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Diffstat (limited to 'DSP_Lib/Source/BasicMathFunctions/arm_abs_q7.c')
-rw-r--r-- | DSP_Lib/Source/BasicMathFunctions/arm_abs_q7.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/DSP_Lib/Source/BasicMathFunctions/arm_abs_q7.c b/DSP_Lib/Source/BasicMathFunctions/arm_abs_q7.c new file mode 100644 index 0000000..54c6f71 --- /dev/null +++ b/DSP_Lib/Source/BasicMathFunctions/arm_abs_q7.c @@ -0,0 +1,157 @@ +/* ---------------------------------------------------------------------- +* Copyright (C) 2010-2014 ARM Limited. All rights reserved. +* +* $Date: 19. March 2015 +* $Revision: V.1.4.5 +* +* Project: CMSIS DSP Library +* Title: arm_abs_q7.c +* +* Description: Q7 vector absolute value. +* +* 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 BasicAbs + * @{ + */ + +/** + * @brief Q7 vector absolute value. + * @param[in] *pSrc points to the input buffer + * @param[out] *pDst points to the output buffer + * @param[in] blockSize number of samples in each 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. + * The Q7 value -1 (0x80) will be saturated to the maximum allowable positive value 0x7F. + */ + +void arm_abs_q7( + q7_t * pSrc, + q7_t * pDst, + uint32_t blockSize) +{ + uint32_t blkCnt; /* loop counter */ + q7_t in; /* Input value1 */ + +#ifndef ARM_MATH_CM0_FAMILY + + /* Run the below code for Cortex-M4 and Cortex-M3 */ + q31_t in1, in2, in3, in4; /* temporary input variables */ + q31_t out1, out2, out3, out4; /* temporary output variables */ + + /*loop Unrolling */ + blkCnt = blockSize >> 2u; + + /* 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| */ + /* Read inputs */ + in1 = (q31_t) * pSrc; + in2 = (q31_t) * (pSrc + 1); + in3 = (q31_t) * (pSrc + 2); + + /* find absolute value */ + out1 = (in1 > 0) ? in1 : (q31_t)__QSUB8(0, in1); + + /* read input */ + in4 = (q31_t) * (pSrc + 3); + + /* find absolute value */ + out2 = (in2 > 0) ? in2 : (q31_t)__QSUB8(0, in2); + + /* store result to destination */ + *pDst = (q7_t) out1; + + /* find absolute value */ + out3 = (in3 > 0) ? in3 : (q31_t)__QSUB8(0, in3); + + /* find absolute value */ + out4 = (in4 > 0) ? in4 : (q31_t)__QSUB8(0, in4); + + /* store result to destination */ + *(pDst + 1) = (q7_t) out2; + + /* store result to destination */ + *(pDst + 2) = (q7_t) out3; + + /* store result to destination */ + *(pDst + 3) = (q7_t) out4; + + /* update pointers to process next samples */ + pSrc += 4u; + pDst += 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; +#else + + /* Run the below code for Cortex-M0 */ + blkCnt = blockSize; + +#endif /* #define ARM_MATH_CM0_FAMILY */ + + while(blkCnt > 0u) + { + /* C = |A| */ + /* Read the input */ + in = *pSrc++; + + /* Store the Absolute result in the destination buffer */ + *pDst++ = (in > 0) ? in : ((in == (q7_t) 0x80) ? 0x7f : -in); + + /* Decrement the loop counter */ + blkCnt--; + } +} + +/** + * @} end of BasicAbs group + */ |