Laxmi Kant Tiwari / mbed-dsp

Important changes to repositories hosted on mbed.com

Mbed hosted mercurial repositories are deprecated and are due to be permanently deleted in July 2026.

To keep a copy of this software download the repository Zip archive or clone locally using Mercurial.

It is also possible to export all your personal repositories from the account settings page.

Fork of mbed-dsp by mbed official

cmsis_dsp/BasicMathFunctions/arm_scale_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_scale_q7.c
emilmont 1:fdd22bb7aa52 9 *
emilmont 2:da51fb522205 10 * Description: Multiplies a Q7 vector by a scalar.
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 * Version 0.0.7 2010/06/10
emilmont 1:fdd22bb7aa52 33 * Misra-C changes done
emilmont 1:fdd22bb7aa52 34 * -------------------------------------------------------------------- */
emilmont 1:fdd22bb7aa52 35
emilmont 1:fdd22bb7aa52 36 #include "arm_math.h"
emilmont 1:fdd22bb7aa52 37
emilmont 1:fdd22bb7aa52 38 /**
emilmont 1:fdd22bb7aa52 39 * @ingroup groupMath
emilmont 1:fdd22bb7aa52 40 */
emilmont 1:fdd22bb7aa52 41
emilmont 1:fdd22bb7aa52 42 /**
emilmont 1:fdd22bb7aa52 43 * @addtogroup scale
emilmont 1:fdd22bb7aa52 44 * @{
emilmont 1:fdd22bb7aa52 45 */
emilmont 1:fdd22bb7aa52 46
emilmont 1:fdd22bb7aa52 47 /**
emilmont 1:fdd22bb7aa52 48 * @brief Multiplies a Q7 vector by a scalar.
emilmont 1:fdd22bb7aa52 49 * @param[in] *pSrc points to the input vector
emilmont 1:fdd22bb7aa52 50 * @param[in] scaleFract fractional portion of the scale value
emilmont 1:fdd22bb7aa52 51 * @param[in] shift number of bits to shift the result by
emilmont 1:fdd22bb7aa52 52 * @param[out] *pDst points to the output vector
emilmont 1:fdd22bb7aa52 53 * @param[in] blockSize number of samples in the vector
emilmont 1:fdd22bb7aa52 54 * @return none.
emilmont 1:fdd22bb7aa52 55 *
emilmont 1:fdd22bb7aa52 56 * <b>Scaling and Overflow Behavior:</b>
emilmont 1:fdd22bb7aa52 57 * \par
emilmont 1:fdd22bb7aa52 58 * The input data <code>*pSrc</code> and <code>scaleFract</code> are in 1.7 format.
emilmont 1:fdd22bb7aa52 59 * These are multiplied to yield a 2.14 intermediate result and this is shifted with saturation to 1.7 format.
emilmont 1:fdd22bb7aa52 60 */
emilmont 1:fdd22bb7aa52 61
emilmont 1:fdd22bb7aa52 62 void arm_scale_q7(
emilmont 1:fdd22bb7aa52 63 q7_t * pSrc,
emilmont 1:fdd22bb7aa52 64 q7_t scaleFract,
emilmont 1:fdd22bb7aa52 65 int8_t shift,
emilmont 1:fdd22bb7aa52 66 q7_t * pDst,
emilmont 1:fdd22bb7aa52 67 uint32_t blockSize)
emilmont 1:fdd22bb7aa52 68 {
emilmont 1:fdd22bb7aa52 69 int8_t kShift = 7 - shift; /* shift to apply after scaling */
emilmont 1:fdd22bb7aa52 70 uint32_t blkCnt; /* loop counter */
emilmont 1:fdd22bb7aa52 71
emilmont 1:fdd22bb7aa52 72 #ifndef ARM_MATH_CM0
emilmont 1:fdd22bb7aa52 73
emilmont 1:fdd22bb7aa52 74 /* Run the below code for Cortex-M4 and Cortex-M3 */
emilmont 1:fdd22bb7aa52 75 q7_t in1, in2, in3, in4, out1, out2, out3, out4; /* Temporary variables to store input & output */
emilmont 1:fdd22bb7aa52 76
emilmont 1:fdd22bb7aa52 77
emilmont 1:fdd22bb7aa52 78 /*loop Unrolling */
emilmont 1:fdd22bb7aa52 79 blkCnt = blockSize >> 2u;
emilmont 1:fdd22bb7aa52 80
emilmont 1:fdd22bb7aa52 81
