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git.gir.st - tmk_keyboard.git/blob - tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/BasicMathFunctions/arm_scale_q7.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_scale_q7.c
10 * Description: Multiplies a Q7 vector by a scalar.
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 * -------------------------------------------------------------------- */
53 * @brief Multiplies a Q7 vector by a scalar.
54 * @param[in] *pSrc points to the input vector
55 * @param[in] scaleFract fractional portion of the scale value
56 * @param[in] shift number of bits to shift the result by
57 * @param[out] *pDst points to the output vector
58 * @param[in] blockSize number of samples in the vector
61 * <b>Scaling and Overflow Behavior:</b>
63 * The input data <code>*pSrc</code> and <code>scaleFract</code> are in 1.7 format.
64 * These are multiplied to yield a 2.14 intermediate result and this is shifted with saturation to 1.7 format.
74 int8_t kShift
= 7 - shift
; /* shift to apply after scaling */
75 uint32_t blkCnt
; /* loop counter */
77 #ifndef ARM_MATH_CM0_FAMILY
79 /* Run the below code for Cortex-M4 and Cortex-M3 */
80 q7_t in1
, in2
, in3
, in4
, out1
, out2
, out3
, out4
; /* Temporary variables to store input & output */
84 blkCnt
= blockSize
>> 2u;
87 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
88 ** a second loop below computes the remaining 1 to 3 samples. */
91 /* Reading 4 inputs from memory */
98 /* Scale the inputs and then store the results in the temporary variables. */
99 out1
= (q7_t
) (__SSAT(((in1
) * scaleFract
) >> kShift
, 8));
100 out2
= (q7_t
) (__SSAT(((in2
) * scaleFract
) >> kShift
, 8));
101 out3
= (q7_t
) (__SSAT(((in3
) * scaleFract
) >> kShift
, 8));
102 out4
= (q7_t
) (__SSAT(((in4
) * scaleFract
) >> kShift
, 8));
104 /* Packing the individual outputs into 32bit and storing in
105 * destination buffer in single write */
106 *__SIMD32(pDst
)++ = __PACKq7(out1
, out2
, out3
, out4
);
108 /* Decrement the loop counter */
112 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
113 ** No loop unrolling is used. */
114 blkCnt
= blockSize
% 0x4u
;
119 /* Scale the input and then store the result in the destination buffer. */
120 *pDst
++ = (q7_t
) (__SSAT(((*pSrc
++) * scaleFract
) >> kShift
, 8));
122 /* Decrement the loop counter */
128 /* Run the below code for Cortex-M0 */
130 /* Initialize blkCnt with number of samples */
136 /* Scale the input and then store the result in the destination buffer. */
137 *pDst
++ = (q7_t
) (__SSAT((((q15_t
) * pSrc
++ * scaleFract
) >> kShift
), 8));
139 /* Decrement the loop counter */
143 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
148 * @} end of scale group