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CMSIS DSP library

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cmsis_dsp/SupportFunctions/arm_float_to_q7.c@2:da51fb522205, 2013-05-30 (annotated)

Committer:
emilmont
Date:
Thu May 30 17:10:11 2013 +0100
Revision:
2:da51fb522205
Parent:
1:fdd22bb7aa52
Child:
3:7a284390b0ce
Keep "cmsis-dsp" module in synch with its source

Who changed what in which revision?

UserRevisionLine numberNew contents of line
emilmont 1:fdd22bb7aa52 1 /* ----------------------------------------------------------------------------
emilmont 1:fdd22bb7aa52 2 * Copyright (C) 2010 ARM Limited. All rights reserved.
emilmont 1:fdd22bb7aa52 3 *
emilmont 1:fdd22bb7aa52 4 * $Date: 15. February 2012
emilmont 2:da51fb522205 5 * $Revision: V1.1.0
emilmont 1:fdd22bb7aa52 6 *
emilmont 2:da51fb522205 7 * Project: CMSIS DSP Library
emilmont 2:da51fb522205 8 * Title: arm_float_to_q7.c
emilmont 1:fdd22bb7aa52 9 *
emilmont 2:da51fb522205 10 * Description: Converts the elements of the floating-point vector to Q7 vector.
emilmont 1:fdd22bb7aa52 11 *
emilmont 1:fdd22bb7aa52 12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
emilmont 1:fdd22bb7aa52 13 *
emilmont 1:fdd22bb7aa52 14 * Version 1.1.0 2012/02/15
emilmont 1:fdd22bb7aa52 15 * Updated with more optimizations, bug fixes and minor API changes.
emilmont 1:fdd22bb7aa52 16 *
emilmont 1:fdd22bb7aa52 17 * Version 1.0.10 2011/7/15
emilmont 1:fdd22bb7aa52 18 * Big Endian support added and Merged M0 and M3/M4 Source code.
emilmont 1:fdd22bb7aa52 19 *
emilmont 1:fdd22bb7aa52 20 * Version 1.0.3 2010/11/29
emilmont 1:fdd22bb7aa52 21 * Re-organized the CMSIS folders and updated documentation.
emilmont 1:fdd22bb7aa52 22 *
emilmont 1:fdd22bb7aa52 23 * Version 1.0.2 2010/11/11
emilmont 1:fdd22bb7aa52 24 * Documentation updated.
emilmont 1:fdd22bb7aa52 25 *
emilmont 1:fdd22bb7aa52 26 * Version 1.0.1 2010/10/05
emilmont 1:fdd22bb7aa52 27 * Production release and review comments incorporated.
emilmont 1:fdd22bb7aa52 28 *
emilmont 1:fdd22bb7aa52 29 * Version 1.0.0 2010/09/20
emilmont 1:fdd22bb7aa52 30 * Production release and review comments incorporated.
emilmont 1:fdd22bb7aa52 31 * ---------------------------------------------------------------------------- */
emilmont 1:fdd22bb7aa52 32
emilmont 1:fdd22bb7aa52 33 #include "arm_math.h"
emilmont 1:fdd22bb7aa52 34
emilmont 1:fdd22bb7aa52 35 /**
emilmont 1:fdd22bb7aa52 36 * @ingroup groupSupport
emilmont 1:fdd22bb7aa52 37 */
emilmont 1:fdd22bb7aa52 38
emilmont 1:fdd22bb7aa52 39 /**
emilmont 1:fdd22bb7aa52 40 * @addtogroup float_to_x
emilmont 1:fdd22bb7aa52 41 * @{
emilmont 1:fdd22bb7aa52 42 */
emilmont 1:fdd22bb7aa52 43
emilmont 1:fdd22bb7aa52 44 /**
emilmont 1:fdd22bb7aa52 45 * @brief Converts the elements of the floating-point vector to Q7 vector.
