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CMSIS DSP library

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cmsis_dsp/SupportFunctions/arm_float_to_q31.c@2:da51fb522205, 2013-05-30 (annotated)

Committer:
emilmont
Date:
Thu May 30 17:10:11 2013 +0100
Revision:
2:da51fb522205
Parent:
1:fdd22bb7aa52
Child:
3:7a284390b0ce
Keep "cmsis-dsp" module in synch with its source

Who changed what in which revision?

UserRevisionLine numberNew contents of line
emilmont 1:fdd22bb7aa52 1 /* ----------------------------------------------------------------------------
emilmont 1:fdd22bb7aa52 2 * Copyright (C) 2010 ARM Limited. All rights reserved.
emilmont 1:fdd22bb7aa52 3 *
emilmont 1:fdd22bb7aa52 4 * $Date: 15. February 2012
emilmont 2:da51fb522205 5 * $Revision: V1.1.0
emilmont 1:fdd22bb7aa52 6 *
emilmont 2:da51fb522205 7 * Project: CMSIS DSP Library
emilmont 2:da51fb522205 8 * Title: arm_float_to_q31.c
emilmont 1:fdd22bb7aa52 9 *
emilmont 2:da51fb522205 10 * Description: Converts the elements of the floating-point vector to Q31 vector.
emilmont 1:fdd22bb7aa52 11 *
emilmont 1:fdd22bb7aa52 12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
emilmont 1:fdd22bb7aa52 13 *
emilmont 1:fdd22bb7aa52 14 * Version 1.1.0 2012/02/15
emilmont 1:fdd22bb7aa52 15 * Updated with more optimizations, bug fixes and minor API changes.
emilmont 1:fdd22bb7aa52 16 *
emilmont 1:fdd22bb7aa52 17 * Version 1.0.10 2011/7/15
emilmont 1:fdd22bb7aa52 18 * Big Endian support added and Merged M0 and M3/M4 Source code.
emilmont 1:fdd22bb7aa52 19 *
emilmont 1:fdd22bb7aa52 20 * Version 1.0.3 2010/11/29
emilmont 1:fdd22bb7aa52 21 * Re-organized the CMSIS folders and updated documentation.
emilmont 1:fdd22bb7aa52 22 *
emilmont 1:fdd22bb7aa52 23 * Version 1.0.2 2010/11/11
emilmont 1:fdd22bb7aa52 24 * Documentation updated.
emilmont 1:fdd22bb7aa52 25 *
emilmont 1:fdd22bb7aa52 26 * Version 1.0.1 2010/10/05
emilmont 1:fdd22bb7aa52 27 * Production release and review comments incorporated.
emilmont 1:fdd22bb7aa52 28 *
emilmont 1:fdd22bb7aa52 29 * Version 1.0.0 2010/09/20
emilmont 1:fdd22bb7aa52 30 * Production release and review comments incorporated.
emilmont 1:fdd22bb7aa52 31 * ---------------------------------------------------------------------------- */
emilmont 1:fdd22bb7aa52 32
emilmont 1:fdd22bb7aa52 33 #include "arm_math.h"
emilmont 1:fdd22bb7aa52 34
emilmont 1:fdd22bb7aa52 35 /**
emilmont 1:fdd22bb7aa52 36 * @ingroup groupSupport
emilmont 1:fdd22bb7aa52 37 */
emilmont 1:fdd22bb7aa52 38
emilmont 1:fdd22bb7aa52 39 /**
emilmont 1:fdd22bb7aa52 40 * @defgroup float_to_x Convert 32-bit floating point value
emilmont 1:fdd22bb7aa52 41 */
emilmont 1:fdd22bb7aa52 42
emilmont 1:fdd22bb7aa52 43 /**
emilmont 1:fdd22bb7aa52 44 * @addtogroup float_to_x
emilmont 1:fdd22bb7aa52 45 * @{
emilmont 1:fdd22bb7aa52 46 */
emilmont 1:fdd22bb7aa52 47
emilmont 1:fdd22bb7aa52 48 /**
emilmont 1:fdd22bb7aa52 49 * @brief Converts the elements of the floating-point vector to Q31 vector.
