start of last stage process */ |
emilmont | 1:fdd22bb7aa52 | 935 | |
emilmont | 1:fdd22bb7aa52 | 936 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 937 | for (i0 = 0u; i0 <= (fftLen - n1); i0 += n1) |
emilmont | 1:fdd22bb7aa52 | 938 | { |
emilmont | 1:fdd22bb7aa52 | 939 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 940 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 941 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 942 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 943 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 944 | |
emilmont | 1:fdd22bb7aa52 | 945 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 946 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 947 | T0 = pSrc16[i0 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 948 | T1 = pSrc16[(i0 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 949 | |
emilmont | 1:fdd22bb7aa52 | 950 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 951 | S0 = pSrc16[i2 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 952 | S1 = pSrc16[(i2 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 953 | |
emilmont | 1:fdd22bb7aa52 | 954 | /* R0 = (ya + yc), R1 = (xa + xc) */ |
emilmont | 1:fdd22bb7aa52 | 955 | R0 = __SSAT(T0 + S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 956 | R1 = __SSAT(T1 + S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 957 | |
emilmont | 1:fdd22bb7aa52 | 958 | /* S0 = (ya - yc), S1 = (xa - xc) */ |
emilmont | 1:fdd22bb7aa52 | 959 | S0 = __SSAT(T0 - S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 960 | S1 = __SSAT(T1 - S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 961 | |
emilmont | 1:fdd22bb7aa52 | 962 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 963 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 964 | T0 = pSrc16[i1 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 965 | T1 = pSrc16[(i1 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 966 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 967 | U0 = pSrc16[i3 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 968 | U1 = pSrc16[(i3 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 969 | |
emilmont | 1:fdd22bb7aa52 | 970 | /* T0 = (yb + yd), T1 = (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 971 | T0 = __SSAT(T0 + U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 972 | T1 = __SSAT(T1 + U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 973 | |
emilmont | 1:fdd22bb7aa52 | 974 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 975 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 976 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 977 | pSrc16[i0 * 2u] = (R0 >> 1u) + (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 978 | pSrc16[(i0 * 2u) + 1u] = (R1 >> 1u) + (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 979 | |
emilmont | 1:fdd22bb7aa52 | 980 | /* R0 = (ya + yc) - (yb + yd), R1 = (xa + xc) - (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 981 | R0 = (R0 >> 1u) - (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 982 | R1 = (R1 >> 1u) - (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 983 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 984 | T0 = pSrc16[i1 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 985 | T1 = pSrc16[(i1 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 986 | |
emilmont | 1:fdd22bb7aa52 | 987 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 988 | /* xc' = (xa-xb+xc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 989 | /* yc' = (ya-yb+yc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 990 | pSrc16[i1 * 2u] = R0; |
emilmont | 1:fdd22bb7aa52 | 991 | pSrc16[(i1 * 2u) + 1u] = R1; |
emilmont | 1:fdd22bb7aa52 | 992 | |
emilmont | 1:fdd22bb7aa52 | 993 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 994 | U0 = pSrc16[i3 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 995 | U1 = pSrc16[(i3 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 996 | /* T0 = (yb - yd), T1 = (xb - xd) */ |
emilmont | 1:fdd22bb7aa52 | 997 | T0 = __SSAT(T0 - U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 998 | T1 = __SSAT(T1 - U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 999 | |
emilmont | 1:fdd22bb7aa52 | 1000 | /* writing the butterfly processed i0 + fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 1001 | /* xb' = (xa+yb-xc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1002 | /* yb' = (ya-xb-yc+xd) */ |
emilmont | 1:fdd22bb7aa52 | 1003 | pSrc16[i2 * 2u] = (S0 >> 1u) + (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1004 | pSrc16[(i2 * 2u) + 1u] = (S1 >> 1u) - (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1005 | |
emilmont | 1:fdd22bb7aa52 | 1006 | /* writing the butterfly processed i0 + 3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1007 | /* xd' = (xa-yb-xc+yd) */ |
emilmont | 1:fdd22bb7aa52 | 1008 | /* yd' = (ya+xb-yc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1009 | pSrc16[i3 * 2u] = (S0 >> 1u) - (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1010 | pSrc16[(i3 * 2u) + 1u] = (S1 >> 1u) + (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1011 | |
emilmont | 1:fdd22bb7aa52 | 1012 | } |
emilmont | 1:fdd22bb7aa52 | 1013 | |
emilmont | 1:fdd22bb7aa52 | 1014 | /* end of last stage process */ |
emilmont | 1:fdd22bb7aa52 | 1015 | |
emilmont | 1:fdd22bb7aa52 | 1016 | /* output is in 11.5(q5) format for the 1024 point */ |
emilmont | 1:fdd22bb7aa52 | 1017 | /* output is in 9.7(q7) format for the 256 point */ |
emilmont | 1:fdd22bb7aa52 | 1018 | /* output is in 7.9(q9) format for the 64 point */ |
emilmont | 1:fdd22bb7aa52 | 1019 | /* output is in 5.11(q11) format for the 16 point */ |
emilmont | 1:fdd22bb7aa52 | 1020 | |
mbed_official | 3:7a284390b0ce | 1021 | #endif /* #ifndef ARM_MATH_CM0_FAMILY */ |
emilmont | 1:fdd22bb7aa52 | 1022 | |
emilmont | 1:fdd22bb7aa52 | 1023 | } |
emilmont | 1:fdd22bb7aa52 | 1024 | |
emilmont | 1:fdd22bb7aa52 | 1025 | |
emilmont | 1:fdd22bb7aa52 | 1026 | /** |
emilmont | 1:fdd22bb7aa52 | 1027 | * @brief Core function for the Q15 CIFFT butterfly process. |
emilmont | 1:fdd22bb7aa52 | 1028 | * @param[in, out] *pSrc16 points to the in-place buffer of Q15 data type. |
emilmont | 1:fdd22bb7aa52 | 1029 | * @param[in] fftLen length of the FFT. |
emilmont | 1:fdd22bb7aa52 | 1030 | * @param[in] *pCoef16 points to twiddle coefficient buffer. |
emilmont | 1:fdd22bb7aa52 | 1031 | * @param[in] twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table. |
emilmont | 1:fdd22bb7aa52 | 1032 | * @return none. |
emilmont | 1:fdd22bb7aa52 | 1033 | */ |
emilmont | 1:fdd22bb7aa52 | 1034 | |
emilmont | 1:fdd22bb7aa52 | 1035 | /* |
emilmont | 1:fdd22bb7aa52 | 1036 | * Radix-4 IFFT algorithm used is : |
emilmont | 1:fdd22bb7aa52 | 1037 | * |
emilmont | 1:fdd22bb7aa52 | 1038 | * CIFFT uses same twiddle coefficients as CFFT function |
emilmont | 1:fdd22bb7aa52 | 1039 | * x[k] = x[n] + (j)k * x[n + fftLen/4] + (-1)k * x[n+fftLen/2] + (-j)k * x[n+3*fftLen/4] |
emilmont | 1:fdd22bb7aa52 | 1040 | * |
emilmont | 1:fdd22bb7aa52 | 1041 | * |
emilmont | 1:fdd22bb7aa52 | 1042 | * IFFT is implemented with following changes in equations from FFT |
emilmont | 1:fdd22bb7aa52 | 1043 | * |
emilmont | 1:fdd22bb7aa52 | 1044 | * Input real and imaginary data: |
emilmont | 1:fdd22bb7aa52 | 1045 | * x(n) = xa + j * ya |
emilmont | 1:fdd22bb7aa52 | 1046 | * x(n+N/4 ) = xb + j * yb |
emilmont | 1:fdd22bb7aa52 | 1047 | * x(n+N/2 ) = xc + j * yc |
emilmont | 1:fdd22bb7aa52 | 1048 | * x(n+3N 4) = xd + j * yd |
emilmont | 1:fdd22bb7aa52 | 1049 | * |
emilmont | 1:fdd22bb7aa52 | 1050 | * |
