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_shift_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_shift_q7.c |
simon | 0:1014af42efd9 | 9 | * |
simon | 0:1014af42efd9 | 10 | * Description: Processing function for the Q7 Shifting |
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 shift |
simon | 0:1014af42efd9 | 38 | * @{ |
simon | 0:1014af42efd9 | 39 | */ |
simon | 0:1014af42efd9 | 40 | |
simon | 0:1014af42efd9 | 41 | |
simon | 0:1014af42efd9 | 42 | /** |
simon | 0:1014af42efd9 | 43 | * @brief Shifts the elements of a Q7 vector a specified number of bits. |
simon | 0:1014af42efd9 | 44 | * @param *pSrc points to the input vector |
simon | 0:1014af42efd9 | 45 | * @param shiftBits number of bits to shift. A positive value shifts left; a negative value shifts right. |
simon | 0:1014af42efd9 | 46 | * @param *pDst points to the output vector |
simon | 0:1014af42efd9 | 47 | * @param blockSize number of samples in the vector |
simon | 0:1014af42efd9 | 48 | * @return none. |
simon | 0:1014af42efd9 | 49 | * |
simon | 0:1014af42efd9 | 50 | * <b>Scaling and Overflow Behavior:</b> |
simon | 0:1014af42efd9 | 51 | * \par |
simon | 0:1014af42efd9 | 52 | * The function uses saturating arithmetic. |
simon | 0:1014af42efd9 | 53 | * Results outside of the allowable Q7 range [0x8 0x7F] will be saturated. |
simon | 0:1014af42efd9 | 54 | */ |
simon | 0:1014af42efd9 | 55 | |
simon | 0:1014af42efd9 | 56 | void arm_shift_q7( |
simon | 0:1014af42efd9 | 57 | q7_t * pSrc, |
simon | 0:1014af42efd9 | 58 | int8_t shiftBits, |
simon | 0:1014af42efd9 | 59 | q7_t * pDst, |
simon | 0:1014af42efd9 | 60 | uint32_t blockSize) |
simon | 0:1014af42efd9 | 61 | { |
simon | 0:1014af42efd9 | 62 | uint32_t blkCnt; /* loop counter */ |
simon | 0:1014af42efd9 | 63 | uint8_t sign; /* Sign of shiftBits */ |
simon | 0:1014af42efd9 | 64 | q7_t in1; /* Input value1 */ |
simon | 0:1014af42efd9 | 65 | q7_t in2; /* Input value2 */ |
simon | 0:1014af42efd9 | 66 | q7_t in3; /* Input value3 */ |
simon | 0:1014af42efd9 | 67 | q7_t in4; /* Input value4 */ |
simon | 0:1014af42efd9 | 68 | |
simon | 0:1014af42efd9 | 69 | |
simon | 0:1014af42efd9 | 70 | /*loop Unrolling */ |
simon | 0:1014af42efd9 | 71 | blkCnt = blockSize >> 2u; |
simon | 0:1014af42efd9 | 72 | |
simon | 0:1014af42efd9 | 73 | /* Getting the sign of shiftBits */ |
simon | 0:1014af42efd9 | 74 | sign = (shiftBits & 0x80); |
simon | 0:1014af42efd9 | 75 | |
simon | 0:1014af42efd9 | 76 | /* If the shift value is positive then do right shift else left shift */ |
simon | 0:1014af42efd9 | 77 | if(sign == 0u) |
simon | 0:1014af42efd9 | 78 | { |
simon | 0:1014af42efd9 | 79 | /* First part of the processing with loop unrolling. Compute 4 outputs at a time. |
simon | 0:1014af42efd9 | 80 | ** a second loop below computes the remaining 1 to 3 samples. */ |
simon | 0:1014af42efd9 | 81 | while(blkCnt > 0u) |
simon | 0:1014af42efd9 | 82 | { |
simon | 0:1014af42efd9 | 83 | /* C = A << shiftBits */ |
simon | 0:1014af42efd9 | 84 | /* Read 4 inputs */ |
simon | 0:1014af42efd9 | 85 | in1 = *pSrc++; |
simon | 0:1014af42efd9 | 86 | in2 = *pSrc++; |
simon | 0:1014af42efd9 | 87 | in3 = *pSrc++; |
simon | 0:1014af42efd9 | 88 | in4 = *pSrc++; |
simon | 0:1014af42efd9 | 89 | |
simon | 0:1014af42efd9 | 90 | /* Store the Shifted result in the destination buffer in single cycle by packing the outputs */ |
simon | 0:1014af42efd9 | 91 | *__SIMD32(pDst)++ = __PACKq7(__SSAT((in1 << shiftBits), 8), |