emilmont 1:fdd22bb7aa52 50 * @param[in] *pSrc points to the floating-point input vector
emilmont 1:fdd22bb7aa52 51 * @param[out] *pDst points to the Q31 output vector
emilmont 1:fdd22bb7aa52 52 * @param[in] blockSize length of the input vector
emilmont 1:fdd22bb7aa52 53 * @return none.
emilmont 1:fdd22bb7aa52 54 *
emilmont 1:fdd22bb7aa52 55 *\par Description:
emilmont 1:fdd22bb7aa52 56 * \par
emilmont 1:fdd22bb7aa52 57 * The equation used for the conversion process is:
emilmont 1:fdd22bb7aa52 58 *
emilmont 1:fdd22bb7aa52 59 * <pre>
emilmont 2:da51fb522205 60 * pDst[n] = (q31_t)(pSrc[n] * 2147483648); 0 <= n < blockSize.
emilmont 1:fdd22bb7aa52 61 * </pre>
emilmont 1:fdd22bb7aa52 62 * <b>Scaling and Overflow Behavior:</b>
emilmont 1:fdd22bb7aa52 63 * \par
emilmont 1:fdd22bb7aa52 64 * The function uses saturating arithmetic.
emilmont 1:fdd22bb7aa52 65 * Results outside of the allowable Q31 range[0x80000000 0x7FFFFFFF] will be saturated.
emilmont 1:fdd22bb7aa52 66 *
emilmont 1:fdd22bb7aa52 67 * \note In order to apply rounding, the library should be rebuilt with the ROUNDING macro
emilmont 1:fdd22bb7aa52 68 * defined in the preprocessor section of project options.
emilmont 1:fdd22bb7aa52 69 */
emilmont 1:fdd22bb7aa52 70
emilmont 1:fdd22bb7aa52 71
emilmont 1:fdd22bb7aa52 72 void arm_float_to_q31(
emilmont 1:fdd22bb7aa52 73 float32_t * pSrc,
emilmont 1:fdd22bb7aa52 74 q31_t * pDst,
emilmont 1:fdd22bb7aa52 75 uint32_t blockSize)
emilmont 1:fdd22bb7aa52 76 {
emilmont 1:fdd22bb7aa52 77 float32_t *pIn = pSrc; /* Src pointer */
emilmont 1:fdd22bb7aa52 78 uint32_t blkCnt; /* loop counter */
emilmont 1:fdd22bb7aa52 79
emilmont 1:fdd22bb7aa52 80 #ifdef ARM_MATH_ROUNDING
emilmont 1:fdd22bb7aa52 81
emilmont 1:fdd22bb7aa52 82 float32_t in;
emilmont 1:fdd22bb7aa52 83
emilmont 1:fdd22bb7aa52 84 #endif /* #ifdef ARM_MATH_ROUNDING */
emilmont 1:fdd22bb7aa52 85
emilmont 1:fdd22bb7aa52 86 #ifndef ARM_MATH_CM0
emilmont 1:fdd22bb7aa52 87
emilmont 1:fdd22bb7aa52 88 /* Run the below code for Cortex-M4 and Cortex-M3 */
emilmont 1:fdd22bb7aa52 89
emilmont 1:fdd22bb7aa52 90 /*loop Unrolling */
emilmont 1:fdd22bb7aa52 91 blkCnt = blockSize >> 2u;
emilmont 1:fdd22bb7aa52 92
emilmont 1:fdd22bb7aa52 93 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
emilmont 1:fdd22bb7aa52 94 ** a second loop below computes the remaining 1 to 3 samples. */
emilmont 1:fdd22bb7aa52 95 while(blkCnt > 0u)
emilmont 1:fdd22bb7aa52 96 {
emilmont 1:fdd22bb7aa52 97
emilmont 1:fdd22bb7aa52 98 #ifdef ARM_MATH_ROUNDING
emilmont 1:fdd22bb7aa52 99
emilmont 1:fdd22bb7aa52 100 /* C = A * 32768 */
