/* ---------------------------------------------------------------------- * Project: CMSIS DSP Library * Title: arm_shift_q15.c * Description: Shifts the elements of a Q15 vector by a specified number of bits * * $Date: 23 April 2021 * $Revision: V1.9.0 * * Target Processor: Cortex-M and Cortex-A cores * -------------------------------------------------------------------- */ /* * Copyright (C) 2010-2021 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 "dsp/basic_math_functions.h" /** @ingroup groupMath */ /** @addtogroup BasicShift @{ */ /** @brief Shifts the elements of a Q15 vector a specified number of bits @param[in] pSrc points to the input vector @param[in] shiftBits number of bits to shift. A positive value shifts left; a negative value shifts right. @param[out] pDst points to the 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. */ #if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE) #include "arm_helium_utils.h" void arm_shift_q15( const q15_t * pSrc, int8_t shiftBits, q15_t * pDst, uint32_t blockSize) { uint32_t blkCnt; /* loop counters */ q15x8_t vecSrc; q15x8_t vecDst; /* Compute 8 outputs at a time */ blkCnt = blockSize >> 3; while (blkCnt > 0U) { /* * C = A (>> or <<) shiftBits * Shift the input and then store the result in the destination buffer. */ vecSrc = vld1q(pSrc); vecDst = vqshlq_r(vecSrc, shiftBits); vst1q(pDst, vecDst); /* * Decrement the blockSize loop counter */ blkCnt--; /* * advance vector source and destination pointers */ pSrc += 8; pDst += 8; } /* * tail */ blkCnt = blockSize & 7; if (blkCnt > 0U) { mve_pred16_t p0 = vctp16q(blkCnt); vecSrc = vld1q(pSrc); vecDst = vqshlq_r(vecSrc, shiftBits); vstrhq_p(pDst, vecDst, p0); } } #else void arm_shift_q15( const q15_t * pSrc, int8_t shiftBits, q15_t * pDst, uint32_t blockSize) { uint32_t blkCnt; /* Loop counter */ uint8_t sign = (shiftBits & 0x80); /* Sign of shiftBits */ #if defined (ARM_MATH_LOOPUNROLL) #if defined (ARM_MATH_DSP) q15_t in1, in2; /* Temporary input variables */ #endif /* Loop unrolling: Compute 4 outputs at a time */ blkCnt = blockSize >> 2U; /* If the shift value is positive then do right shift else left shift */ if (sign == 0U) { while (blkCnt > 0U) { /* C = A << shiftBits */ #if defined (ARM_MATH_DSP) /* read 2 samples from source */ in1 = *pSrc++; in2 = *pSrc++; /* Shift the inputs and then store the results in the destination buffer. */ #ifndef ARM_MATH_BIG_ENDIAN write_q15x2_ia (&pDst, __PKHBT(__SSAT(((q31_t) in1 << shiftBits), 16), __SSAT(((q31_t) in2 << shiftBits), 16), 16)); #else write_q15x2_ia (&pDst, __PKHBT(__SSAT(((q31_t) in2 << shiftBits), 16), __SSAT(((q31_t) in1 << shiftBits), 16), 16)); #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ /* read 2 samples from source */ in1 = *pSrc++; in2 = *pSrc++; #ifndef ARM_MATH_BIG_ENDIAN write_q15x2_ia (&pDst, __PKHBT(__SSAT(((q31_t) in1 << shiftBits), 16), __SSAT(((q31_t) in2 << shiftBits), 16), 16)); #else write_q15x2_ia (&pDst, __PKHBT(__SSAT(((q31_t) in2 << shiftBits), 16), __SSAT(((q31_t) in1 << shiftBits), 16), 16)); #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ #else *pDst++ = __SSAT(((q31_t) *pSrc++ << shiftBits), 16); *pDst++ = __SSAT(((q31_t) *pSrc++ << shiftBits), 16); *pDst++ = __SSAT(((q31_t) *pSrc++ << shiftBits), 16); *pDst++ = __SSAT(((q31_t) *pSrc++ << shiftBits), 16); #endif /* Decrement loop counter */ blkCnt--; } } else { while (blkCnt > 0U) { /* C = A >> shiftBits */ #if defined (ARM_MATH_DSP) /* read 2 samples from source */ in1 = *pSrc++; in2 = *pSrc++; /* Shift the inputs and then store the results in the destination buffer. */ #ifndef ARM_MATH_BIG_ENDIAN write_q15x2_ia (&pDst, __PKHBT((in1 >> -shiftBits), (in2 >> -shiftBits), 16)); #else write_q15x2_ia (&pDst, __PKHBT((in2 >> -shiftBits), (in1 >> -shiftBits), 16)); #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ /* read 2 samples from source */ in1 = *pSrc++; in2 = *pSrc++; #ifndef ARM_MATH_BIG_ENDIAN write_q15x2_ia (&pDst, __PKHBT((in1 >> -shiftBits), (in2 >> -shiftBits), 16)); #else write_q15x2_ia (&pDst, __PKHBT((in2 >> -shiftBits), (in1 >> -shiftBits), 16)); #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ #else *pDst++ = (*pSrc++ >> -shiftBits); *pDst++ = (*pSrc++ >> -shiftBits); *pDst++ = (*pSrc++ >> -shiftBits); *pDst++ = (*pSrc++ >> -shiftBits); #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) */ /* If the shift value is positive then do right shift else left shift */ if (sign == 0U) { while (blkCnt > 0U) { /* C = A << shiftBits */ /* Shift input and store result in destination buffer. */ *pDst++ = __SSAT(((q31_t) *pSrc++ << shiftBits), 16); /* Decrement loop counter */ blkCnt--; } } else { while (blkCnt > 0U) { /* C = A >> shiftBits */ /* Shift input and store result in destination buffer. */ *pDst++ = (*pSrc++ >> -shiftBits); /* Decrement loop counter */ blkCnt--; } } } #endif /* defined(ARM_MATH_MVEI) */ /** @} end of BasicShift group */