Simon Ford
CMSIS DSP Library from CMSIS 2.0. See http://www.onarm.com/cmsis/ for full details
Dependents: K22F_DSP_Matrix_least_square BNO055-ELEC3810 1BNO055 ECE4180Project--Slave2 ... more
src/Cortex-M4-M3/BasicMathFunctions/arm_sub_q7.c@0:1014af42efd9, 2011-03-10 (annotated)
- Committer:
- simon
- Date:
- Thu Mar 10 15:07:50 2011 +0000
- Revision:
- 0:1014af42efd9
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| simon | 0:1014af42efd9 | 1 | /* ---------------------------------------------------------------------- |
| simon | 0:1014af42efd9 | 2 | * Copyright (C) 2010 ARM Limited. All rights reserved. |
| simon | 0:1014af42efd9 | 3 | * |
| simon | 0:1014af42efd9 | 4 | * $Date: 29. November 2010 |
| simon | 0:1014af42efd9 | 5 | * $Revision: V1.0.3 |
| simon | 0:1014af42efd9 | 6 | * |
| simon | 0:1014af42efd9 | 7 | * Project: CMSIS DSP Library |
| simon | 0:1014af42efd9 | 8 | * Title: arm_sub_q7.c |
| simon | 0:1014af42efd9 | 9 | * |
| simon | 0:1014af42efd9 | 10 | * Description: Q7 vector subtraction. |
| simon | 0:1014af42efd9 | 11 | * |
| simon | 0:1014af42efd9 | 12 | * Target Processor: Cortex-M4/Cortex-M3 |
| simon | 0:1014af42efd9 | 13 | * |
| simon | 0:1014af42efd9 | 14 | * Version 1.0.3 2010/11/29 |
| simon | 0:1014af42efd9 | 15 | * Re-organized the CMSIS folders and updated documentation. |
| simon | 0:1014af42efd9 | 16 | * |
| simon | 0:1014af42efd9 | 17 | * Version 1.0.2 2010/11/11 |
| simon | 0:1014af42efd9 | 18 | * Documentation updated. |
| simon | 0:1014af42efd9 | 19 | * |
| simon | 0:1014af42efd9 | 20 | * Version 1.0.1 2010/10/05 |
| simon | 0:1014af42efd9 | 21 | * Production release and review comments incorporated. |
| simon | 0:1014af42efd9 | 22 | * |
| simon | 0:1014af42efd9 | 23 | * Version 1.0.0 2010/09/20 |
| simon | 0:1014af42efd9 | 24 | * Production release and review comments incorporated. |
| simon | 0:1014af42efd9 | 25 | * |
| simon | 0:1014af42efd9 | 26 | * Version 0.0.7 2010/06/10 |
| simon | 0:1014af42efd9 | 27 | * Misra-C changes done |
| simon | 0:1014af42efd9 | 28 | * -------------------------------------------------------------------- */ |
| simon | 0:1014af42efd9 | 29 | |
| simon | 0:1014af42efd9 | 30 | #include "arm_math.h" |
| simon | 0:1014af42efd9 | 31 | |
| simon | 0:1014af42efd9 | 32 | /** |
| simon | 0:1014af42efd9 | 33 | * @ingroup groupMath |
| simon | 0:1014af42efd9 | 34 | */ |
| simon | 0:1014af42efd9 | 35 | |
| simon | 0:1014af42efd9 | 36 | /** |
| simon | 0:1014af42efd9 | 37 | * @addtogroup BasicSub |
| simon | 0:1014af42efd9 | 38 | * @{ |
| simon | 0:1014af42efd9 | 39 | */ |
| simon | 0:1014af42efd9 | 40 | |
| simon | 0:1014af42efd9 | 41 | /** |
| simon | 0:1014af42efd9 | 42 | * @brief Q7 vector subtraction. |
| simon | 0:1014af42efd9 | 43 | * @param[in] *pSrcA points to the first input vector |
| simon | 0:1014af42efd9 | 44 | * @param[in] *pSrcB points to the second input vector |
| simon | 0:1014af42efd9 | 45 | * @param[out] *pDst points to the output vector |