emilmont 1:fdd22bb7aa52 46 * @param[in] *pSrc points to the floating-point input vector
emilmont 1:fdd22bb7aa52 47 * @param[out] *pDst points to the Q7 output vector
emilmont 1:fdd22bb7aa52 48 * @param[in] blockSize length of the input vector
emilmont 1:fdd22bb7aa52 49 * @return none.
emilmont 1:fdd22bb7aa52 50 *
emilmont 1:fdd22bb7aa52 51 *\par Description:
emilmont 1:fdd22bb7aa52 52 * \par
emilmont 1:fdd22bb7aa52 53 * The equation used for the conversion process is:
emilmont 1:fdd22bb7aa52 54 * <pre>
emilmont 2:da51fb522205 55 * pDst[n] = (q7_t)(pSrc[n] * 128); 0 <= n < blockSize.
emilmont 1:fdd22bb7aa52 56 * </pre>
emilmont 1:fdd22bb7aa52 57 * \par Scaling and Overflow Behavior:
emilmont 1:fdd22bb7aa52 58 * \par
emilmont 1:fdd22bb7aa52 59 * The function uses saturating arithmetic.
emilmont 1:fdd22bb7aa52 60 * Results outside of the allowable Q7 range [0x80 0x7F] will be saturated.
emilmont 1:fdd22bb7aa52 61 * \note
emilmont 1:fdd22bb7aa52 62 * In order to apply rounding, the library should be rebuilt with the ROUNDING macro
emilmont 1:fdd22bb7aa52 63 * defined in the preprocessor section of project options.
emilmont 1:fdd22bb7aa52 64 */
emilmont 1:fdd22bb7aa52 65
emilmont 1:fdd22bb7aa52 66
emilmont 1:fdd22bb7aa52 67 void arm_float_to_q7(
emilmont 1:fdd22bb7aa52 68 float32_t * pSrc,
emilmont 1:fdd22bb7aa52 69 q7_t * pDst,
emilmont 1:fdd22bb7aa52 70 uint32_t blockSize)
emilmont 1:fdd22bb7aa52 71 {
emilmont 1:fdd22bb7aa52 72 float32_t *pIn = pSrc; /* Src pointer */
emilmont 1:fdd22bb7aa52 73 uint32_t blkCnt; /* loop counter */
emilmont 1:fdd22bb7aa52 74
emilmont 1:fdd22bb7aa52 75 #ifdef ARM_MATH_ROUNDING
emilmont 1:fdd22bb7aa52 76
emilmont 1:fdd22bb7aa52 77 float32_t in;
emilmont 1:fdd22bb7aa52 78
emilmont 1:fdd22bb7aa52 79 #endif /* #ifdef ARM_MATH_ROUNDING */
emilmont 1:fdd22bb7aa52 80
emilmont 1:fdd22bb7aa52 81 #ifndef ARM_MATH_CM0
emilmont 1:fdd22bb7aa52 82
emilmont 1:fdd22bb7aa52 83 /* Run the below code for Cortex-M4 and Cortex-M3 */
emilmont 1:fdd22bb7aa52 84
emilmont 1:fdd22bb7aa52 85 /*loop Unrolling */
emilmont 1:fdd22bb7aa52 86 blkCnt = blockSize >> 2u;
emilmont 1:fdd22bb7aa52 87
emilmont 1:fdd22bb7aa52 88 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
emilmont 1:fdd22bb7aa52 89 ** a second loop below computes the remaining 1 to 3 samples. */
emilmont 1:fdd22bb7aa52 90 while(blkCnt > 0u)
emilmont 1:fdd22bb7aa52 91 {
emilmont 1:fdd22bb7aa52 92
emilmont 1:fdd22bb7aa52 93 #ifdef ARM_MATH_ROUNDING
emilmont 1:fdd22bb7aa52 94 /* C = A * 128 */
