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git.gir.st - tmk_keyboard.git/blob - tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/ComplexMathFunctions/arm_cmplx_mag_squared_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_cmplx_mag_squared_q31.c
10 * Description: Q31 complex magnitude squared.
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 groupCmplxMath
48 * @addtogroup cmplx_mag_squared
54 * @brief Q31 complex magnitude squared
55 * @param *pSrc points to the complex input vector
56 * @param *pDst points to the real output vector
57 * @param numSamples number of complex samples in the input vector
60 * <b>Scaling and Overflow Behavior:</b>
62 * The function implements 1.31 by 1.31 multiplications and finally output is converted into 3.29 format.
63 * Input down scaling is not required.
66 void arm_cmplx_mag_squared_q31(
71 q31_t real
, imag
; /* Temporary variables to store real and imaginary values */
72 q31_t acc0
, acc1
; /* Accumulators */
74 #ifndef ARM_MATH_CM0_FAMILY
76 /* Run the below code for Cortex-M4 and Cortex-M3 */
77 uint32_t blkCnt
; /* loop counter */
80 blkCnt
= numSamples
>> 2u;
82 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
83 ** a second loop below computes the remaining 1 to 3 samples. */
86 /* C[0] = (A[0] * A[0] + A[1] * A[1]) */
89 acc0
= (q31_t
) (((q63_t
) real
* real
) >> 33);
90 acc1
= (q31_t
) (((q63_t
) imag
* imag
) >> 33);
91 /* store the result in 3.29 format in the destination buffer. */
92 *pDst
++ = acc0
+ acc1
;
96 acc0
= (q31_t
) (((q63_t
) real
* real
) >> 33);
97 acc1
= (q31_t
) (((q63_t
) imag
* imag
) >> 33);
98 /* store the result in 3.29 format in the destination buffer. */
99 *pDst
++ = acc0
+ acc1
;
103 acc0
= (q31_t
) (((q63_t
) real
* real
) >> 33);
104 acc1
= (q31_t
) (((q63_t
) imag
* imag
) >> 33);
105 /* store the result in 3.29 format in the destination buffer. */
106 *pDst
++ = acc0
+ acc1
;
110 acc0
= (q31_t
) (((q63_t
) real
* real
) >> 33);
111 acc1
= (q31_t
) (((q63_t
) imag
* imag
) >> 33);
112 /* store the result in 3.29 format in the destination buffer. */
113 *pDst
++ = acc0
+ acc1
;
115 /* Decrement the loop counter */
119 /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
120 ** No loop unrolling is used. */
121 blkCnt
= numSamples
% 0x4u
;
125 /* C[0] = (A[0] * A[0] + A[1] * A[1]) */
128 acc0
= (q31_t
) (((q63_t
) real
* real
) >> 33);
129 acc1
= (q31_t
) (((q63_t
) imag
* imag
) >> 33);
130 /* store the result in 3.29 format in the destination buffer. */
131 *pDst
++ = acc0
+ acc1
;
133 /* Decrement the loop counter */
139 /* Run the below code for Cortex-M0 */
141 while(numSamples
> 0u)
143 /* out = ((real * real) + (imag * imag)) */
146 acc0
= (q31_t
) (((q63_t
) real
* real
) >> 33);
147 acc1
= (q31_t
) (((q63_t
) imag
* imag
) >> 33);
148 /* store the result in 3.29 format in the destination buffer. */
149 *pDst
++ = acc0
+ acc1
;
151 /* Decrement the loop counter */
155 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
160 * @} end of cmplx_mag_squared group