| /* ---------------------------------------------------------------------------- |
| * Copyright (C) 2010 ARM Limited. All rights reserved. |
| * |
| * $Date: 15. July 2011 |
| * $Revision: V1.0.10 |
| * |
| * Project: CMSIS DSP Library |
| * Title: arm_float_to_q31.c |
| * |
| * Description: Converts the elements of the floating-point vector to Q31 vector. |
| * |
| * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 |
| * |
| * Version 1.0.10 2011/7/15 |
| * Big Endian support added and Merged M0 and M3/M4 Source code. |
| * |
| * Version 1.0.3 2010/11/29 |
| * Re-organized the CMSIS folders and updated documentation. |
| * |
| * Version 1.0.2 2010/11/11 |
| * Documentation updated. |
| * |
| * Version 1.0.1 2010/10/05 |
| * Production release and review comments incorporated. |
| * |
| * Version 1.0.0 2010/09/20 |
| * Production release and review comments incorporated. |
| * ---------------------------------------------------------------------------- */ |
| |
| #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 length of the input vector |
| * @return none. |
| * |
| *\par Description: |
| * \par |
| * The equation used for the conversion process is: |
| * |
| * <pre> |
| * pDst[n] = (q31_t)(pSrc[n] * 2147483648); 0 <= n < blockSize. |
| * </pre> |
| * <b>Scaling and Overflow Behavior:</b> |
| * \par |
| * The function uses saturating arithmetic. |
| * Results outside of the allowable Q31 range[0x80000000 0x7FFFFFFF] 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_q31( |
| float32_t * pSrc, |
| q31_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 */ |
| |
| #ifndef ARM_MATH_CM0 |
| |
| /* 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 Q31 and then store the results in the destination buffer */ |
| in = *pIn++; |
| in = (in * 2147483648.0f); |
| in += in > 0 ? 0.5 : -0.5; |
| *pDst++ = clip_q63_to_q31((q63_t) (in)); |
| |
| in = *pIn++; |
| in = (in * 2147483648.0f); |
| in += in > 0 ? 0.5 : -0.5; |
| *pDst++ = clip_q63_to_q31((q63_t) (in)); |
| |
| in = *pIn++; |
| in = (in * 2147483648.0f); |
| in += in > 0 ? 0.5 : -0.5; |
| *pDst++ = clip_q63_to_q31((q63_t) (in)); |
| |
| in = *pIn++; |
| in = (in * 2147483648.0f); |
| in += in > 0 ? 0.5 : -0.5; |
| *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 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 * 2147483648 */ |
| /* convert from float to Q31 and then store the results in the destination buffer */ |
| in = *pIn++; |
| in = (in * 2147483648.0f); |
| in += in > 0 ? 0.5 : -0.5; |
| *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 |
| |
| /* Run the below code for Cortex-M0 */ |
| |
| /* Loop over blockSize number of values */ |
| blkCnt = blockSize; |
| |
| 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 ? 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--; |
| } |
| |
| #endif /* #ifndef ARM_MATH_CM0 */ |
| |
| } |
| |
| /** |
| * @} end of float_to_x group |
| */ |