emilmont 1:fdd22bb7aa52 95 /* convert from float to q7 and then store the results in the destination buffer */
emilmont 1:fdd22bb7aa52 96 in = *pIn++;
emilmont 1:fdd22bb7aa52 97 in = (in * 128);
emilmont 1:fdd22bb7aa52 98 in += in > 0 ? 0.5 : -0.5;
emilmont 1:fdd22bb7aa52 99 *pDst++ = (q7_t) (__SSAT((q15_t) (in), 8));
emilmont 1:fdd22bb7aa52 100
emilmont 1:fdd22bb7aa52 101 in = *pIn++;
emilmont 1:fdd22bb7aa52 102 in = (in * 128);
emilmont 1:fdd22bb7aa52 103 in += in > 0 ? 0.5 : -0.5;
emilmont 1:fdd22bb7aa52 104 *pDst++ = (q7_t) (__SSAT((q15_t) (in), 8));
emilmont 1:fdd22bb7aa52 105
emilmont 1:fdd22bb7aa52 106 in = *pIn++;
emilmont 1:fdd22bb7aa52 107 in = (in * 128);
emilmont 1:fdd22bb7aa52 108 in += in > 0 ? 0.5 : -0.5;
emilmont 1:fdd22bb7aa52 109 *pDst++ = (q7_t) (__SSAT((q15_t) (in), 8));
emilmont 1:fdd22bb7aa52 110
emilmont 1:fdd22bb7aa52 111 in = *pIn++;
emilmont 1:fdd22bb7aa52 112 in = (in * 128);
emilmont 1:fdd22bb7aa52 113 in += in > 0 ? 0.5 : -0.5;
emilmont 1:fdd22bb7aa52 114 *pDst++ = (q7_t) (__SSAT((q15_t) (in), 8));
emilmont 1:fdd22bb7aa52 115
emilmont 1:fdd22bb7aa52 116 #else
emilmont 1:fdd22bb7aa52 117
emilmont 1:fdd22bb7aa52 118 /* C = A * 128 */
emilmont 1:fdd22bb7aa52 119 /* convert from float to q7 and then store the results in the destination buffer */
emilmont 1:fdd22bb7aa52 120 *pDst++ = __SSAT((q31_t) (*pIn++ * 128.0f), 8);
emilmont 1:fdd22bb7aa52 121 *pDst++ = __SSAT((q31_t) (*pIn++ * 128.0f), 8);
emilmont 1:fdd22bb7aa52 122 *pDst++ = __SSAT((q31_t) (*pIn++ * 128.0f), 8);
emilmont 1:fdd22bb7aa52 123 *pDst++ = __SSAT((q31_t) (*pIn++ * 128.0f), 8);
emilmont 1:fdd22bb7aa52 124
emilmont 1:fdd22bb7aa52 125 #endif /* #ifdef ARM_MATH_ROUNDING */
emilmont 1:fdd22bb7aa52 126
emilmont 1:fdd22bb7aa52 127 /* Decrement the loop counter */
emilmont 1:fdd22bb7aa52 128 blkCnt--;
emilmont 1:fdd22bb7aa52 129 }
emilmont 1:fdd22bb7aa52 130
emilmont 1:fdd22bb7aa52 131 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
emilmont 1:fdd22bb7aa52 132 ** No loop unrolling is used. */
emilmont 1:fdd22bb7aa52 133 blkCnt = blockSize % 0x4u;
emilmont 1:fdd22bb7aa52 134
emilmont 1:fdd22bb7aa52 135 while(blkCnt > 0u)
emilmont 1:fdd22bb7aa52 136 {
emilmont 1:fdd22bb7aa52 137
emilmont 1:fdd22bb7aa52 138 #ifdef ARM_MATH_ROUNDING
emilmont 1:fdd22bb7aa52 139 /* C = A * 128 */
emilmont 1:fdd22bb7aa52 140 /* convert from float to q7 and then store the results in the destination buffer */
emilmont 1:fdd22bb7aa52 141 in = *pIn++;
emilmont 1:fdd22bb7aa52 142 in = (in * 128);
