mbed-os 6.10 versione
cmsis_dsp/BasicMathFunctions/arm_scale_q7.c
- Committer:
- emilmont
- Date:
- 2013-05-30
- Revision:
- 2:da51fb522205
- Parent:
- 1:fdd22bb7aa52
- Child:
- 3:7a284390b0ce
File content as of revision 2:da51fb522205:
/* ---------------------------------------------------------------------- * Copyright (C) 2010 ARM Limited. All rights reserved. * * $Date: 15. February 2012 * $Revision: V1.1.0 * * 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 1.1.0 2012/02/15 * Updated with more optimizations, bug fixes and minor API changes. * * 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 */