emilmont | 1:fdd22bb7aa52 | 1051 | * Output real and imaginary data: |
emilmont | 1:fdd22bb7aa52 | 1052 | * x(4r) = xa'+ j * ya' |
emilmont | 1:fdd22bb7aa52 | 1053 | * x(4r+1) = xb'+ j * yb' |
emilmont | 1:fdd22bb7aa52 | 1054 | * x(4r+2) = xc'+ j * yc' |
emilmont | 1:fdd22bb7aa52 | 1055 | * x(4r+3) = xd'+ j * yd' |
emilmont | 1:fdd22bb7aa52 | 1056 | * |
emilmont | 1:fdd22bb7aa52 | 1057 | * |
emilmont | 1:fdd22bb7aa52 | 1058 | * Twiddle factors for radix-4 IFFT: |
emilmont | 1:fdd22bb7aa52 | 1059 | * Wn = co1 + j * (si1) |
emilmont | 1:fdd22bb7aa52 | 1060 | * W2n = co2 + j * (si2) |
emilmont | 1:fdd22bb7aa52 | 1061 | * W3n = co3 + j * (si3) |
emilmont | 1:fdd22bb7aa52 | 1062 | |
emilmont | 1:fdd22bb7aa52 | 1063 | * The real and imaginary output values for the radix-4 butterfly are |
emilmont | 1:fdd22bb7aa52 | 1064 | * xa' = xa + xb + xc + xd |
emilmont | 1:fdd22bb7aa52 | 1065 | * ya' = ya + yb + yc + yd |
emilmont | 1:fdd22bb7aa52 | 1066 | * xb' = (xa-yb-xc+yd)* co1 - (ya+xb-yc-xd)* (si1) |
emilmont | 1:fdd22bb7aa52 | 1067 | * yb' = (ya+xb-yc-xd)* co1 + (xa-yb-xc+yd)* (si1) |
emilmont | 1:fdd22bb7aa52 | 1068 | * xc' = (xa-xb+xc-xd)* co2 - (ya-yb+yc-yd)* (si2) |
emilmont | 1:fdd22bb7aa52 | 1069 | * yc' = (ya-yb+yc-yd)* co2 + (xa-xb+xc-xd)* (si2) |
emilmont | 1:fdd22bb7aa52 | 1070 | * xd' = (xa+yb-xc-yd)* co3 - (ya-xb-yc+xd)* (si3) |
emilmont | 1:fdd22bb7aa52 | 1071 | * yd' = (ya-xb-yc+xd)* co3 + (xa+yb-xc-yd)* (si3) |
emilmont | 1:fdd22bb7aa52 | 1072 | * |
emilmont | 1:fdd22bb7aa52 | 1073 | */ |
emilmont | 1:fdd22bb7aa52 | 1074 | |
emilmont | 1:fdd22bb7aa52 | 1075 | void arm_radix4_butterfly_inverse_q15( |
emilmont | 1:fdd22bb7aa52 | 1076 | q15_t * pSrc16, |
emilmont | 1:fdd22bb7aa52 | 1077 | uint32_t fftLen, |
emilmont | 1:fdd22bb7aa52 | 1078 | q15_t * pCoef16, |
emilmont | 1:fdd22bb7aa52 | 1079 | uint32_t twidCoefModifier) |
emilmont | 1:fdd22bb7aa52 | 1080 | { |
emilmont | 1:fdd22bb7aa52 | 1081 | |
mbed_official | 3:7a284390b0ce | 1082 | #ifndef ARM_MATH_CM0_FAMILY |
emilmont | 1:fdd22bb7aa52 | 1083 | |
emilmont | 1:fdd22bb7aa52 | 1084 | /* Run the below code for Cortex-M4 and Cortex-M3 */ |
emilmont | 1:fdd22bb7aa52 | 1085 | |
emilmont | 1:fdd22bb7aa52 | 1086 | q31_t R, S, T, U; |
emilmont | 1:fdd22bb7aa52 | 1087 | q31_t C1, C2, C3, out1, out2; |
emilmont | 1:fdd22bb7aa52 | 1088 | uint32_t n1, n2, ic, i0, i1, i2, i3, j, k; |
emilmont | 1:fdd22bb7aa52 | 1089 | q15_t in; |
emilmont | 1:fdd22bb7aa52 | 1090 | |
emilmont | 1:fdd22bb7aa52 | 1091 | q15_t *ptr1; |
emilmont | 1:fdd22bb7aa52 | 1092 | |
emilmont | 1:fdd22bb7aa52 | 1093 | |
emilmont | 1:fdd22bb7aa52 | 1094 | |
emilmont | 1:fdd22bb7aa52 | 1095 | q31_t xaya, xbyb, xcyc, xdyd; |
emilmont | 1:fdd22bb7aa52 | 1096 | |
emilmont | 1:fdd22bb7aa52 | 1097 | /* Total process is divided into three stages */ |
emilmont | 1:fdd22bb7aa52 | 1098 | |
emilmont | 1:fdd22bb7aa52 | 1099 | /* process first stage, middle stages, & last stage */ |
emilmont | 1:fdd22bb7aa52 | 1100 | |
emilmont | 1:fdd22bb7aa52 | 1101 | /* Initializations for the first stage */ |
emilmont | 1:fdd22bb7aa52 | 1102 | n2 = fftLen; |
emilmont | 1:fdd22bb7aa52 | 1103 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 1104 | |
emilmont | 1:fdd22bb7aa52 | 1105 | /* n2 = fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 1106 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 1107 | |
emilmont | 1:fdd22bb7aa52 | 1108 | /* Index for twiddle coefficient */ |
emilmont | 1:fdd22bb7aa52 | 1109 | ic = 0u; |
emilmont | 1:fdd22bb7aa52 | 1110 | |
emilmont | 1:fdd22bb7aa52 | 1111 | /* Index for input read and output write */ |
emilmont | 1:fdd22bb7aa52 | 1112 | i0 = 0u; |
emilmont | 1:fdd22bb7aa52 | 1113 | j = n2; |
emilmont | 1:fdd22bb7aa52 | 1114 | |
emilmont | 1:fdd22bb7aa52 | 1115 | /* Input is in 1.15(q15) format */ |
emilmont | 1:fdd22bb7aa52 | 1116 | |
emilmont | 1:fdd22bb7aa52 | 1117 | /* start of first stage process */ |
emilmont | 1:fdd22bb7aa52 | 1118 | do |
emilmont | 1:fdd22bb7aa52 | 1119 | { |
emilmont | 1:fdd22bb7aa52 | 1120 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 1121 | |
emilmont | 1:fdd22bb7aa52 | 1122 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 1123 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 1124 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 1125 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 1126 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 1127 | |
emilmont | 1:fdd22bb7aa52 | 1128 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1129 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1130 | T = _SIMD32_OFFSET(pSrc16 + (2u * i0)); |
emilmont | 1:fdd22bb7aa52 | 1131 | in = ((int16_t) (T & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 1132 | T = ((T >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 1133 | |
emilmont | 1:fdd22bb7aa52 | 1134 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1135 | S = _SIMD32_OFFSET(pSrc16 + (2u * i2)); |
emilmont | 1:fdd22bb7aa52 | 1136 | in = ((int16_t) (S & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 1137 | S = ((S >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 1138 | |
emilmont | 1:fdd22bb7aa52 | 1139 | /* R = packed((ya + yc), (xa + xc) ) */ |
emilmont | 1:fdd22bb7aa52 | 1140 | R = __QADD16(T, S); |
emilmont | 1:fdd22bb7aa52 | 1141 | |
emilmont | 1:fdd22bb7aa52 | 1142 | /* S = packed((ya - yc), (xa - xc) ) */ |
emilmont | 1:fdd22bb7aa52 | 1143 | S = __QSUB16(T, S); |
emilmont | 1:fdd22bb7aa52 | 1144 | |
emilmont | 1:fdd22bb7aa52 | 1145 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1146 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1147 | T = _SIMD32_OFFSET(pSrc16 + (2u * i1)); |
emilmont | 1:fdd22bb7aa52 | 1148 | in = ((int16_t) (T & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 1149 | T = ((T >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 1150 | |
emilmont | 1:fdd22bb7aa52 | 1151 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1152 | U = _SIMD32_OFFSET(pSrc16 + (2u * i3)); |
emilmont | 1:fdd22bb7aa52 | 1153 | in = ((int16_t) (U & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 1154 | U = ((U >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 1155 | |
emilmont | 1:fdd22bb7aa52 | 1156 | /* T = packed((yb + yd), (xb + xd) ) */ |
emilmont | 1:fdd22bb7aa52 | 1157 | T = __QADD16(T, U); |
emilmont | 1:fdd22bb7aa52 | 1158 | |
emilmont | 1:fdd22bb7aa52 | 1159 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 1160 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 1161 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 1162 | _SIMD32_OFFSET(pSrc16 + (2u * i0)) = __SHADD16(R, T); |
emilmont | 1:fdd22bb7aa52 | 1163 | |
emilmont | 1:fdd22bb7aa52 | 1164 | /* R = packed((ya + yc) - (yb + yd), (xa + xc)- (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 1165 | R = __QSUB16(R, T); |
emilmont | 1:fdd22bb7aa52 | 1166 | |
emilmont | 1:fdd22bb7aa52 | 1167 | /* co2 & si2 are read from SIMD Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 1168 | C2 = _SIMD32_OFFSET(pCoef16 + (4u * ic)); |
emilmont | 1:fdd22bb7aa52 | 1169 | |
emilmont | 1:fdd22bb7aa52 | 1170 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 1171 | |
emilmont | 1:fdd22bb7aa52 | 1172 | /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1173 | out1 = __SMUSD(C2, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1174 | /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1175 | out2 = __SMUADX(C2, R); |
emilmont | 1:fdd22bb7aa52 | 1176 | |
emilmont | 1:fdd22bb7aa52 | 1177 | #else |
emilmont | 1:fdd22bb7aa52 | 1178 | |
