| /* ---------------------------------------------------------------------- |
| * Project: CMSIS DSP Library |
| * Title: arm_mult_q15.c |
| * Description: Q15 vector multiplication |
| * |
| * $Date: 18. March 2019 |
| * $Revision: V1.6.0 |
| * |
| * Target Processor: Cortex-M cores |
| * -------------------------------------------------------------------- */ |
| /* |
| * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved. |
| * |
| * SPDX-License-Identifier: Apache-2.0 |
| * |
| * Licensed under the Apache License, Version 2.0 (the License); you may |
| * not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an AS IS BASIS, WITHOUT |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "arm_math.h" |
| |
| /** |
| @ingroup groupMath |
| */ |
| |
| /** |
| @addtogroup BasicMult |
| @{ |
| */ |
| |
| /** |
| @brief Q15 vector multiplication |
| @param[in] pSrcA points to first input vector |
| @param[in] pSrcB points to second input vector |
| @param[out] pDst points to output vector |
| @param[in] blockSize number of samples in each vector |
| @return none |
| |
| @par Scaling and Overflow Behavior |
| The function uses saturating arithmetic. |
| Results outside of the allowable Q15 range [0x8000 0x7FFF] are saturated. |
| */ |
| |
| void arm_mult_q15( |
| const q15_t * pSrcA, |
| const q15_t * pSrcB, |
| q15_t * pDst, |
| uint32_t blockSize) |
| { |
| uint32_t blkCnt; /* Loop counter */ |
| |
| #if defined (ARM_MATH_LOOPUNROLL) |
| |
| #if defined (ARM_MATH_DSP) |
| q31_t inA1, inA2, inB1, inB2; /* Temporary input variables */ |
| q15_t out1, out2, out3, out4; /* Temporary output variables */ |
| q31_t mul1, mul2, mul3, mul4; /* Temporary variables */ |
| #endif |
| |
| /* Loop unrolling: Compute 4 outputs at a time */ |
| blkCnt = blockSize >> 2U; |
| |
| while (blkCnt > 0U) |
| { |
| /* C = A * B */ |
| |
| #if defined (ARM_MATH_DSP) |
| /* read 2 samples at a time from sourceA */ |
| inA1 = read_q15x2_ia ((q15_t **) &pSrcA); |
| /* read 2 samples at a time from sourceB */ |
| inB1 = read_q15x2_ia ((q15_t **) &pSrcB); |
| /* read 2 samples at a time from sourceA */ |
| inA2 = read_q15x2_ia ((q15_t **) &pSrcA); |
| /* read 2 samples at a time from sourceB */ |
| inB2 = read_q15x2_ia ((q15_t **) &pSrcB); |
| |
| /* multiply mul = sourceA * sourceB */ |
| mul1 = (q31_t) ((q15_t) (inA1 >> 16) * (q15_t) (inB1 >> 16)); |
| mul2 = (q31_t) ((q15_t) (inA1 ) * (q15_t) (inB1 )); |
| mul3 = (q31_t) ((q15_t) (inA2 >> 16) * (q15_t) (inB2 >> 16)); |
| mul4 = (q31_t) ((q15_t) (inA2 ) * (q15_t) (inB2 )); |
| |
| /* saturate result to 16 bit */ |
| out1 = (q15_t) __SSAT(mul1 >> 15, 16); |
| out2 = (q15_t) __SSAT(mul2 >> 15, 16); |
| out3 = (q15_t) __SSAT(mul3 >> 15, 16); |
| out4 = (q15_t) __SSAT(mul4 >> 15, 16); |
| |
| /* store result to destination */ |
| #ifndef ARM_MATH_BIG_ENDIAN |
| write_q15x2_ia (&pDst, __PKHBT(out2, out1, 16)); |
| write_q15x2_ia (&pDst, __PKHBT(out4, out3, 16)); |
| #else |
| write_q15x2_ia (&pDst, __PKHBT(out1, out2, 16)); |
| write_q15x2_ia (&pDst, __PKHBT(out3, out4, 16)); |
| #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
| |
| #else |
| *pDst++ = (q15_t) __SSAT((((q31_t) (*pSrcA++) * (*pSrcB++)) >> 15), 16); |
| *pDst++ = (q15_t) __SSAT((((q31_t) (*pSrcA++) * (*pSrcB++)) >> 15), 16); |
| *pDst++ = (q15_t) __SSAT((((q31_t) (*pSrcA++) * (*pSrcB++)) >> 15), 16); |
| *pDst++ = (q15_t) __SSAT((((q31_t) (*pSrcA++) * (*pSrcB++)) >> 15), 16); |
| #endif |
| |
| /* Decrement loop counter */ |
| blkCnt--; |
| } |
| |
| /* Loop unrolling: Compute remaining outputs */ |
| blkCnt = blockSize % 0x4U; |
| |
| #else |
| |
| /* Initialize blkCnt with number of samples */ |
| blkCnt = blockSize; |
| |
| #endif /* #if defined (ARM_MATH_LOOPUNROLL) */ |
| |
| while (blkCnt > 0U) |
| { |
| /* C = A * B */ |
| |
| /* Multiply inputs and store result in destination buffer. */ |
| *pDst++ = (q15_t) __SSAT((((q31_t) (*pSrcA++) * (*pSrcB++)) >> 15), 16); |
| |
| /* Decrement loop counter */ |
| blkCnt--; |
| } |
| |
| } |
| |
| /** |
| @} end of BasicMult group |
| */ |