| /* ---------------------------------------------------------------------- |
| * Copyright (C) 2010 ARM Limited. All rights reserved. |
| * |
| * $Date: 15. July 2011 |
| * $Revision: V1.0.10 |
| * |
| * Project: CMSIS DSP Library |
| * Title: arm_power_q7.c |
| * |
| * Description: Sum of the squares of the elements of a Q7 vector. |
| * |
| * 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. |
| * -------------------------------------------------------------------- */ |
| |
| #include "arm_math.h" |
| |
| /** |
| * @ingroup groupStats |
| */ |
| |
| /** |
| * @addtogroup power |
| * @{ |
| */ |
| |
| /** |
| * @brief Sum of the squares of the elements of a Q7 vector. |
| * @param[in] *pSrc points to the input vector |
| * @param[in] blockSize length of the input vector |
| * @param[out] *pResult sum of the squares value returned here |
| * @return none. |
| * |
| * @details |
| * <b>Scaling and Overflow Behavior:</b> |
| * |
| * \par |
| * The function is implemented using a 32-bit internal accumulator. |
| * The input is represented in 1.7 format. |
| * Intermediate multiplication yields a 2.14 format, and this |
| * result is added without saturation to an accumulator in 18.14 format. |
| * With 17 guard bits in the accumulator, there is no risk of overflow, and the |
| * full precision of the intermediate multiplication is preserved. |
| * Finally, the return result is in 18.14 format. |
| * |
| */ |
| |
| void arm_power_q7( |
| q7_t * pSrc, |
| uint32_t blockSize, |
| q31_t * pResult) |
| { |
| q31_t sum = 0; /* Temporary result storage */ |
| q7_t in; /* Temporary variable to store input */ |
| uint32_t blkCnt; /* loop counter */ |
| |
| #ifndef ARM_MATH_CM0 |
| |
| /* Run the below code for Cortex-M4 and Cortex-M3 */ |
| |
| q31_t input1; /* Temporary variable to store packed input */ |
| q15_t in1, in2; /* Temporary variables to store input */ |
| |
| /*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 two inputs of pSrc vector and packing */ |
| in1 = (q15_t) * pSrc++; |
| in2 = (q15_t) * pSrc++; |
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */ |
| /* Compute Power and then store the result in a temporary variable, sum. */ |
| sum = __SMLAD(input1, input1, sum); |
| |
| /* Reading two inputs of pSrc vector and packing */ |
| in1 = (q15_t) * pSrc++; |
| in2 = (q15_t) * pSrc++; |
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */ |
| /* Compute Power and then store the result in a temporary variable, sum. */ |
| sum = __SMLAD(input1, input1, sum); |
| |
| /* 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 */ |
| |
| /* Loop over blockSize number of values */ |
| blkCnt = blockSize; |
| |
| #endif /* #ifndef ARM_MATH_CM0 */ |
| |
| while(blkCnt > 0u) |
| { |
| /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */ |
| /* Compute Power and then store the result in a temporary variable, sum. */ |
| in = *pSrc++; |
| sum += ((q15_t) in * in); |
| |
| /* Decrement the loop counter */ |
| blkCnt--; |
| } |
| |
| /* Store the result in 18.14 format */ |
| *pResult = sum; |
| } |
| |
| /** |
| * @} end of power group |
| */ |