emilmont | 1:fdd22bb7aa52 | 1179 | /* xc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1180 | out1 = __SMUADX(C2, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1181 | /* yc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1182 | out2 = __SMUSD(__QSUB16(0, C2), R); |
emilmont | 1:fdd22bb7aa52 | 1183 | |
emilmont | 1:fdd22bb7aa52 | 1184 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 1185 | |
emilmont | 1:fdd22bb7aa52 | 1186 | /* Reading i0+fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 1187 | /* T = packed(yb, xb) */ |
emilmont | 1:fdd22bb7aa52 | 1188 | T = _SIMD32_OFFSET(pSrc16 + (2u * i1)); |
emilmont | 1:fdd22bb7aa52 | 1189 | in = ((int16_t) (T & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 1190 | T = ((T >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 1191 | |
emilmont | 1:fdd22bb7aa52 | 1192 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1193 | /* writing output(xc', yc') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 1194 | _SIMD32_OFFSET(pSrc16 + (2u * i1)) = |
emilmont | 1:fdd22bb7aa52 | 1195 | (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 1196 | |
emilmont | 1:fdd22bb7aa52 | 1197 | /* Butterfly calculations */ |
emilmont | 1:fdd22bb7aa52 | 1198 | /* U = packed(yd, xd) */ |
emilmont | 1:fdd22bb7aa52 | 1199 | U = _SIMD32_OFFSET(pSrc16 + (2u * i3)); |
emilmont | 1:fdd22bb7aa52 | 1200 | in = ((int16_t) (U & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 1201 | U = ((U >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 1202 | |
emilmont | 1:fdd22bb7aa52 | 1203 | /* T = packed(yb-yd, xb-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1204 | T = __QSUB16(T, U); |
emilmont | 1:fdd22bb7aa52 | 1205 | |
emilmont | 1:fdd22bb7aa52 | 1206 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 1207 | |
emilmont | 1:fdd22bb7aa52 | 1208 | /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 1209 | R = __QSAX(S, T); |
emilmont | 1:fdd22bb7aa52 | 1210 | /* S = packed((ya-yc) + (xb- xd), (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 1211 | S = __QASX(S, T); |
emilmont | 1:fdd22bb7aa52 | 1212 | |
emilmont | 1:fdd22bb7aa52 | 1213 | #else |
emilmont | 1:fdd22bb7aa52 | 1214 | |
emilmont | 1:fdd22bb7aa52 | 1215 | /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 1216 | R = __QASX(S, T); |
emilmont | 1:fdd22bb7aa52 | 1217 | /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 1218 | S = __QSAX(S, T); |
emilmont | 1:fdd22bb7aa52 | 1219 | |
emilmont | 1:fdd22bb7aa52 | 1220 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 1221 | |
emilmont | 1:fdd22bb7aa52 | 1222 | /* co1 & si1 are read from SIMD Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 1223 | C1 = _SIMD32_OFFSET(pCoef16 + (2u * ic)); |
emilmont | 1:fdd22bb7aa52 | 1224 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 1225 | |
emilmont | 1:fdd22bb7aa52 | 1226 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 1227 | |
emilmont | 1:fdd22bb7aa52 | 1228 | /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1229 | out1 = __SMUSD(C1, S) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1230 | /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1231 | out2 = __SMUADX(C1, S); |
emilmont | 1:fdd22bb7aa52 | 1232 | |
emilmont | 1:fdd22bb7aa52 | 1233 | #else |
emilmont | 1:fdd22bb7aa52 | 1234 | |
emilmont | 1:fdd22bb7aa52 | 1235 | /* xb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1236 | out1 = __SMUADX(C1, S) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1237 | /* yb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1238 | out2 = __SMUSD(__QSUB16(0, C1), S); |
emilmont | 1:fdd22bb7aa52 | 1239 | |
emilmont | 1:fdd22bb7aa52 | 1240 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 1241 | |
emilmont | 1:fdd22bb7aa52 | 1242 | /* writing output(xb', yb') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 1243 | _SIMD32_OFFSET(pSrc16 + (2u * i2)) = |
emilmont | 1:fdd22bb7aa52 | 1244 | ((out2) & 0xFFFF0000) | ((out1) & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 1245 | |
emilmont | 1:fdd22bb7aa52 | 1246 | |
emilmont | 1:fdd22bb7aa52 | 1247 | /* co3 & si3 are read from SIMD Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 1248 | C3 = _SIMD32_OFFSET(pCoef16 + (6u * ic)); |
emilmont | 1:fdd22bb7aa52 | 1249 | /* Butterfly process for the i0+3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1250 | |
emilmont | 1:fdd22bb7aa52 | 1251 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 1252 | |
emilmont | 1:fdd22bb7aa52 | 1253 | /* xd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1254 | out1 = __SMUSD(C3, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1255 | /* yd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1256 | out2 = __SMUADX(C3, R); |
emilmont | 1:fdd22bb7aa52 | 1257 | |
emilmont | 1:fdd22bb7aa52 | 1258 | #else |
emilmont | 1:fdd22bb7aa52 | 1259 | |
emilmont | 1:fdd22bb7aa52 | 1260 | /* xd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1261 | out1 = __SMUADX(C3, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1262 | /* yd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1263 | out2 = __SMUSD(__QSUB16(0, C3), R); |
emilmont | 1:fdd22bb7aa52 | 1264 | |
emilmont | 1:fdd22bb7aa52 | 1265 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 1266 | |
emilmont | 1:fdd22bb7aa52 | 1267 | /* writing output(xd', yd') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 1268 | _SIMD32_OFFSET(pSrc16 + (2u * i3)) = |
emilmont | 1:fdd22bb7aa52 | 1269 | ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 1270 | |
emilmont | 1:fdd22bb7aa52 | 1271 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 1272 | ic = ic + twidCoefModifier; |
emilmont | 1:fdd22bb7aa52 | 1273 | |
emilmont | 1:fdd22bb7aa52 | 1274 | /* Updating input index */ |
emilmont | 1:fdd22bb7aa52 | 1275 | i0 = i0 + 1u; |
emilmont | 1:fdd22bb7aa52 | 1276 | |
emilmont | 1:fdd22bb7aa52 | 1277 | } while(--j); |
emilmont | 1:fdd22bb7aa52 | 1278 | /* data is in 4.11(q11) format */ |
emilmont | 1:fdd22bb7aa52 | 1279 | |
emilmont | 1:fdd22bb7aa52 | 1280 | /* end of first stage process */ |
emilmont | 1:fdd22bb7aa52 | 1281 | |
emilmont | 1:fdd22bb7aa52 | 1282 | |
emilmont | 1:fdd22bb7aa52 | 1283 | /* start of middle stage process */ |
emilmont | 1:fdd22bb7aa52 | 1284 | |
emilmont | 1:fdd22bb7aa52 | 1285 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 1286 | twidCoefModifier <<= 2u; |
emilmont | 1:fdd22bb7aa52 | 1287 | |
emilmont | 1:fdd22bb7aa52 | 1288 | /* Calculation of Middle stage */ |
emilmont | 1:fdd22bb7aa52 | 1289 | for (k = fftLen / 4u; k > 4u; k >>= 2u) |
emilmont | 1:fdd22bb7aa52 | 1290 | { |
emilmont | 1:fdd22bb7aa52 | 1291 | /* Initializations for the middle stage */ |
emilmont | 1:fdd22bb7aa52 | 1292 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 1293 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 1294 | ic = 0u; |
emilmont | 1:fdd22bb7aa52 | 1295 | |
emilmont | 1:fdd22bb7aa52 | 1296 | for (j = 0u; j <= (n2 - 1u); j++) |
emilmont | 1:fdd22bb7aa52 | 1297 | { |
emilmont | 1:fdd22bb7aa52 | 1298 | /* index calculation for the coefficients */ |
emilmont | 1:fdd22bb7aa52 | 1299 | C1 = _SIMD32_OFFSET(pCoef16 + (2u * ic)); |
emilmont | 1:fdd22bb7aa52 | 1300 | C2 = _SIMD32_OFFSET(pCoef16 + (4u * ic)); |
emilmont | 1:fdd22bb7aa52 | 1301 | C3 = _SIMD32_OFFSET(pCoef16 + (6u * ic)); |
emilmont | 1:fdd22bb7aa52 | 1302 | |
emilmont | 1:fdd22bb7aa52 | 1303 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 1304 | ic = ic + twidCoefModifier; |
emilmont | 1:fdd22bb7aa52 | 1305 | |
emilmont | 1:fdd22bb7aa52 | 1306 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 1307 | for (i0 = j; i0 < fftLen; i0 += n1) |
emilmont | 1:fdd22bb7aa52 | 1308 | { |
