arm_scale_q7.c
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| text/x-c
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CLexer
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r41 | /* ---------------------------------------------------------------------- | ||
* Copyright (C) 2010 ARM Limited. All rights reserved. | ||||
* | ||||
* $Date: 15. July 2011 | ||||
* $Revision: V1.0.10 | ||||
* | ||||
* Project: CMSIS DSP Library | ||||
* Title: arm_scale_q7.c | ||||
* | ||||
* Description: Multiplies a Q7 vector by a scalar. | ||||
* | ||||
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 | ||||
* | ||||
* Version 1.0.10 2011/7/15 | ||||
* Big Endian support added and Merged M0 and M3/M4 Source code. | ||||
* | ||||
* Version 1.0.3 2010/11/29 | ||||
* Re-organized the CMSIS folders and updated documentation. | ||||
* | ||||
* Version 1.0.2 2010/11/11 | ||||
* Documentation updated. | ||||
* | ||||
* Version 1.0.1 2010/10/05 | ||||
* Production release and review comments incorporated. | ||||
* | ||||
* Version 1.0.0 2010/09/20 | ||||
* Production release and review comments incorporated | ||||
* | ||||
* Version 0.0.7 2010/06/10 | ||||
* Misra-C changes done | ||||
* -------------------------------------------------------------------- */ | ||||
#include "arm_math.h" | ||||
/** | ||||
* @ingroup groupMath | ||||
*/ | ||||
/** | ||||
* @addtogroup scale | ||||
* @{ | ||||
*/ | ||||
/** | ||||
* @brief Multiplies a Q7 vector by a scalar. | ||||
* @param[in] *pSrc points to the input vector | ||||
* @param[in] scaleFract fractional portion of the scale value | ||||
* @param[in] shift number of bits to shift the result by | ||||
* @param[out] *pDst points to the output vector | ||||
* @param[in] blockSize number of samples in the vector | ||||
* @return none. | ||||
* | ||||
* <b>Scaling and Overflow Behavior:</b> | ||||
* \par | ||||
* The input data <code>*pSrc</code> and <code>scaleFract</code> are in 1.7 format. | ||||
* These are multiplied to yield a 2.14 intermediate result and this is shifted with saturation to 1.7 format. | ||||
*/ | ||||
void arm_scale_q7( | ||||
q7_t * pSrc, | ||||
q7_t scaleFract, | ||||
int8_t shift, | ||||
q7_t * pDst, | ||||
uint32_t blockSize) | ||||
{ | ||||
int8_t kShift = 7 - shift; /* shift to apply after scaling */ | ||||
uint32_t blkCnt; /* loop counter */ | ||||
#ifndef ARM_MATH_CM0 | ||||
/* Run the below code for Cortex-M4 and Cortex-M3 */ | ||||
q7_t in1, in2, in3, in4, out1, out2, out3, out4; /* Temporary variables to store input & output */ | ||||
/*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) | ||||
{ | ||||
/* Reading 4 inputs from memory */ | ||||
in1 = *pSrc++; | ||||
in2 = *pSrc++; | ||||
in3 = *pSrc++; | ||||
in4 = *pSrc++; | ||||
/* C = A * scale */ | ||||
/* Scale the inputs and then store the results in the temporary variables. */ | ||||
out1 = (q7_t) (__SSAT(((in1) * scaleFract) >> kShift, 8)); | ||||
out2 = (q7_t) (__SSAT(((in2) * scaleFract) >> kShift, 8)); | ||||
out3 = (q7_t) (__SSAT(((in3) * scaleFract) >> kShift, 8)); | ||||
out4 = (q7_t) (__SSAT(((in4) * scaleFract) >> kShift, 8)); | ||||
/* Packing the individual outputs into 32bit and storing in | ||||
* destination buffer in single write */ | ||||
*__SIMD32(pDst)++ = __PACKq7(out1, out2, out3, out4); | ||||
/* 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 * scale */ | ||||
/* Scale the input and then store the result in the destination buffer. */ | ||||
*pDst++ = (q7_t) (__SSAT(((*pSrc++) * scaleFract) >> kShift, 8)); | ||||
/* Decrement the loop counter */ | ||||
blkCnt--; | ||||
} | ||||
#else | ||||
/* Run the below code for Cortex-M0 */ | ||||
/* Initialize blkCnt with number of samples */ | ||||
blkCnt = blockSize; | ||||
while(blkCnt > 0u) | ||||
{ | ||||
/* C = A * scale */ | ||||
/* Scale the input and then store the result in the destination buffer. */ | ||||
*pDst++ = (q7_t) (__SSAT((((q15_t) * pSrc++ * scaleFract) >> kShift), 8)); | ||||
/* Decrement the loop counter */ | ||||
blkCnt--; | ||||
} | ||||
#endif /* #ifndef ARM_MATH_CM0 */ | ||||
} | ||||
/** | ||||
* @} end of scale group | ||||
*/ | ||||