/* ---------------------------------------------------------------------- * Project: CMSIS DSP Library * Title: arm_float_to_q31.c * Description: Converts the elements of the floating-point vector to Q31 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 */ /** * @defgroup float_to_x Convert 32-bit floating point value */ /** @addtogroup float_to_x @{ */ /** @brief Converts the elements of the floating-point vector to Q31 vector. @param[in] pSrc points to the floating-point input vector @param[out] pDst points to the Q31 output vector @param[in] blockSize number of samples in each vector @return none @par Details The equation used for the conversion process is: 
      pDst[n] = (q31_t)(pSrc[n] * 2147483648);   0 <= n < blockSize.
@par Scaling and Overflow Behavior The function uses saturating arithmetic. Results outside of the allowable Q31 range[0x80000000 0x7FFFFFFF] 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) void arm_float_to_q31( const float32_t * pSrc, q31_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 / 2147483648.0f); float32x4_t mHalf = vdupq_n_f32(-0.5f / 2147483648.0f); float32x4_t r; uint32x4_t cmp; #endif int32x4_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 Q31 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; outV = vcvtq_n_s32_f32(inV,31); vst1q_s32(pDst, outV); pDst += 4; #else /* C = A * 2147483648 */ /* Convert from float to Q31 and then store the results in the destination buffer */ inV = vld1q_f32(pIn); outV = vcvtq_n_s32_f32(inV,31); vst1q_s32(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 * 2147483648 */ /* Convert from float to Q31 and then store the results in the destination buffer */ in = *pIn++; in = (in * 2147483648.0f); in += in > 0.0f ? 0.5f : -0.5f; *pDst++ = clip_q63_to_q31((q63_t) (in)); #else /* C = A * 2147483648 */ /* Convert from float to Q31 and then store the results in the destination buffer */ *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f)); #endif /* #ifdef ARM_MATH_ROUNDING */ /* Decrement the loop counter */ blkCnt--; } } #else void arm_float_to_q31( const float32_t * pSrc, q31_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 * 2147483648 */ /* convert from float to Q31 and store result in destination buffer */ #ifdef ARM_MATH_ROUNDING in = (*pIn++ * 2147483648.0f); in += in > 0.0f ? 0.5f : -0.5f; *pDst++ = clip_q63_to_q31((q63_t) (in)); in = (*pIn++ * 2147483648.0f); in += in > 0.0f ? 0.5f : -0.5f; *pDst++ = clip_q63_to_q31((q63_t) (in)); in = (*pIn++ * 2147483648.0f); in += in > 0.0f ? 0.5f : -0.5f; *pDst++ = clip_q63_to_q31((q63_t) (in)); in = (*pIn++ * 2147483648.0f); in += in > 0.0f ? 0.5f : -0.5f; *pDst++ = clip_q63_to_q31((q63_t) (in)); #else /* C = A * 2147483648 */ /* Convert from float to Q31 and then store the results in the destination buffer */ *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f)); *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f)); *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f)); *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f)); #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 * 2147483648 */ /* convert from float to Q31 and store result in destination buffer */ #ifdef ARM_MATH_ROUNDING in = (*pIn++ * 2147483648.0f); in += in > 0.0f ? 0.5f : -0.5f; *pDst++ = clip_q63_to_q31((q63_t) (in)); #else /* C = A * 2147483648 */ /* Convert from float to Q31 and then store the results in the destination buffer */ *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f)); #endif /* #ifdef ARM_MATH_ROUNDING */ /* Decrement loop counter */ blkCnt--; } } #endif /* #if defined(ARM_MATH_NEON) */ /** @} end of float_to_x group */