| /* ---------------------------------------------------------------------- |
| * Project: CMSIS DSP Library |
| * Title: arm_float_to_q15.c |
| * Description: Converts the elements of the floating-point vector to Q15 vector |
| * |
| * $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 groupSupport |
| */ |
| |
| /** |
| @addtogroup float_to_x |
| @{ |
| */ |
| |
| /** |
| @brief Converts the elements of the floating-point vector to Q15 vector. |
| @param[in] pSrc points to the floating-point input vector |
| @param[out] pDst points to the Q15 output vector |
| @param[in] blockSize number of samples in each vector |
| @return none |
| |
| @par Details |
| The equation used for the conversion process is: |
| <pre> |
| pDst[n] = (q15_t)(pSrc[n] * 32768); 0 <= n < blockSize. |
| </pre> |
| |
| @par Scaling and Overflow Behavior |
| The function uses saturating arithmetic. |
| Results outside of the allowable Q15 range [0x8000 0x7FFF] are saturated. |
| |
| @note |
| In order to apply rounding, the library should be rebuilt with the ROUNDING macro |
| defined in the preprocessor section of project options. |
| */ |
| #if defined(ARM_MATH_NEON_EXPERIMENTAL) |
| void arm_float_to_q15( |
| const float32_t * pSrc, |
| q15_t * pDst, |
| uint32_t blockSize) |
| { |
| const float32_t *pIn = pSrc; /* Src pointer */ |
| uint32_t blkCnt; /* loop counter */ |
| |
| float32_t in; |
| float32x4_t inV; |
| #ifdef ARM_MATH_ROUNDING |
| float32x4_t zeroV = vdupq_n_f32(0.0f); |
| float32x4_t pHalf = vdupq_n_f32(0.5f / 32768.0f); |
| float32x4_t mHalf = vdupq_n_f32(-0.5f / 32768.0f); |
| float32x4_t r; |
| uint32x4_t cmp; |
| #endif |
| |
| int32x4_t cvt; |
| int16x4_t outV; |
| |
| blkCnt = blockSize >> 2U; |
| |
| /* Compute 4 outputs at a time. |
| ** a second loop below computes the remaining 1 to 3 samples. */ |
| while (blkCnt > 0U) |
| { |
| |
| #ifdef ARM_MATH_ROUNDING |
| /* C = A * 32768 */ |
| /* Convert from float to q15 and then store the results in the destination buffer */ |
| inV = vld1q_f32(pIn); |
| cmp = vcgtq_f32(inV,zeroV); |
| r = vbslq_f32(cmp,pHalf,mHalf); |
| inV = vaddq_f32(inV, r); |
| |
| pIn += 4; |
| |
| cvt = vcvtq_n_s32_f32(inV,15); |
| outV = vqmovn_s32(cvt); |
| |
| vst1_s16(pDst, outV); |
| pDst += 4; |
| |
| #else |
| |
| /* C = A * 32768 */ |
| /* Convert from float to q15 and then store the results in the destination buffer */ |
| inV = vld1q_f32(pIn); |
| |
| cvt = vcvtq_n_s32_f32(inV,15); |
| outV = vqmovn_s32(cvt); |
| |
| vst1_s16(pDst, outV); |
| pDst += 4; |
| pIn += 4; |
| |
| #endif /* #ifdef ARM_MATH_ROUNDING */ |
| |
| /* 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 & 3; |
| |
| while (blkCnt > 0U) |
| { |
| |
| #ifdef ARM_MATH_ROUNDING |
| /* C = A * 32768 */ |
| /* Convert from float to q15 and then store the results in the destination buffer */ |
| in = *pIn++; |
| in = (in * 32768.0f); |
| in += in > 0.0f ? 0.5f : -0.5f; |
| *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16)); |
| |
| #else |
| |
| /* C = A * 32768 */ |
| /* Convert from float to q15 and then store the results in the destination buffer */ |
| *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16); |
| |
| #endif /* #ifdef ARM_MATH_ROUNDING */ |
| |
| /* Decrement the loop counter */ |
| blkCnt--; |
| } |
| } |
| #else |
| void arm_float_to_q15( |
| const float32_t * pSrc, |
| q15_t * pDst, |
| uint32_t blockSize) |
| { |
| uint32_t blkCnt; /* Loop counter */ |
| const float32_t *pIn = pSrc; /* Source pointer */ |
| |
| #ifdef ARM_MATH_ROUNDING |
| float32_t in; |
| #endif /* #ifdef ARM_MATH_ROUNDING */ |
| |
| #if defined (ARM_MATH_LOOPUNROLL) |
| |
| /* Loop unrolling: Compute 4 outputs at a time */ |
| blkCnt = blockSize >> 2U; |
| |
| while (blkCnt > 0U) |
| { |
| /* C = A * 32768 */ |
| |
| /* convert from float to Q15 and store result in destination buffer */ |
| #ifdef ARM_MATH_ROUNDING |
| |
| in = (*pIn++ * 32768.0f); |
| in += in > 0.0f ? 0.5f : -0.5f; |
| *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16)); |
| |
| in = (*pIn++ * 32768.0f); |
| in += in > 0.0f ? 0.5f : -0.5f; |
| *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16)); |
| |
| in = (*pIn++ * 32768.0f); |
| in += in > 0.0f ? 0.5f : -0.5f; |
| *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16)); |
| |
| in = (*pIn++ * 32768.0f); |
| in += in > 0.0f ? 0.5f : -0.5f; |
| *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16)); |
| |
| #else |
| |
| *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16); |
| *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16); |
| *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16); |
| *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16); |
| |
| #endif /* #ifdef ARM_MATH_ROUNDING */ |
| |
| /* 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 * 32768 */ |
| |
| /* convert from float to Q15 and store result in destination buffer */ |
| #ifdef ARM_MATH_ROUNDING |
| |
| in = (*pIn++ * 32768.0f); |
| in += in > 0.0f ? 0.5f : -0.5f; |
| *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16)); |
| |
| #else |
| |
| /* C = A * 32768 */ |
| /* Convert from float to q15 and then store the results in the destination buffer */ |
| *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16); |
| |
| #endif /* #ifdef ARM_MATH_ROUNDING */ |
| |
| /* Decrement loop counter */ |
| blkCnt--; |
| } |
| |
| } |
| #endif /* #if defined(ARM_MATH_NEON) */ |
| |
| /** |
| @} end of float_to_x group |
| */ |