emilmont | 1:fdd22bb7aa52 | 1309 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 1310 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 1311 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 1312 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 1313 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 1314 | |
emilmont | 1:fdd22bb7aa52 | 1315 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1316 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1317 | T = _SIMD32_OFFSET(pSrc16 + (2u * i0)); |
emilmont | 1:fdd22bb7aa52 | 1318 | |
emilmont | 1:fdd22bb7aa52 | 1319 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1320 | S = _SIMD32_OFFSET(pSrc16 + (2u * i2)); |
emilmont | 1:fdd22bb7aa52 | 1321 | |
emilmont | 1:fdd22bb7aa52 | 1322 | /* R = packed( (ya + yc), (xa + xc)) */ |
emilmont | 1:fdd22bb7aa52 | 1323 | R = __QADD16(T, S); |
emilmont | 1:fdd22bb7aa52 | 1324 | |
emilmont | 1:fdd22bb7aa52 | 1325 | /* S = packed((ya - yc), (xa - xc)) */ |
emilmont | 1:fdd22bb7aa52 | 1326 | S = __QSUB16(T, S); |
emilmont | 1:fdd22bb7aa52 | 1327 | |
emilmont | 1:fdd22bb7aa52 | 1328 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1329 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1330 | T = _SIMD32_OFFSET(pSrc16 + (2u * i1)); |
emilmont | 1:fdd22bb7aa52 | 1331 | |
emilmont | 1:fdd22bb7aa52 | 1332 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1333 | U = _SIMD32_OFFSET(pSrc16 + (2u * i3)); |
emilmont | 1:fdd22bb7aa52 | 1334 | |
emilmont | 1:fdd22bb7aa52 | 1335 | /* T = packed( (yb + yd), (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 1336 | T = __QADD16(T, U); |
emilmont | 1:fdd22bb7aa52 | 1337 | |
emilmont | 1:fdd22bb7aa52 | 1338 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 1339 | |
emilmont | 1:fdd22bb7aa52 | 1340 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 1341 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 1342 | out1 = __SHADD16(R, T); |
emilmont | 1:fdd22bb7aa52 | 1343 | in = ((int16_t) (out1 & 0xFFFF)) >> 1; |
emilmont | 1:fdd22bb7aa52 | 1344 | out1 = ((out1 >> 1) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 1345 | _SIMD32_OFFSET(pSrc16 + (2u * i0)) = out1; |
emilmont | 1:fdd22bb7aa52 | 1346 | |
emilmont | 1:fdd22bb7aa52 | 1347 | /* R = packed( (ya + yc) - (yb + yd), (xa + xc) - (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 1348 | R = __SHSUB16(R, T); |
emilmont | 1:fdd22bb7aa52 | 1349 | |
emilmont | 1:fdd22bb7aa52 | 1350 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 1351 | |
emilmont | 1:fdd22bb7aa52 | 1352 | /* (ya-yb+yc-yd)* (si2) + (xa-xb+xc-xd)* co2 */ |
emilmont | 1:fdd22bb7aa52 | 1353 | out1 = __SMUSD(C2, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1354 | |
emilmont | 1:fdd22bb7aa52 | 1355 | /* (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1356 | out2 = __SMUADX(C2, R); |
emilmont | 1:fdd22bb7aa52 | 1357 | |
emilmont | 1:fdd22bb7aa52 | 1358 | #else |
emilmont | 1:fdd22bb7aa52 | 1359 | |
emilmont | 1:fdd22bb7aa52 | 1360 | /* (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1361 | out1 = __SMUADX(R, C2) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1362 | |
emilmont | 1:fdd22bb7aa52 | 1363 | /* (ya-yb+yc-yd)* (si2) + (xa-xb+xc-xd)* co2 */ |
emilmont | 1:fdd22bb7aa52 | 1364 | out2 = __SMUSD(__QSUB16(0, C2), R); |
emilmont | 1:fdd22bb7aa52 | 1365 | |
emilmont | 1:fdd22bb7aa52 | 1366 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 1367 | |
emilmont | 1:fdd22bb7aa52 | 1368 | /* Reading i0+3fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 1369 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1370 | T = _SIMD32_OFFSET(pSrc16 + (2u * i1)); |
emilmont | 1:fdd22bb7aa52 | 1371 | |
emilmont | 1:fdd22bb7aa52 | 1372 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1373 | /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1374 | /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1375 | _SIMD32_OFFSET(pSrc16 + (2u * i1)) = |
emilmont | 1:fdd22bb7aa52 | 1376 | ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 1377 | |
emilmont | 1:fdd22bb7aa52 | 1378 | /* Butterfly calculations */ |
emilmont | 1:fdd22bb7aa52 | 1379 | |
emilmont | 1:fdd22bb7aa52 | 1380 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1381 | U = _SIMD32_OFFSET(pSrc16 + (2u * i3)); |
emilmont | 1:fdd22bb7aa52 | 1382 | |
emilmont | 1:fdd22bb7aa52 | 1383 | /* T = packed(yb-yd, xb-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1384 | T = __QSUB16(T, U); |
emilmont | 1:fdd22bb7aa52 | 1385 | |
emilmont | 1:fdd22bb7aa52 | 1386 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 1387 | |
emilmont | 1:fdd22bb7aa52 | 1388 | /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 1389 | R = __SHSAX(S, T); |
emilmont | 1:fdd22bb7aa52 | 1390 | |
emilmont | 1:fdd22bb7aa52 | 1391 | /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 1392 | S = __SHASX(S, T); |
emilmont | 1:fdd22bb7aa52 | 1393 | |
emilmont | 1:fdd22bb7aa52 | 1394 | |
emilmont | 1:fdd22bb7aa52 | 1395 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 1396 | out1 = __SMUSD(C1, S) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1397 | out2 = __SMUADX(C1, S); |
emilmont | 1:fdd22bb7aa52 | 1398 | |
emilmont | 1:fdd22bb7aa52 | 1399 | #else |
emilmont | 1:fdd22bb7aa52 | 1400 | |
emilmont | 1:fdd22bb7aa52 | 1401 | /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 1402 | R = __SHASX(S, T); |
emilmont | 1:fdd22bb7aa52 | 1403 | |
emilmont | 1:fdd22bb7aa52 | 1404 | /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 1405 | S = __SHSAX(S, T); |
emilmont | 1:fdd22bb7aa52 | 1406 | |
emilmont | 1:fdd22bb7aa52 | 1407 | |
emilmont | 1:fdd22bb7aa52 | 1408 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 1409 | out1 = __SMUADX(S, C1) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1410 | out2 = __SMUSD(__QSUB16(0, C1), S); |
emilmont | 1:fdd22bb7aa52 | 1411 | |
emilmont | 1:fdd22bb7aa52 | 1412 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 1413 | |
emilmont | 1:fdd22bb7aa52 | 1414 | /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1415 | /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1416 | _SIMD32_OFFSET(pSrc16 + (2u * i2)) = |
emilmont | 1:fdd22bb7aa52 | 1417 | ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 1418 | |
emilmont | 1:fdd22bb7aa52 | 1419 | /* Butterfly process for the i0+3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1420 | |
emilmont | 1:fdd22bb7aa52 | 1421 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 1422 | |
emilmont | 1:fdd22bb7aa52 | 1423 | out1 = __SMUSD(C3, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1424 | out2 = __SMUADX(C3, R); |
emilmont | 1:fdd22bb7aa52 | 1425 | |
emilmont | 1:fdd22bb7aa52 | 1426 | #else |
emilmont | 1:fdd22bb7aa52 | 1427 | |
emilmont | 1:fdd22bb7aa52 | 1428 | out1 = __SMUADX(C3, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1429 | out2 = __SMUSD(__QSUB16(0, C3), R); |
emilmont | 1:fdd22bb7aa52 | 1430 | |
emilmont | 1:fdd22bb7aa52 | 1431 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 1432 | |
emilmont | 1:fdd22bb7aa52 | 1433 | /* xd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1434 | /* yd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1435 | _SIMD32_OFFSET(pSrc16 + (2u * i3)) = |
emilmont | 1:fdd22bb7aa52 | 1436 | ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 1437 | } |
emilmont | 1:fdd22bb7aa52 | 1438 | } |
emilmont | 1:fdd22bb7aa52 | 1439 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 1440 | twidCoefModifier <<= 2u; |
emilmont | 1:fdd22bb7aa52 | 1441 | } |
emilmont | 1:fdd22bb7aa52 | 1442 | /* end of middle stage process */ |
emilmont | 1:fdd22bb7aa52 | 1443 | |
emilmont | 1:fdd22bb7aa52 | 1444 | /* data is in 10.6(q6) format for the 1024 point */ |
emilmont | 1:fdd22bb7aa52 | 1445 | /* data is in 8.8(q8) format for the 256 point */ |
