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git.gir.st - tmk_keyboard.git/blob - tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/SupportFunctions/arm_float_to_q31.c
1 /* ----------------------------------------------------------------------------
2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
4 * $Date: 17. January 2013
7 * Project: CMSIS DSP Library
8 * Title: arm_float_to_q31.c
10 * Description: Converts the elements of the floating-point vector to Q31 vector.
12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
17 * - Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * - Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in
21 * the documentation and/or other materials provided with the
23 * - Neither the name of ARM LIMITED nor the names of its contributors
24 * may be used to endorse or promote products derived from this
25 * software without specific prior written permission.
27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
38 * POSSIBILITY OF SUCH DAMAGE.
39 * ---------------------------------------------------------------------------- */
44 * @ingroup groupSupport
48 * @defgroup float_to_x Convert 32-bit floating point value
52 * @addtogroup float_to_x
57 * @brief Converts the elements of the floating-point vector to Q31 vector.
58 * @param[in] *pSrc points to the floating-point input vector
59 * @param[out] *pDst points to the Q31 output vector
60 * @param[in] blockSize length of the input vector
65 * The equation used for the conversion process is:
68 * pDst[n] = (q31_t)(pSrc[n] * 2147483648); 0 <= n < blockSize.
70 * <b>Scaling and Overflow Behavior:</b>
72 * The function uses saturating arithmetic.
73 * Results outside of the allowable Q31 range[0x80000000 0x7FFFFFFF] will be saturated.
75 * \note In order to apply rounding, the library should be rebuilt with the ROUNDING macro
76 * defined in the preprocessor section of project options.
80 void arm_float_to_q31(
85 float32_t
*pIn
= pSrc
; /* Src pointer */
86 uint32_t blkCnt
; /* loop counter */
88 #ifdef ARM_MATH_ROUNDING
92 #endif /* #ifdef ARM_MATH_ROUNDING */
94 #ifndef ARM_MATH_CM0_FAMILY
96 /* Run the below code for Cortex-M4 and Cortex-M3 */
99 blkCnt
= blockSize
>> 2u;
101 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
102 ** a second loop below computes the remaining 1 to 3 samples. */
106 #ifdef ARM_MATH_ROUNDING
109 /* convert from float to Q31 and then store the results in the destination buffer */
111 in
= (in
* 2147483648.0f
);
112 in
+= in
> 0 ? 0.5 : -0.5;
113 *pDst
++ = clip_q63_to_q31((q63_t
) (in
));
116 in
= (in
* 2147483648.0f
);
117 in
+= in
> 0 ? 0.5 : -0.5;
118 *pDst
++ = clip_q63_to_q31((q63_t
) (in
));
121 in
= (in
* 2147483648.0f
);
122 in
+= in
> 0 ? 0.5 : -0.5;
123 *pDst
++ = clip_q63_to_q31((q63_t
) (in
));
126 in
= (in
* 2147483648.0f
);
127 in
+= in
> 0 ? 0.5 : -0.5;
128 *pDst
++ = clip_q63_to_q31((q63_t
) (in
));
132 /* C = A * 2147483648 */
133 /* convert from float to Q31 and then store the results in the destination buffer */
134 *pDst
++ = clip_q63_to_q31((q63_t
) (*pIn
++ * 2147483648.0f
));
135 *pDst
++ = clip_q63_to_q31((q63_t
) (*pIn
++ * 2147483648.0f
));
136 *pDst
++ = clip_q63_to_q31((q63_t
) (*pIn
++ * 2147483648.0f
));
137 *pDst
++ = clip_q63_to_q31((q63_t
) (*pIn
++ * 2147483648.0f
));
139 #endif /* #ifdef ARM_MATH_ROUNDING */
141 /* Decrement the loop counter */
145 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
146 ** No loop unrolling is used. */
147 blkCnt
= blockSize
% 0x4u
;
152 #ifdef ARM_MATH_ROUNDING
154 /* C = A * 2147483648 */
155 /* convert from float to Q31 and then store the results in the destination buffer */
157 in
= (in
* 2147483648.0f
);
158 in
+= in
> 0 ? 0.5 : -0.5;
159 *pDst
++ = clip_q63_to_q31((q63_t
) (in
));
163 /* C = A * 2147483648 */
164 /* convert from float to Q31 and then store the results in the destination buffer */
165 *pDst
++ = clip_q63_to_q31((q63_t
) (*pIn
++ * 2147483648.0f
));
167 #endif /* #ifdef ARM_MATH_ROUNDING */
169 /* Decrement the loop counter */
176 /* Run the below code for Cortex-M0 */
178 /* Loop over blockSize number of values */
184 #ifdef ARM_MATH_ROUNDING
186 /* C = A * 2147483648 */
187 /* convert from float to Q31 and then store the results in the destination buffer */
189 in
= (in
* 2147483648.0f
);
190 in
+= in
> 0 ? 0.5f
: -0.5f
;
191 *pDst
++ = clip_q63_to_q31((q63_t
) (in
));
195 /* C = A * 2147483648 */
196 /* convert from float to Q31 and then store the results in the destination buffer */
197 *pDst
++ = clip_q63_to_q31((q63_t
) (*pIn
++ * 2147483648.0f
));
199 #endif /* #ifdef ARM_MATH_ROUNDING */
201 /* Decrement the loop counter */
205 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
210 * @} end of float_to_x group