emilmont 1:fdd22bb7aa52 82 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
emilmont 1:fdd22bb7aa52 83 ** a second loop below computes the remaining 1 to 3 samples. */
emilmont 1:fdd22bb7aa52 84 while(blkCnt > 0u)
emilmont 1:fdd22bb7aa52 85 {
emilmont 1:fdd22bb7aa52 86 /* Reading 4 inputs from memory */
emilmont 1:fdd22bb7aa52 87 in1 = *pSrc++;
emilmont 1:fdd22bb7aa52 88 in2 = *pSrc++;
emilmont 1:fdd22bb7aa52 89 in3 = *pSrc++;
emilmont 1:fdd22bb7aa52 90 in4 = *pSrc++;
emilmont 1:fdd22bb7aa52 91
emilmont 1:fdd22bb7aa52 92 /* C = A * scale */
emilmont 1:fdd22bb7aa52 93 /* Scale the inputs and then store the results in the temporary variables. */
emilmont 1:fdd22bb7aa52 94 out1 = (q7_t) (__SSAT(((in1) * scaleFract) >> kShift, 8));
emilmont 1:fdd22bb7aa52 95 out2 = (q7_t) (__SSAT(((in2) * scaleFract) >> kShift, 8));
emilmont 1:fdd22bb7aa52 96 out3 = (q7_t) (__SSAT(((in3) * scaleFract) >> kShift, 8));
emilmont 1:fdd22bb7aa52 97 out4 = (q7_t) (__SSAT(((in4) * scaleFract) >> kShift, 8));
emilmont 1:fdd22bb7aa52 98
emilmont 1:fdd22bb7aa52 99 /* Packing the individual outputs into 32bit and storing in
emilmont 1:fdd22bb7aa52 100 * destination buffer in single write */
emilmont 1:fdd22bb7aa52 101 *__SIMD32(pDst)++ = __PACKq7(out1, out2, out3, out4);
emilmont 1:fdd22bb7aa52 102
emilmont 1:fdd22bb7aa52 103 /* Decrement the loop counter */
emilmont 1:fdd22bb7aa52 104 blkCnt--;
emilmont 1:fdd22bb7aa52 105 }
emilmont 1:fdd22bb7aa52 106
emilmont 1:fdd22bb7aa52 107 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
emilmont 1:fdd22bb7aa52 108 ** No loop unrolling is used. */
emilmont 1:fdd22bb7aa52 109 blkCnt = blockSize % 0x4u;
emilmont 1:fdd22bb7aa52 110
emilmont 1:fdd22bb7aa52 111 while(blkCnt > 0u)
emilmont 1:fdd22bb7aa52 112 {
emilmont 1:fdd22bb7aa52 113 /* C = A * scale */
emilmont 1:fdd22bb7aa52 114 /* Scale the input and then store the result in the destination buffer. */
emilmont 1:fdd22bb7aa52 115 *pDst++ = (q7_t) (__SSAT(((*pSrc++) * scaleFract) >> kShift, 8));
emilmont 1:fdd22bb7aa52 116
emilmont 1:fdd22bb7aa52 117 /* Decrement the loop counter */
emilmont 1:fdd22bb7aa52 118 blkCnt--;
emilmont 1:fdd22bb7aa52 119 }
emilmont 1:fdd22bb7aa52 120
emilmont 1:fdd22bb7aa52 121 #else
emilmont 1:fdd22bb7aa52 122
emilmont 1:fdd22bb7aa52 123 /* Run the below code for Cortex-M0 */
emilmont 1:fdd22bb7aa52 124
emilmont 1:fdd22bb7aa52 125 /* Initialize blkCnt with number of samples */
emilmont 1:fdd22bb7aa52 126 blkCnt = blockSize;
emilmont 1:fdd22bb7aa52 127
emilmont 1:fdd22bb7aa52 128 while(blkCnt > 0u)
emilmont 1:fdd22bb7aa52 129 {
emilmont 1:fdd22bb7aa52 130 /* C = A * scale */
emilmont 1:fdd22bb7aa52 131 /* Scale the input and then store the result in the destination buffer. */
emilmont 1:fdd22bb7aa52 132 *pDst++ = (q7_t) (__SSAT((((q15_t) * pSrc++ * scaleFract) >> kShift), 8));
emilmont 1:fdd22bb7aa52 133
emilmont 1:fdd22bb7aa52 134 /* Decrement the loop counter */
emilmont 1:fdd22bb7aa52 135 blkCnt--;
emilmont 1:fdd22bb7aa52 136 }
emilmont 1:fdd22bb7aa52 137
emilmont 1:fdd22bb7aa52 138 #endif /* #ifndef ARM_MATH_CM0 */
emilmont 1:fdd22bb7aa52 139
emilmont 1:fdd22bb7aa52 140 }
emilmont 1:fdd22bb7aa52 141
emilmont 1:fdd22bb7aa52 142 /**
emilmont 1:fdd22bb7aa52 143 * @} end of scale group
emilmont 1:fdd22bb7aa52 144 */