emilmont | 1:fdd22bb7aa52 | 1446 | /* data is in 6.10(q10) format for the 64 point */ |
emilmont | 1:fdd22bb7aa52 | 1447 | /* data is in 4.12(q12) format for the 16 point */ |
emilmont | 1:fdd22bb7aa52 | 1448 | |
emilmont | 1:fdd22bb7aa52 | 1449 | /* Initializations for the last stage */ |
emilmont | 1:fdd22bb7aa52 | 1450 | j = fftLen >> 2; |
emilmont | 1:fdd22bb7aa52 | 1451 | |
emilmont | 1:fdd22bb7aa52 | 1452 | ptr1 = &pSrc16[0]; |
emilmont | 1:fdd22bb7aa52 | 1453 | |
emilmont | 1:fdd22bb7aa52 | 1454 | /* start of last stage process */ |
emilmont | 1:fdd22bb7aa52 | 1455 | |
emilmont | 1:fdd22bb7aa52 | 1456 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 1457 | do |
emilmont | 1:fdd22bb7aa52 | 1458 | { |
emilmont | 1:fdd22bb7aa52 | 1459 | /* Read xa (real), ya(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1460 | xaya = *__SIMD32(ptr1)++; |
emilmont | 1:fdd22bb7aa52 | 1461 | |
emilmont | 1:fdd22bb7aa52 | 1462 | /* Read xb (real), yb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1463 | xbyb = *__SIMD32(ptr1)++; |
emilmont | 1:fdd22bb7aa52 | 1464 | |
emilmont | 1:fdd22bb7aa52 | 1465 | /* Read xc (real), yc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1466 | xcyc = *__SIMD32(ptr1)++; |
emilmont | 1:fdd22bb7aa52 | 1467 | |
emilmont | 1:fdd22bb7aa52 | 1468 | /* Read xd (real), yd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1469 | xdyd = *__SIMD32(ptr1)++; |
emilmont | 1:fdd22bb7aa52 | 1470 | |
emilmont | 1:fdd22bb7aa52 | 1471 | /* R = packed((ya + yc), (xa + xc)) */ |
emilmont | 1:fdd22bb7aa52 | 1472 | R = __QADD16(xaya, xcyc); |
emilmont | 1:fdd22bb7aa52 | 1473 | |
emilmont | 1:fdd22bb7aa52 | 1474 | /* T = packed((yb + yd), (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 1475 | T = __QADD16(xbyb, xdyd); |
emilmont | 1:fdd22bb7aa52 | 1476 | |
emilmont | 1:fdd22bb7aa52 | 1477 | /* pointer updation for writing */ |
emilmont | 1:fdd22bb7aa52 | 1478 | ptr1 = ptr1 - 8u; |
emilmont | 1:fdd22bb7aa52 | 1479 | |
emilmont | 1:fdd22bb7aa52 | 1480 | |
emilmont | 1:fdd22bb7aa52 | 1481 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 1482 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 1483 | *__SIMD32(ptr1)++ = __SHADD16(R, T); |
emilmont | 1:fdd22bb7aa52 | 1484 | |
emilmont | 1:fdd22bb7aa52 | 1485 | /* T = packed((yb + yd), (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 1486 | T = __QADD16(xbyb, xdyd); |
emilmont | 1:fdd22bb7aa52 | 1487 | |
emilmont | 1:fdd22bb7aa52 | 1488 | /* xc' = (xa-xb+xc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1489 | /* yc' = (ya-yb+yc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1490 | *__SIMD32(ptr1)++ = __SHSUB16(R, T); |
emilmont | 1:fdd22bb7aa52 | 1491 | |
emilmont | 1:fdd22bb7aa52 | 1492 | /* S = packed((ya - yc), (xa - xc)) */ |
emilmont | 1:fdd22bb7aa52 | 1493 | S = __QSUB16(xaya, xcyc); |
emilmont | 1:fdd22bb7aa52 | 1494 | |
emilmont | 1:fdd22bb7aa52 | 1495 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1496 | /* T = packed( (yb - yd), (xb - xd)) */ |
emilmont | 1:fdd22bb7aa52 | 1497 | U = __QSUB16(xbyb, xdyd); |
emilmont | 1:fdd22bb7aa52 | 1498 | |
emilmont | 1:fdd22bb7aa52 | 1499 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 1500 | |
emilmont | 1:fdd22bb7aa52 | 1501 | /* xb' = (xa+yb-xc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1502 | /* yb' = (ya-xb-yc+xd) */ |
emilmont | 1:fdd22bb7aa52 | 1503 | *__SIMD32(ptr1)++ = __SHASX(S, U); |
emilmont | 1:fdd22bb7aa52 | 1504 | |
emilmont | 1:fdd22bb7aa52 | 1505 | |
emilmont | 1:fdd22bb7aa52 | 1506 | /* xd' = (xa-yb-xc+yd) */ |
emilmont | 1:fdd22bb7aa52 | 1507 | /* yd' = (ya+xb-yc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1508 | *__SIMD32(ptr1)++ = __SHSAX(S, U); |
emilmont | 1:fdd22bb7aa52 | 1509 | |
emilmont | 1:fdd22bb7aa52 | 1510 | #else |
emilmont | 1:fdd22bb7aa52 | 1511 | |
emilmont | 1:fdd22bb7aa52 | 1512 | /* xb' = (xa+yb-xc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1513 | /* yb' = (ya-xb-yc+xd) */ |
emilmont | 1:fdd22bb7aa52 | 1514 | *__SIMD32(ptr1)++ = __SHSAX(S, U); |
emilmont | 1:fdd22bb7aa52 | 1515 | |
emilmont | 1:fdd22bb7aa52 | 1516 | |
emilmont | 1:fdd22bb7aa52 | 1517 | /* xd' = (xa-yb-xc+yd) */ |
emilmont | 1:fdd22bb7aa52 | 1518 | /* yd' = (ya+xb-yc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1519 | *__SIMD32(ptr1)++ = __SHASX(S, U); |
emilmont | 1:fdd22bb7aa52 | 1520 | |
emilmont | 1:fdd22bb7aa52 | 1521 | |
emilmont | 1:fdd22bb7aa52 | 1522 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 1523 | |
emilmont | 1:fdd22bb7aa52 | 1524 | } while(--j); |
emilmont | 1:fdd22bb7aa52 | 1525 | |
emilmont | 1:fdd22bb7aa52 | 1526 | /* end of last stage process */ |
emilmont | 1:fdd22bb7aa52 | 1527 | |
emilmont | 1:fdd22bb7aa52 | 1528 | /* output is in 11.5(q5) format for the 1024 point */ |
emilmont | 1:fdd22bb7aa52 | 1529 | /* output is in 9.7(q7) format for the 256 point */ |
emilmont | 1:fdd22bb7aa52 | 1530 | /* output is in 7.9(q9) format for the 64 point */ |
emilmont | 1:fdd22bb7aa52 | 1531 | /* output is in 5.11(q11) format for the 16 point */ |
emilmont | 1:fdd22bb7aa52 | 1532 | |
emilmont | 1:fdd22bb7aa52 | 1533 | |
emilmont | 1:fdd22bb7aa52 | 1534 | #else |
emilmont | 1:fdd22bb7aa52 | 1535 | |
emilmont | 1:fdd22bb7aa52 | 1536 | /* Run the below code for Cortex-M0 */ |
emilmont | 1:fdd22bb7aa52 | 1537 | |
emilmont | 1:fdd22bb7aa52 | 1538 | q15_t R0, R1, S0, S1, T0, T1, U0, U1; |
emilmont | 1:fdd22bb7aa52 | 1539 | q15_t Co1, Si1, Co2, Si2, Co3, Si3, out1, out2; |
emilmont | 1:fdd22bb7aa52 | 1540 | uint32_t n1, n2, ic, i0, i1, i2, i3, j, k; |
emilmont | 1:fdd22bb7aa52 | 1541 | |
emilmont | 1:fdd22bb7aa52 | 1542 | /* Total process is divided into three stages */ |
emilmont | 1:fdd22bb7aa52 | 1543 | |
emilmont | 1:fdd22bb7aa52 | 1544 | /* process first stage, middle stages, & last stage */ |
emilmont | 1:fdd22bb7aa52 | 1545 | |
emilmont | 1:fdd22bb7aa52 | 1546 | /* Initializations for the first stage */ |
emilmont | 1:fdd22bb7aa52 | 1547 | n2 = fftLen; |
emilmont | 1:fdd22bb7aa52 | 1548 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 1549 | |
emilmont | 1:fdd22bb7aa52 | 1550 | /* n2 = fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 1551 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 1552 | |
emilmont | 1:fdd22bb7aa52 | 1553 | /* Index for twiddle coefficient */ |
emilmont | 1:fdd22bb7aa52 | 1554 | ic = 0u; |
emilmont | 1:fdd22bb7aa52 | 1555 | |
emilmont | 1:fdd22bb7aa52 | 1556 | /* Index for input read and output write */ |
emilmont | 1:fdd22bb7aa52 | 1557 | i0 = 0u; |
emilmont | 1:fdd22bb7aa52 | 1558 | |
emilmont | 1:fdd22bb7aa52 | 1559 | j = n2; |
emilmont | 1:fdd22bb7aa52 | 1560 | |
emilmont | 1:fdd22bb7aa52 | 1561 | /* Input is in 1.15(q15) format */ |
emilmont | 1:fdd22bb7aa52 | 1562 | |
emilmont | 1:fdd22bb7aa52 | 1563 | /* Start of first stage process */ |
emilmont | 1:fdd22bb7aa52 | 1564 | do |
emilmont | 1:fdd22bb7aa52 | 1565 | { |
emilmont | 1:fdd22bb7aa52 | 1566 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 1567 | |
emilmont | 1:fdd22bb7aa52 | 1568 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 1569 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 1570 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 1571 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 1572 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 1573 | |