emilmont 1:fdd22bb7aa52 101 /* convert from float to Q31 and then store the results in the destination buffer */
emilmont 1:fdd22bb7aa52 102 in = *pIn++;
emilmont 1:fdd22bb7aa52 103 in = (in * 2147483648.0f);
emilmont 1:fdd22bb7aa52 104 in += in > 0 ? 0.5 : -0.5;
emilmont 1:fdd22bb7aa52 105 *pDst++ = clip_q63_to_q31((q63_t) (in));
emilmont 1:fdd22bb7aa52 106
emilmont 1:fdd22bb7aa52 107 in = *pIn++;
emilmont 1:fdd22bb7aa52 108 in = (in * 2147483648.0f);
emilmont 1:fdd22bb7aa52 109 in += in > 0 ? 0.5 : -0.5;
emilmont 1:fdd22bb7aa52 110 *pDst++ = clip_q63_to_q31((q63_t) (in));
emilmont 1:fdd22bb7aa52 111
emilmont 1:fdd22bb7aa52 112 in = *pIn++;
emilmont 1:fdd22bb7aa52 113 in = (in * 2147483648.0f);
emilmont 1:fdd22bb7aa52 114 in += in > 0 ? 0.5 : -0.5;
emilmont 1:fdd22bb7aa52 115 *pDst++ = clip_q63_to_q31((q63_t) (in));
emilmont 1:fdd22bb7aa52 116
emilmont 1:fdd22bb7aa52 117 in = *pIn++;
emilmont 1:fdd22bb7aa52 118 in = (in * 2147483648.0f);
emilmont 1:fdd22bb7aa52 119 in += in > 0 ? 0.5 : -0.5;
emilmont 1:fdd22bb7aa52 120 *pDst++ = clip_q63_to_q31((q63_t) (in));
emilmont 1:fdd22bb7aa52 121
emilmont 1:fdd22bb7aa52 122 #else
emilmont 1:fdd22bb7aa52 123
emilmont 1:fdd22bb7aa52 124 /* C = A * 2147483648 */
emilmont 1:fdd22bb7aa52 125 /* convert from float to Q31 and then store the results in the destination buffer */
emilmont 1:fdd22bb7aa52 126 *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f));
emilmont 1:fdd22bb7aa52 127 *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f));
emilmont 1:fdd22bb7aa52 128 *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f));
emilmont 1:fdd22bb7aa52 129 *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f));
emilmont 1:fdd22bb7aa52 130
emilmont 1:fdd22bb7aa52 131 #endif /* #ifdef ARM_MATH_ROUNDING */
emilmont 1:fdd22bb7aa52 132
emilmont 1:fdd22bb7aa52 133 /* Decrement the loop counter */
emilmont 1:fdd22bb7aa52 134 blkCnt--;
emilmont 1:fdd22bb7aa52 135 }
emilmont 1:fdd22bb7aa52 136
emilmont 1:fdd22bb7aa52 137 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
emilmont 1:fdd22bb7aa52 138 ** No loop unrolling is used. */
emilmont 1:fdd22bb7aa52 139 blkCnt = blockSize % 0x4u;
emilmont 1:fdd22bb7aa52 140
emilmont 1:fdd22bb7aa52 141 while(blkCnt > 0u)
emilmont 1:fdd22bb7aa52 142 {
emilmont 1:fdd22bb7aa52 143
emilmont 1:fdd22bb7aa52 144 #ifdef ARM_MATH_ROUNDING
emilmont 1:fdd22bb7aa52 145
emilmont 1:fdd22bb7aa52 146 /* C = A * 2147483648 */
emilmont 1:fdd22bb7aa52 147 /* convert from float to Q31 and then store the results in the destination buffer */
emilmont 1:fdd22bb7aa52 148 in = *pIn++;