| simon | 0:1014af42efd9 | 46 | * @param[in] blockSize number of samples in each vector |
| simon | 0:1014af42efd9 | 47 | * @return none. |
| simon | 0:1014af42efd9 | 48 | * |
| simon | 0:1014af42efd9 | 49 | * <b>Scaling and Overflow Behavior:</b> |
| simon | 0:1014af42efd9 | 50 | * \par |
| simon | 0:1014af42efd9 | 51 | * The function uses saturating arithmetic. |
| simon | 0:1014af42efd9 | 52 | * Results outside of the allowable Q7 range [0x80 0x7F] will be saturated. |
| simon | 0:1014af42efd9 | 53 | */ |
| simon | 0:1014af42efd9 | 54 | |
| simon | 0:1014af42efd9 | 55 | void arm_sub_q7( |
| simon | 0:1014af42efd9 | 56 | q7_t * pSrcA, |
| simon | 0:1014af42efd9 | 57 | q7_t * pSrcB, |
| simon | 0:1014af42efd9 | 58 | q7_t * pDst, |
| simon | 0:1014af42efd9 | 59 | uint32_t blockSize) |
| simon | 0:1014af42efd9 | 60 | { |
| simon | 0:1014af42efd9 | 61 | uint32_t blkCnt; /* loop counter */ |
| simon | 0:1014af42efd9 | 62 | |
| simon | 0:1014af42efd9 | 63 | |
| simon | 0:1014af42efd9 | 64 | /*loop Unrolling */ |
| simon | 0:1014af42efd9 | 65 | blkCnt = blockSize >> 2u; |
| simon | 0:1014af42efd9 | 66 | |
| simon | 0:1014af42efd9 | 67 | /* First part of the processing with loop unrolling. Compute 4 outputs at a time. |
| simon | 0:1014af42efd9 | 68 | ** a second loop below computes the remaining 1 to 3 samples. */ |
| simon | 0:1014af42efd9 | 69 | while(blkCnt > 0u) |
| simon | 0:1014af42efd9 | 70 | { |
| simon | 0:1014af42efd9 | 71 | /* C = A - B */ |
| simon | 0:1014af42efd9 | 72 | /* Subtract and then store the results in the destination buffer 4 samples at a time. */ |
| simon | 0:1014af42efd9 | 73 | *__SIMD32(pDst)++ = __QSUB8(*__SIMD32(pSrcA)++, *__SIMD32(pSrcB)++); |
| simon | 0:1014af42efd9 | 74 | |
| simon | 0:1014af42efd9 | 75 | /* Decrement the loop counter */ |
| simon | 0:1014af42efd9 | 76 | blkCnt--; |
| simon | 0:1014af42efd9 | 77 | } |
| simon | 0:1014af42efd9 | 78 | |
| simon | 0:1014af42efd9 | 79 | /* If the blockSize is not a multiple of 4, compute any remaining output samples here. |
| simon | 0:1014af42efd9 | 80 | ** No loop unrolling is used. */ |
| simon | 0:1014af42efd9 | 81 | blkCnt = blockSize % 0x4u; |
| simon | 0:1014af42efd9 | 82 | |
| simon | 0:1014af42efd9 | 83 | while(blkCnt > 0u) |
| simon | 0:1014af42efd9 | 84 | { |
| simon | 0:1014af42efd9 | 85 | /* C = A - B */ |
| simon | 0:1014af42efd9 | 86 | /* Subtract and then store the result in the destination buffer. */ |
| simon | 0:1014af42efd9 | 87 | *pDst++ = __SSAT(*pSrcA++ - *pSrcB++, 8); |
| simon | 0:1014af42efd9 | 88 | |
| simon | 0:1014af42efd9 | 89 | /* Decrement the loop counter */ |
| simon | 0:1014af42efd9 | 90 | blkCnt--; |
| simon | 0:1014af42efd9 | 91 | } |
| simon | 0:1014af42efd9 | 92 | |
| simon | 0:1014af42efd9 | 93 | } |
| simon | 0:1014af42efd9 | 94 | |
| simon | 0:1014af42efd9 | 95 | /** |
| simon | 0:1014af42efd9 | 96 | * @} end of BasicSub group |
| simon | 0:1014af42efd9 | 97 | */ |