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Diffstat (limited to 'DSP_Lib/Source/BasicMathFunctions/arm_shift_q7.c')
-rw-r--r-- | DSP_Lib/Source/BasicMathFunctions/arm_shift_q7.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/DSP_Lib/Source/BasicMathFunctions/arm_shift_q7.c b/DSP_Lib/Source/BasicMathFunctions/arm_shift_q7.c new file mode 100644 index 0000000..f925054 --- /dev/null +++ b/DSP_Lib/Source/BasicMathFunctions/arm_shift_q7.c @@ -0,0 +1,220 @@ +/* ---------------------------------------------------------------------- +* Copyright (C) 2010-2014 ARM Limited. All rights reserved. +* +* $Date: 19. March 2015 +* $Revision: V.1.4.5 +* +* Project: CMSIS DSP Library +* Title: arm_shift_q7.c +* +* Description: Processing function for the Q7 Shifting +* +* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 +* +* Redistribution and use in source and binary forms, with or without +* modification, are permitted provided that the following conditions +* are met: +* - Redistributions of source code must retain the above copyright +* notice, this list of conditions and the following disclaimer. +* - Redistributions in binary form must reproduce the above copyright +* notice, this list of conditions and the following disclaimer in +* the documentation and/or other materials provided with the +* distribution. +* - Neither the name of ARM LIMITED nor the names of its contributors +* may be used to endorse or promote products derived from this +* software without specific prior written permission. +* +* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS +* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE +* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, +* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, +* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN +* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +* POSSIBILITY OF SUCH DAMAGE. +* -------------------------------------------------------------------- */ + +#include "arm_math.h" + +/** + * @ingroup groupMath + */ + +/** + * @addtogroup shift + * @{ + */ + + +/** + * @brief Shifts the elements of a Q7 vector a specified number of bits. + * @param[in] *pSrc points to the input vector + * @param[in] shiftBits number of bits to shift. A positive value shifts left; a negative value shifts right. + * @param[out] *pDst points to the output vector + * @param[in] blockSize number of samples in the vector + * @return none. + * + * \par Conditions for optimum performance + * Input and output buffers should be aligned by 32-bit + * + * + * <b>Scaling and Overflow Behavior:</b> + * \par + * The function uses saturating arithmetic. + * Results outside of the allowable Q7 range [0x8 0x7F] will be saturated. + */ + +void arm_shift_q7( + q7_t * pSrc, + int8_t shiftBits, + q7_t * pDst, + uint32_t blockSize) +{ + uint32_t blkCnt; /* loop counter */ + uint8_t sign; /* Sign of shiftBits */ + +#ifndef ARM_MATH_CM0_FAMILY + +/* Run the below code for Cortex-M4 and Cortex-M3 */ + q7_t in1; /* Input value1 */ + q7_t in2; /* Input value2 */ + q7_t in3; /* Input value3 */ + q7_t in4; /* Input value4 */ + + + /*loop Unrolling */ + blkCnt = blockSize >> 2u; + + /* Getting the sign of shiftBits */ + sign = (shiftBits & 0x80); + + /* If the shift value is positive then do right shift else left shift */ + if(sign == 0u) + { + /* First part of the processing with loop unrolling. Compute 4 outputs at a time. + ** a second loop below computes the remaining 1 to 3 samples. */ + while(blkCnt > 0u) + { + /* C = A << shiftBits */ + /* Read 4 inputs */ + in1 = *pSrc; + in2 = *(pSrc + 1); + in3 = *(pSrc + 2); + in4 = *(pSrc + 3); + + /* Store the Shifted result in the destination buffer in single cycle by packing the outputs */ + *__SIMD32(pDst)++ = __PACKq7(__SSAT((in1 << shiftBits), 8), + __SSAT((in2 << shiftBits), 8), + __SSAT((in3 << shiftBits), 8), + __SSAT((in4 << shiftBits), 8)); + /* Update source pointer to process next sampels */ + pSrc += 4u; + + /* Decrement the loop counter */ + blkCnt--; + } + + /* If the blockSize is not a multiple of 4, compute any remaining output samples here. + ** No loop unrolling is used. */ + blkCnt = blockSize % 0x4u; + + while(blkCnt > 0u) + { + /* C = A << shiftBits */ + /* Shift the input and then store the result in the destination buffer. */ + *pDst++ = (q7_t) __SSAT((*pSrc++ << shiftBits), 8); + + /* Decrement the loop counter */ + blkCnt--; + } + } + else + { + shiftBits = -shiftBits; + /* First part of the processing with loop unrolling. Compute 4 outputs at a time. + ** a second loop below computes the remaining 1 to 3 samples. */ + while(blkCnt > 0u) + { + /* C = A >> shiftBits */ + /* Read 4 inputs */ + in1 = *pSrc; + in2 = *(pSrc + 1); + in3 = *(pSrc + 2); + in4 = *(pSrc + 3); + + /* Store the Shifted result in the destination buffer in single cycle by packing the outputs */ + *__SIMD32(pDst)++ = __PACKq7((in1 >> shiftBits), (in2 >> shiftBits), + (in3 >> shiftBits), (in4 >> shiftBits)); + + + pSrc += 4u; + + /* Decrement the loop counter */ + blkCnt--; + } + + /* If the blockSize is not a multiple of 4, compute any remaining output samples here. + ** No loop unrolling is used. */ + blkCnt = blockSize % 0x4u; + + while(blkCnt > 0u) + { + /* C = A >> shiftBits */ + /* Shift the input and then store the result in the destination buffer. */ + in1 = *pSrc++; + *pDst++ = (in1 >> shiftBits); + + /* Decrement the loop counter */ + blkCnt--; + } + } + +#else + + /* Run the below code for Cortex-M0 */ + + /* Getting the sign of shiftBits */ + sign = (shiftBits & 0x80); + + /* If the shift value is positive then do right shift else left shift */ + if(sign == 0u) + { + /* Initialize blkCnt with number of samples */ + blkCnt = blockSize; + + while(blkCnt > 0u) + { + /* C = A << shiftBits */ + /* Shift the input and then store the result in the destination buffer. */ + *pDst++ = (q7_t) __SSAT(((q15_t) * pSrc++ << shiftBits), 8); + + /* Decrement the loop counter */ + blkCnt--; + } + } + else + { + /* Initialize blkCnt with number of samples */ + blkCnt = blockSize; + + while(blkCnt > 0u) + { + /* C = A >> shiftBits */ + /* Shift the input and then store the result in the destination buffer. */ + *pDst++ = (*pSrc++ >> -shiftBits); + + /* Decrement the loop counter */ + blkCnt--; + } + } + +#endif /* #ifndef ARM_MATH_CM0_FAMILY */ +} + +/** + * @} end of shift group + */ |