emilmont 1:fdd22bb7aa52 149 in = (in * 2147483648.0f);
emilmont 1:fdd22bb7aa52 150 in += in > 0 ? 0.5 : -0.5;
emilmont 1:fdd22bb7aa52 151 *pDst++ = clip_q63_to_q31((q63_t) (in));
emilmont 1:fdd22bb7aa52 152
emilmont 1:fdd22bb7aa52 153 #else
emilmont 1:fdd22bb7aa52 154
emilmont 1:fdd22bb7aa52 155 /* C = A * 2147483648 */
emilmont 1:fdd22bb7aa52 156 /* convert from float to Q31 and then store the results in the destination buffer */
emilmont 1:fdd22bb7aa52 157 *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f));
emilmont 1:fdd22bb7aa52 158
emilmont 1:fdd22bb7aa52 159 #endif /* #ifdef ARM_MATH_ROUNDING */
emilmont 1:fdd22bb7aa52 160
emilmont 1:fdd22bb7aa52 161 /* Decrement the loop counter */
emilmont 1:fdd22bb7aa52 162 blkCnt--;
emilmont 1:fdd22bb7aa52 163 }
emilmont 1:fdd22bb7aa52 164
emilmont 1:fdd22bb7aa52 165
emilmont 1:fdd22bb7aa52 166 #else
emilmont 1:fdd22bb7aa52 167
emilmont 1:fdd22bb7aa52 168 /* Run the below code for Cortex-M0 */
emilmont 1:fdd22bb7aa52 169
emilmont 1:fdd22bb7aa52 170 /* Loop over blockSize number of values */
emilmont 1:fdd22bb7aa52 171 blkCnt = blockSize;
emilmont 1:fdd22bb7aa52 172
emilmont 1:fdd22bb7aa52 173 while(blkCnt > 0u)
emilmont 1:fdd22bb7aa52 174 {
emilmont 1:fdd22bb7aa52 175
emilmont 1:fdd22bb7aa52 176 #ifdef ARM_MATH_ROUNDING
emilmont 1:fdd22bb7aa52 177
emilmont 1:fdd22bb7aa52 178 /* C = A * 2147483648 */
emilmont 1:fdd22bb7aa52 179 /* convert from float to Q31 and then store the results in the destination buffer */
emilmont 1:fdd22bb7aa52 180 in = *pIn++;
emilmont 1:fdd22bb7aa52 181 in = (in * 2147483648.0f);
emilmont 1:fdd22bb7aa52 182 in += in > 0 ? 0.5f : -0.5f;
emilmont 1:fdd22bb7aa52 183 *pDst++ = clip_q63_to_q31((q63_t) (in));
emilmont 1:fdd22bb7aa52 184
emilmont 1:fdd22bb7aa52 185 #else
emilmont 1:fdd22bb7aa52 186
emilmont 1:fdd22bb7aa52 187 /* C = A * 2147483648 */
emilmont 1:fdd22bb7aa52 188 /* convert from float to Q31 and then store the results in the destination buffer */
emilmont 1:fdd22bb7aa52 189 *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f));
emilmont 1:fdd22bb7aa52 190
emilmont 1:fdd22bb7aa52 191 #endif /* #ifdef ARM_MATH_ROUNDING */
emilmont 1:fdd22bb7aa52 192
emilmont 1:fdd22bb7aa52 193 /* Decrement the loop counter */
emilmont 1:fdd22bb7aa52 194 blkCnt--;
emilmont 1:fdd22bb7aa52 195 }
emilmont 1:fdd22bb7aa52 196
emilmont 1:fdd22bb7aa52 197 #endif /* #ifndef ARM_MATH_CM0 */
emilmont 1:fdd22bb7aa52 198
emilmont 1:fdd22bb7aa52 199 }
emilmont 1:fdd22bb7aa52 200
emilmont 1:fdd22bb7aa52 201 /**
emilmont 1:fdd22bb7aa52 202 * @} end of float_to_x group
emilmont 1:fdd22bb7aa52 203 */