simon | 0:1014af42efd9 | 92 | __SSAT((in2 << shiftBits), 8), |
simon | 0:1014af42efd9 | 93 | __SSAT((in3 << shiftBits), 8), |
simon | 0:1014af42efd9 | 94 | __SSAT((in4 << shiftBits), 8)); |
simon | 0:1014af42efd9 | 95 | |
simon | 0:1014af42efd9 | 96 | /* Decrement the loop counter */ |
simon | 0:1014af42efd9 | 97 | blkCnt--; |
simon | 0:1014af42efd9 | 98 | } |
simon | 0:1014af42efd9 | 99 | |
simon | 0:1014af42efd9 | 100 | /* If the blockSize is not a multiple of 4, compute any remaining output samples here. |
simon | 0:1014af42efd9 | 101 | ** No loop unrolling is used. */ |
simon | 0:1014af42efd9 | 102 | blkCnt = blockSize % 0x4u; |
simon | 0:1014af42efd9 | 103 | |
simon | 0:1014af42efd9 | 104 | while(blkCnt > 0u) |
simon | 0:1014af42efd9 | 105 | { |
simon | 0:1014af42efd9 | 106 | /* C = A << shiftBits */ |
simon | 0:1014af42efd9 | 107 | /* Shift the input and then store the result in the destination buffer. */ |
simon | 0:1014af42efd9 | 108 | *pDst++ = (q7_t) __SSAT((*pSrc++ << shiftBits), 8); |
simon | 0:1014af42efd9 | 109 | |
simon | 0:1014af42efd9 | 110 | /* Decrement the loop counter */ |
simon | 0:1014af42efd9 | 111 | blkCnt--; |
simon | 0:1014af42efd9 | 112 | } |
simon | 0:1014af42efd9 | 113 | } |
simon | 0:1014af42efd9 | 114 | else |
simon | 0:1014af42efd9 | 115 | { |
simon | 0:1014af42efd9 | 116 | /* First part of the processing with loop unrolling. Compute 4 outputs at a time. |
simon | 0:1014af42efd9 | 117 | ** a second loop below computes the remaining 1 to 3 samples. */ |
simon | 0:1014af42efd9 | 118 | while(blkCnt > 0u) |
simon | 0:1014af42efd9 | 119 | { |
simon | 0:1014af42efd9 | 120 | /* C = A >> shiftBits */ |
simon | 0:1014af42efd9 | 121 | /* Read 4 inputs */ |
simon | 0:1014af42efd9 | 122 | in1 = *pSrc++; |
simon | 0:1014af42efd9 | 123 | in2 = *pSrc++; |
simon | 0:1014af42efd9 | 124 | in3 = *pSrc++; |
simon | 0:1014af42efd9 | 125 | in4 = *pSrc++; |
simon | 0:1014af42efd9 | 126 | |
simon | 0:1014af42efd9 | 127 | /* Store the Shifted result in the destination buffer in single cycle by packing the outputs */ |
simon | 0:1014af42efd9 | 128 | *__SIMD32(pDst)++ = __PACKq7((in1 >> -shiftBits), (in2 >> -shiftBits), |
simon | 0:1014af42efd9 | 129 | (in3 >> -shiftBits), (in4 >> -shiftBits)); |
simon | 0:1014af42efd9 | 130 | |
simon | 0:1014af42efd9 | 131 | /* Decrement the loop counter */ |
simon | 0:1014af42efd9 | 132 | blkCnt--; |
simon | 0:1014af42efd9 | 133 | } |
simon | 0:1014af42efd9 | 134 | |
simon | 0:1014af42efd9 | 135 | /* If the blockSize is not a multiple of 4, compute any remaining output samples here. |
simon | 0:1014af42efd9 | 136 | ** No loop unrolling is used. */ |
simon | 0:1014af42efd9 | 137 | blkCnt = blockSize % 0x4u; |
simon | 0:1014af42efd9 | 138 | |
simon | 0:1014af42efd9 | 139 | while(blkCnt > 0u) |
simon | 0:1014af42efd9 | 140 | { |
simon | 0:1014af42efd9 | 141 | /* C = A >> shiftBits */ |
simon | 0:1014af42efd9 | 142 | /* Shift the input and then store the result in the destination buffer. */ |
simon | 0:1014af42efd9 | 143 | *pDst++ = (*pSrc++ >> -shiftBits); |
simon | 0:1014af42efd9 | 144 | |
simon | 0:1014af42efd9 | 145 | /* Decrement the loop counter */ |
simon | 0:1014af42efd9 | 146 | blkCnt--; |
simon | 0:1014af42efd9 | 147 | } |
simon | 0:1014af42efd9 | 148 | } |
simon | 0:1014af42efd9 | 149 | } |
simon | 0:1014af42efd9 | 150 | |
simon | 0:1014af42efd9 | 151 | /** |
simon | 0:1014af42efd9 | 152 | * @} end of shift group |
simon | 0:1014af42efd9 | 153 | */ |