emilmont | 1:fdd22bb7aa52 | 1574 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1575 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 1576 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1577 | T0 = pSrc16[i0 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1578 | T1 = pSrc16[(i0 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1579 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 1580 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1581 | S0 = pSrc16[i2 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1582 | S1 = pSrc16[(i2 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1583 | |
emilmont | 1:fdd22bb7aa52 | 1584 | /* R0 = (ya + yc), R1 = (xa + xc) */ |
emilmont | 1:fdd22bb7aa52 | 1585 | R0 = __SSAT(T0 + S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1586 | R1 = __SSAT(T1 + S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1587 | /* S0 = (ya - yc), S1 = (xa - xc) */ |
emilmont | 1:fdd22bb7aa52 | 1588 | S0 = __SSAT(T0 - S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1589 | S1 = __SSAT(T1 - S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1590 | |
emilmont | 1:fdd22bb7aa52 | 1591 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1592 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 1593 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1594 | T0 = pSrc16[i1 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1595 | T1 = pSrc16[(i1 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1596 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1597 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 1598 | U0 = pSrc16[i3 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1599 | U1 = pSrc16[(i3 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1600 | |
emilmont | 1:fdd22bb7aa52 | 1601 | /* T0 = (yb + yd), T1 = (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 1602 | T0 = __SSAT(T0 + U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1603 | T1 = __SSAT(T1 + U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1604 | |
emilmont | 1:fdd22bb7aa52 | 1605 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 1606 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 1607 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 1608 | pSrc16[i0 * 2u] = (R0 >> 1u) + (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1609 | pSrc16[(i0 * 2u) + 1u] = (R1 >> 1u) + (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1610 | |
emilmont | 1:fdd22bb7aa52 | 1611 | /* R0 = (ya + yc) - (yb + yd), R1 = (xa + xc)- (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 1612 | R0 = __SSAT(R0 - T0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1613 | R1 = __SSAT(R1 - T1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1614 | /* co2 & si2 are read from Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 1615 | Co2 = pCoef16[2u * ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1616 | Si2 = pCoef16[(2u * ic * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1617 | /* xc' = (xa-xb+xc-xd)* co2 - (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1618 | out1 = (short) ((Co2 * R0 - Si2 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1619 | /* yc' = (ya-yb+yc-yd)* co2 + (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1620 | out2 = (short) ((Si2 * R0 + Co2 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1621 | |
emilmont | 1:fdd22bb7aa52 | 1622 | /* Reading i0+fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 1623 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 1624 | /* T0 = yb, T1 = xb */ |
emilmont | 1:fdd22bb7aa52 | 1625 | T0 = pSrc16[i1 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1626 | T1 = pSrc16[(i1 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1627 | |
emilmont | 1:fdd22bb7aa52 | 1628 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1629 | /* writing output(xc', yc') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 1630 | pSrc16[i1 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 1631 | pSrc16[(i1 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 1632 | |
emilmont | 1:fdd22bb7aa52 | 1633 | /* Butterfly calculations */ |
emilmont | 1:fdd22bb7aa52 | 1634 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 1635 | /* U0 = yd, U1 = xd) */ |
emilmont | 1:fdd22bb7aa52 | 1636 | U0 = pSrc16[i3 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1637 | U1 = pSrc16[(i3 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1638 | |
emilmont | 1:fdd22bb7aa52 | 1639 | /* T0 = yb-yd, T1 = xb-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1640 | T0 = __SSAT(T0 - U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1641 | T1 = __SSAT(T1 - U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1642 | /* R0 = (ya-yc) - (xb- xd) , R1 = (xa-xc) + (yb-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1643 | R0 = (short) __SSAT((q31_t) (S0 + T1), 16); |
emilmont | 1:fdd22bb7aa52 | 1644 | R1 = (short) __SSAT((q31_t) (S1 - T0), 16); |
emilmont | 1:fdd22bb7aa52 | 1645 | /* S = (ya-yc) + (xb- xd), S1 = (xa-xc) - (yb-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1646 | S0 = (short) __SSAT((q31_t) (S0 - T1), 16); |
emilmont | 1:fdd22bb7aa52 | 1647 | S1 = (short) __SSAT((q31_t) (S1 + T0), 16); |
emilmont | 1:fdd22bb7aa52 | 1648 | |
emilmont | 1:fdd22bb7aa52 | 1649 | /* co1 & si1 are read from Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 1650 | Co1 = pCoef16[ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1651 | Si1 = pCoef16[(ic * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1652 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 1653 | /* xb' = (xa-yb-xc+yd)* co1 - (ya+xb-yc-xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1654 | out1 = (short) ((Co1 * S0 - Si1 * S1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1655 | /* yb' = (ya+xb-yc-xd)* co1 + (xa-yb-xc+yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1656 | out2 = (short) ((Si1 * S0 + Co1 * S1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1657 | /* writing output(xb', yb') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 1658 | pSrc16[i2 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 1659 | pSrc16[(i2 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 1660 | |
emilmont | 1:fdd22bb7aa52 | 1661 | /* Co3 & si3 are read from Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 1662 | Co3 = pCoef16[3u * ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1663 | Si3 = pCoef16[(3u * ic * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1664 | /* Butterfly process for the i0+3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1665 | /* xd' = (xa+yb-xc-yd)* Co3 - (ya-xb-yc+xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1666 | out1 = (short) ((Co3 * R0 - Si3 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1667 | /* yd' = (ya-xb-yc+xd)* Co3 + (xa+yb-xc-yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1668 | out2 = (short) ((Si3 * R0 + Co3 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1669 | /* writing output(xd', yd') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 1670 | pSrc16[i3 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 1671 | pSrc16[(i3 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 1672 | |
emilmont | 1:fdd22bb7aa52 | 1673 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 1674 | ic = ic + twidCoefModifier; |
emilmont | 1:fdd22bb7aa52 | 1675 | |
emilmont | 1:fdd22bb7aa52 | 1676 | /* Updating input index */ |
emilmont | 1:fdd22bb7aa52 | 1677 | i0 = i0 + 1u; |
emilmont | 1:fdd22bb7aa52 | 1678 | |
emilmont | 1:fdd22bb7aa52 | 1679 | } while(--j); |
emilmont | 1:fdd22bb7aa52 | 1680 | |
emilmont | 1:fdd22bb7aa52 | 1681 | /* End of first stage process */ |
emilmont | 1:fdd22bb7aa52 | 1682 | |
emilmont | 1:fdd22bb7aa52 | 1683 | /* data is in 4.11(q11) format */ |
emilmont | 1:fdd22bb7aa52 | 1684 | |
emilmont | 1:fdd22bb7aa52 | 1685 | |
emilmont | 1:fdd22bb7aa52 | 1686 | /* Start of Middle stage process */ |
