/* ---------------------------------------------------------------------- * Project: CMSIS DSP Library * Title: arm_float_to_q15.c * Description: Converts the elements of the floating-point vector to Q15 vector * * $Date: 27. January 2017 * $Revision: V.1.5.1 * * Target Processor: Cortex-M cores * -------------------------------------------------------------------- */ /* * Copyright (C) 2010-2017 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 length of the input vector * @return none. * * \par Description: * \par * The equation used for the conversion process is: *
 * 	pDst[n] = (q15_t)(pSrc[n] * 32768);   0 <= n < blockSize.
 * 
* \par Scaling and Overflow Behavior: * \par * The function uses saturating arithmetic. * Results outside of the allowable Q15 range [0x8000 0x7FFF] will be saturated. * \note * In order to apply rounding, the library should be rebuilt with the ROUNDING macro * defined in the preprocessor section of project options. * */ void arm_float_to_q15( float32_t * pSrc, q15_t * pDst, uint32_t blockSize) { float32_t *pIn = pSrc; /* Src pointer */ uint32_t blkCnt; /* loop counter */ #ifdef ARM_MATH_ROUNDING float32_t in; #endif /* #ifdef ARM_MATH_ROUNDING */ #if defined (ARM_MATH_DSP) /* Run the below code for Cortex-M4 and Cortex-M3 */ /*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) { #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)); in = *pIn++; in = (in * 32768.0f); in += in > 0.0f ? 0.5f : -0.5f; *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16)); in = *pIn++; in = (in * 32768.0f); in += in > 0.0f ? 0.5f : -0.5f; *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16)); 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); *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 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; 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 /* Run the below code for Cortex-M0 */ /* Loop over blockSize number of values */ blkCnt = blockSize; 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 ? 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--; } #endif /* #if defined (ARM_MATH_DSP) */ } /** * @} end of float_to_x group */