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git.gir.st - tmk_keyboard.git/blob - tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/BasicMathFunctions/arm_abs_q15.c
1 /* ----------------------------------------------------------------------
2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
4 * $Date: 17. January 2013
7 * Project: CMSIS DSP Library
10 * Description: Q15 vector absolute value.
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 * -------------------------------------------------------------------- */
48 * @addtogroup BasicAbs
53 * @brief Q15 vector absolute value.
54 * @param[in] *pSrc points to the input buffer
55 * @param[out] *pDst points to the output buffer
56 * @param[in] blockSize number of samples in each vector
59 * <b>Scaling and Overflow Behavior:</b>
61 * The function uses saturating arithmetic.
62 * The Q15 value -1 (0x8000) will be saturated to the maximum allowable positive value 0x7FFF.
70 uint32_t blkCnt
; /* loop counter */
72 #ifndef ARM_MATH_CM0_FAMILY
75 /* Run the below code for Cortex-M4 and Cortex-M3 */
77 q15_t in1
; /* Input value1 */
78 q15_t in2
; /* Input value2 */
82 blkCnt
= blockSize
>> 2u;
84 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
85 ** a second loop below computes the remaining 1 to 3 samples. */
86 simd
= __SIMD32_CONST(pDst
);
95 /* Store the Absolute result in the destination buffer by packing the two values, in a single cycle */
96 #ifndef ARM_MATH_BIG_ENDIAN
98 __PKHBT(((in1
> 0) ? in1
: (q15_t
)__QSUB16(0, in1
)),
99 ((in2
> 0) ? in2
: (q15_t
)__QSUB16(0, in2
)), 16);
105 __PKHBT(((in2
> 0) ? in2
: (q15_t
)__QSUB16(0, in2
)),
106 ((in1
> 0) ? in1
: (q15_t
)__QSUB16(0, in1
)), 16);
108 #endif /* #ifndef ARM_MATH_BIG_ENDIAN */
114 #ifndef ARM_MATH_BIG_ENDIAN
117 __PKHBT(((in1
> 0) ? in1
: (q15_t
)__QSUB16(0, in1
)),
118 ((in2
> 0) ? in2
: (q15_t
)__QSUB16(0, in2
)), 16);
124 __PKHBT(((in2
> 0) ? in2
: (q15_t
)__QSUB16(0, in2
)),
125 ((in1
> 0) ? in1
: (q15_t
)__QSUB16(0, in1
)), 16);
127 #endif /* #ifndef ARM_MATH_BIG_ENDIAN */
129 /* Decrement the loop counter */
132 pDst
= (q15_t
*)simd
;
134 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
135 ** No loop unrolling is used. */
136 blkCnt
= blockSize
% 0x4u
;
144 /* Calculate absolute value of input and then store the result in the destination buffer. */
145 *pDst
++ = (in1
> 0) ? in1
: (q15_t
)__QSUB16(0, in1
);
147 /* Decrement the loop counter */
153 /* Run the below code for Cortex-M0 */
155 q15_t in
; /* Temporary input variable */
157 /* Initialize blkCnt with number of samples */
166 /* Calculate absolute value of input and then store the result in the destination buffer. */
167 *pDst
++ = (in
> 0) ? in
: ((in
== (q15_t
) 0x8000) ? 0x7fff : -in
);
169 /* Decrement the loop counter */
173 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
178 * @} end of BasicAbs group