emilmont | 1:fdd22bb7aa52 | 1687 | |
emilmont | 1:fdd22bb7aa52 | 1688 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 1689 | twidCoefModifier <<= 2u; |
emilmont | 1:fdd22bb7aa52 | 1690 | |
emilmont | 1:fdd22bb7aa52 | 1691 | /* Calculation of Middle stage */ |
emilmont | 1:fdd22bb7aa52 | 1692 | for (k = fftLen / 4u; k > 4u; k >>= 2u) |
emilmont | 1:fdd22bb7aa52 | 1693 | { |
emilmont | 1:fdd22bb7aa52 | 1694 | /* Initializations for the middle stage */ |
emilmont | 1:fdd22bb7aa52 | 1695 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 1696 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 1697 | ic = 0u; |
emilmont | 1:fdd22bb7aa52 | 1698 | |
emilmont | 1:fdd22bb7aa52 | 1699 | for (j = 0u; j <= (n2 - 1u); j++) |
emilmont | 1:fdd22bb7aa52 | 1700 | { |
emilmont | 1:fdd22bb7aa52 | 1701 | /* index calculation for the coefficients */ |
emilmont | 1:fdd22bb7aa52 | 1702 | Co1 = pCoef16[ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1703 | Si1 = pCoef16[(ic * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1704 | Co2 = pCoef16[2u * ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1705 | Si2 = pCoef16[2u * ic * 2u + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1706 | Co3 = pCoef16[3u * ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1707 | Si3 = pCoef16[(3u * ic * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1708 | |
emilmont | 1:fdd22bb7aa52 | 1709 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 1710 | ic = ic + twidCoefModifier; |
emilmont | 1:fdd22bb7aa52 | 1711 | |
emilmont | 1:fdd22bb7aa52 | 1712 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 1713 | for (i0 = j; i0 < fftLen; i0 += n1) |
emilmont | 1:fdd22bb7aa52 | 1714 | { |
emilmont | 1:fdd22bb7aa52 | 1715 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 1716 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 1717 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 1718 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 1719 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 1720 | |
emilmont | 1:fdd22bb7aa52 | 1721 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1722 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1723 | T0 = pSrc16[i0 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1724 | T1 = pSrc16[(i0 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1725 | |
emilmont | 1:fdd22bb7aa52 | 1726 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1727 | S0 = pSrc16[i2 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1728 | S1 = pSrc16[(i2 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1729 | |
emilmont | 1:fdd22bb7aa52 | 1730 | |
emilmont | 1:fdd22bb7aa52 | 1731 | /* R0 = (ya + yc), R1 = (xa + xc) */ |
emilmont | 1:fdd22bb7aa52 | 1732 | R0 = __SSAT(T0 + S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1733 | R1 = __SSAT(T1 + S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1734 | /* S0 = (ya - yc), S1 = (xa - xc) */ |
emilmont | 1:fdd22bb7aa52 | 1735 | S0 = __SSAT(T0 - S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1736 | S1 = __SSAT(T1 - S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1737 | |
emilmont | 1:fdd22bb7aa52 | 1738 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1739 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1740 | T0 = pSrc16[i1 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1741 | T1 = pSrc16[(i1 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1742 | |
emilmont | 1:fdd22bb7aa52 | 1743 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1744 | U0 = pSrc16[i3 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1745 | U1 = pSrc16[(i3 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1746 | |
emilmont | 1:fdd22bb7aa52 | 1747 | /* T0 = (yb + yd), T1 = (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 1748 | T0 = __SSAT(T0 + U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1749 | T1 = __SSAT(T1 + U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1750 | |
emilmont | 1:fdd22bb7aa52 | 1751 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 1752 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 1753 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 1754 | pSrc16[i0 * 2u] = ((R0 >> 1u) + (T0 >> 1u)) >> 1u; |
emilmont | 1:fdd22bb7aa52 | 1755 | pSrc16[(i0 * 2u) + 1u] = ((R1 >> 1u) + (T1 >> 1u)) >> 1u; |
emilmont | 1:fdd22bb7aa52 | 1756 | |
emilmont | 1:fdd22bb7aa52 | 1757 | /* R0 = (ya + yc) - (yb + yd), R1 = (xa + xc) - (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 1758 | R0 = (R0 >> 1u) - (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1759 | R1 = (R1 >> 1u) - (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1760 | |
emilmont | 1:fdd22bb7aa52 | 1761 | /* (ya-yb+yc-yd)* (si2) - (xa-xb+xc-xd)* co2 */ |
emilmont | 1:fdd22bb7aa52 | 1762 | out1 = (short) ((Co2 * R0 - Si2 * R1) >> 16); |
emilmont | 1:fdd22bb7aa52 | 1763 | /* (ya-yb+yc-yd)* co2 + (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1764 | out2 = (short) ((Si2 * R0 + Co2 * R1) >> 16); |
emilmont | 1:fdd22bb7aa52 | 1765 | |
emilmont | 1:fdd22bb7aa52 | 1766 | /* Reading i0+3fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 1767 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1768 | T0 = pSrc16[i1 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1769 | T1 = pSrc16[(i1 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1770 | |
emilmont | 1:fdd22bb7aa52 | 1771 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1772 | /* xc' = (xa-xb+xc-xd)* co2 - (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1773 | /* yc' = (ya-yb+yc-yd)* co2 + (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1774 | pSrc16[i1 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 1775 | pSrc16[(i1 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 1776 | |
emilmont | 1:fdd22bb7aa52 | 1777 | /* Butterfly calculations */ |
emilmont | 1:fdd22bb7aa52 | 1778 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1779 | U0 = pSrc16[i3 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1780 | U1 = pSrc16[(i3 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1781 | |
emilmont | 1:fdd22bb7aa52 | 1782 | /* T0 = yb-yd, T1 = xb-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1783 | T0 = __SSAT(T0 - U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1784 | T1 = __SSAT(T1 - U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1785 | |
emilmont | 1:fdd22bb7aa52 | 1786 | /* R0 = (ya-yc) - (xb- xd) , R1 = (xa-xc) + (yb-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1787 | R0 = (S0 >> 1u) + (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1788 | R1 = (S1 >> 1u) - (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1789 | |
emilmont | 1:fdd22bb7aa52 | 1790 | /* S1 = (ya-yc) + (xb- xd), S1 = (xa-xc) - (yb-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1791 | S0 = (S0 >> 1u) - (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1792 | S1 = (S1 >> 1u) + (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1793 | |
emilmont | 1:fdd22bb7aa52 | 1794 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 1795 | out1 = (short) ((Co1 * S0 - Si1 * S1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1796 | out2 = (short) ((Si1 * S0 + Co1 * S1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1797 | /* xb' = (xa-yb-xc+yd)* co1 - (ya+xb-yc-xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1798 | /* yb' = (ya+xb-yc-xd)* co1 + (xa-yb-xc+yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1799 | pSrc16[i2 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 1800 | pSrc16[(i2 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 1801 | |