emilmont 1:fdd22bb7aa52 143 in += in > 0 ? 0.5 : -0.5;
emilmont 1:fdd22bb7aa52 144 *pDst++ = (q7_t) (__SSAT((q15_t) (in), 8));
emilmont 1:fdd22bb7aa52 145
emilmont 1:fdd22bb7aa52 146 #else
emilmont 1:fdd22bb7aa52 147
emilmont 1:fdd22bb7aa52 148 /* C = A * 128 */
emilmont 1:fdd22bb7aa52 149 /* convert from float to q7 and then store the results in the destination buffer */
emilmont 1:fdd22bb7aa52 150 *pDst++ = __SSAT((q31_t) (*pIn++ * 128.0f), 8);
emilmont 1:fdd22bb7aa52 151
emilmont 1:fdd22bb7aa52 152 #endif /* #ifdef ARM_MATH_ROUNDING */
emilmont 1:fdd22bb7aa52 153
emilmont 1:fdd22bb7aa52 154 /* Decrement the loop counter */
emilmont 1:fdd22bb7aa52 155 blkCnt--;
emilmont 1:fdd22bb7aa52 156 }
emilmont 1:fdd22bb7aa52 157
emilmont 1:fdd22bb7aa52 158
emilmont 1:fdd22bb7aa52 159 #else
emilmont 1:fdd22bb7aa52 160
emilmont 1:fdd22bb7aa52 161 /* Run the below code for Cortex-M0 */
emilmont 1:fdd22bb7aa52 162
emilmont 1:fdd22bb7aa52 163
emilmont 1:fdd22bb7aa52 164 /* Loop over blockSize number of values */
emilmont 1:fdd22bb7aa52 165 blkCnt = blockSize;
emilmont 1:fdd22bb7aa52 166
emilmont 1:fdd22bb7aa52 167 while(blkCnt > 0u)
emilmont 1:fdd22bb7aa52 168 {
emilmont 1:fdd22bb7aa52 169 #ifdef ARM_MATH_ROUNDING
emilmont 1:fdd22bb7aa52 170 /* C = A * 128 */
emilmont 1:fdd22bb7aa52 171 /* convert from float to q7 and then store the results in the destination buffer */
emilmont 1:fdd22bb7aa52 172 in = *pIn++;
emilmont 1:fdd22bb7aa52 173 in = (in * 128.0f);
emilmont 1:fdd22bb7aa52 174 in += in > 0 ? 0.5f : -0.5f;
emilmont 1:fdd22bb7aa52 175 *pDst++ = (q7_t) (__SSAT((q31_t) (in), 8));
emilmont 1:fdd22bb7aa52 176
emilmont 1:fdd22bb7aa52 177 #else
emilmont 1:fdd22bb7aa52 178
emilmont 1:fdd22bb7aa52 179 /* C = A * 128 */
emilmont 1:fdd22bb7aa52 180 /* convert from float to q7 and then store the results in the destination buffer */
emilmont 1:fdd22bb7aa52 181 *pDst++ = (q7_t) __SSAT((q31_t) (*pIn++ * 128.0f), 8);
emilmont 1:fdd22bb7aa52 182
emilmont 1:fdd22bb7aa52 183 #endif /* #ifdef ARM_MATH_ROUNDING */
emilmont 1:fdd22bb7aa52 184
emilmont 1:fdd22bb7aa52 185 /* Decrement the loop counter */
emilmont 1:fdd22bb7aa52 186 blkCnt--;
emilmont 1:fdd22bb7aa52 187 }
emilmont 1:fdd22bb7aa52 188
emilmont 1:fdd22bb7aa52 189 #endif /* #ifndef ARM_MATH_CM0 */
emilmont 1:fdd22bb7aa52 190
emilmont 1:fdd22bb7aa52 191 }
emilmont 1:fdd22bb7aa52 192
emilmont 1:fdd22bb7aa52 193 /**
emilmont 1:fdd22bb7aa52 194 * @} end of float_to_x group
emilmont 1:fdd22bb7aa52 195 */