| /* ---------------------------------------------------------------------- |
| * Copyright (C) 2010 ARM Limited. All rights reserved. |
| * |
| * $Date: 15. July 2011 |
| * $Revision: V1.0.10 |
| * |
| * Project: CMSIS DSP Library |
| * Title: arm_negate_q7.c |
| * |
| * Description: Negates Q7 vectors. |
| * |
| * 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 negate |
| * @{ |
| */ |
| |
| /** |
| * @brief Negates the elements of a Q7 vector. |
| * @param[in] *pSrc points to the input vector |
| * @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 function uses saturating arithmetic. |
| * The Q7 value -1 (0x80) will be saturated to the maximum allowable positive value 0x7F. |
| */ |
| |
| void arm_negate_q7( |
| q7_t * pSrc, |
| q7_t * pDst, |
| uint32_t blockSize) |
| { |
| uint32_t blkCnt; /* loop counter */ |
| |
| #ifndef ARM_MATH_CM0 |
| |
| /* 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; |
| |
| /* 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 four inputs */ |
| in1 = *pSrc++; |
| in2 = *pSrc++; |
| in3 = *pSrc++; |
| in4 = *pSrc++; |
| |
| /* Store the Negated results in the destination buffer in a single cycle by packing the results */ |
| *__SIMD32(pDst)++ = |
| __PACKq7(__SSAT(-in1, 8), __SSAT(-in2, 8), __SSAT(-in3, 8), |
| __SSAT(-in4, 8)); |
| |
| /* 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 */ |
| |
| /* Initialize blkCnt with number of samples */ |
| blkCnt = blockSize; |
| |
| #endif /* #ifndef ARM_MATH_CM0 */ |
| |
| while(blkCnt > 0u) |
| { |
| /* C = -A */ |
| /* Negate and then store the results in the destination buffer. */ |
| *pDst++ = __SSAT(-*pSrc++, 8); |
| |
| /* Decrement the loop counter */ |
| blkCnt--; |
| } |
| } |
| |
| /** |
| * @} end of negate group |
| */ |