emilmont | 1:fdd22bb7aa52 | 1802 | /* Butterfly process for the i0+3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1803 | out1 = (short) ((Co3 * R0 - Si3 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1804 | |
emilmont | 1:fdd22bb7aa52 | 1805 | out2 = (short) ((Si3 * R0 + Co3 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1806 | /* xd' = (xa+yb-xc-yd)* Co3 - (ya-xb-yc+xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1807 | /* yd' = (ya-xb-yc+xd)* Co3 + (xa+yb-xc-yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1808 | pSrc16[i3 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 1809 | pSrc16[(i3 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 1810 | |
emilmont | 1:fdd22bb7aa52 | 1811 | |
emilmont | 1:fdd22bb7aa52 | 1812 | } |
emilmont | 1:fdd22bb7aa52 | 1813 | } |
emilmont | 1:fdd22bb7aa52 | 1814 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 1815 | twidCoefModifier <<= 2u; |
emilmont | 1:fdd22bb7aa52 | 1816 | } |
emilmont | 1:fdd22bb7aa52 | 1817 | /* End of Middle stages process */ |
emilmont | 1:fdd22bb7aa52 | 1818 | |
emilmont | 1:fdd22bb7aa52 | 1819 | |
emilmont | 1:fdd22bb7aa52 | 1820 | /* data is in 10.6(q6) format for the 1024 point */ |
emilmont | 1:fdd22bb7aa52 | 1821 | /* data is in 8.8(q8) format for the 256 point */ |
emilmont | 1:fdd22bb7aa52 | 1822 | /* data is in 6.10(q10) format for the 64 point */ |
emilmont | 1:fdd22bb7aa52 | 1823 | /* data is in 4.12(q12) format for the 16 point */ |
emilmont | 1:fdd22bb7aa52 | 1824 | |
emilmont | 1:fdd22bb7aa52 | 1825 | /* start of last stage process */ |
emilmont | 1:fdd22bb7aa52 | 1826 | |
emilmont | 1:fdd22bb7aa52 | 1827 | |
emilmont | 1:fdd22bb7aa52 | 1828 | /* Initializations for the last stage */ |
emilmont | 1:fdd22bb7aa52 | 1829 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 1830 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 1831 | |
emilmont | 1:fdd22bb7aa52 | 1832 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 1833 | for (i0 = 0u; i0 <= (fftLen - n1); i0 += n1) |
emilmont | 1:fdd22bb7aa52 | 1834 | { |
emilmont | 1:fdd22bb7aa52 | 1835 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 1836 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 1837 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 1838 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 1839 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 1840 | |
emilmont | 1:fdd22bb7aa52 | 1841 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1842 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1843 | T0 = pSrc16[i0 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1844 | T1 = pSrc16[(i0 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1845 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1846 | S0 = pSrc16[i2 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1847 | S1 = pSrc16[(i2 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1848 | |
emilmont | 1:fdd22bb7aa52 | 1849 | /* R0 = (ya + yc), R1 = (xa + xc) */ |
emilmont | 1:fdd22bb7aa52 | 1850 | R0 = __SSAT(T0 + S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1851 | R1 = __SSAT(T1 + S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1852 | /* S0 = (ya - yc), S1 = (xa - xc) */ |
emilmont | 1:fdd22bb7aa52 | 1853 | S0 = __SSAT(T0 - S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1854 | S1 = __SSAT(T1 - S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1855 | |
emilmont | 1:fdd22bb7aa52 | 1856 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1857 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1858 | T0 = pSrc16[i1 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1859 | T1 = pSrc16[(i1 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1860 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1861 | U0 = pSrc16[i3 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1862 | U1 = pSrc16[(i3 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1863 | |
emilmont | 1:fdd22bb7aa52 | 1864 | /* T0 = (yb + yd), T1 = (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 1865 | T0 = __SSAT(T0 + U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1866 | T1 = __SSAT(T1 + U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1867 | |
emilmont | 1:fdd22bb7aa52 | 1868 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 1869 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 1870 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 1871 | pSrc16[i0 * 2u] = (R0 >> 1u) + (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1872 | pSrc16[(i0 * 2u) + 1u] = (R1 >> 1u) + (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1873 | |
emilmont | 1:fdd22bb7aa52 | 1874 | /* R0 = (ya + yc) - (yb + yd), R1 = (xa + xc) - (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 1875 | R0 = (R0 >> 1u) - (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1876 | R1 = (R1 >> 1u) - (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1877 | |
emilmont | 1:fdd22bb7aa52 | 1878 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1879 | T0 = pSrc16[i1 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1880 | T1 = pSrc16[(i1 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1881 | |
emilmont | 1:fdd22bb7aa52 | 1882 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1883 | /* xc' = (xa-xb+xc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1884 | /* yc' = (ya-yb+yc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1885 | pSrc16[i1 * 2u] = R0; |
emilmont | 1:fdd22bb7aa52 | 1886 | pSrc16[(i1 * 2u) + 1u] = R1; |
emilmont | 1:fdd22bb7aa52 | 1887 | |
emilmont | 1:fdd22bb7aa52 | 1888 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1889 | U0 = pSrc16[i3 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1890 | U1 = pSrc16[(i3 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1891 | /* T0 = (yb - yd), T1 = (xb - xd) */ |
emilmont | 1:fdd22bb7aa52 | 1892 | T0 = __SSAT(T0 - U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1893 | T1 = __SSAT(T1 - U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1894 | |
emilmont | 1:fdd22bb7aa52 | 1895 | /* writing the butterfly processed i0 + fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 1896 | /* xb' = (xa-yb-xc+yd) */ |
emilmont | 1:fdd22bb7aa52 | 1897 | /* yb' = (ya+xb-yc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1898 | pSrc16[i2 * 2u] = (S0 >> 1u) - (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1899 | pSrc16[(i2 * 2u) + 1u] = (S1 >> 1u) + (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1900 | |
emilmont | 1:fdd22bb7aa52 | 1901 | |
emilmont | 1:fdd22bb7aa52 | 1902 | /* writing the butterfly processed i0 + 3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1903 | /* xd' = (xa+yb-xc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1904 | /* yd' = (ya-xb-yc+xd) */ |
emilmont | 1:fdd22bb7aa52 | 1905 | pSrc16[i3 * 2u] = (S0 >> 1u) + (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1906 | pSrc16[(i3 * 2u) + 1u] = (S1 >> 1u) - (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1907 | } |
emilmont | 1:fdd22bb7aa52 | 1908 | /* end of last stage process */ |
emilmont | 1:fdd22bb7aa52 | 1909 | |
emilmont | 1:fdd22bb7aa52 | 1910 | /* output is in 11.5(q5) format for the 1024 point */ |
emilmont | 1:fdd22bb7aa52 | 1911 | /* output is in 9.7(q7) format for the 256 point */ |
emilmont | 1:fdd22bb7aa52 | 1912 | /* output is in 7.9(q9) format for the 64 point */ |
emilmont | 1:fdd22bb7aa52 | 1913 | /* output is in 5.11(q11) format for the 16 point */ |
emilmont | 1:fdd22bb7aa52 | 1914 | |
mbed_official | 3:7a284390b0ce | 1915 | #endif /* #ifndef ARM_MATH_CM0_FAMILY */ |
emilmont | 1:fdd22bb7aa52 | 1916 | |
emilmont | 1:fdd22bb7aa52 | 1917 | } |