1 /* ----------------------------------------------------------------------
4  * Description:  Radix-2 Decimation in Frequency CFFT & CIFFT Fixed point processing function
9  * Target Processor: Cortex-M and Cortex-A cores
10  * -------------------------------------------------------------------- */
12  * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
14  * SPDX-License-Identifier: Apache-2.0
20  * www.apache.org/licenses/LICENSE-2.0
56   @brief         Processing function for the fixed-point CFFT/CIFFT.
58   @param[in]     S    points to an instance of the fixed-point CFFT/CIFFT structure
59 …t] pSrc points to the complex data buffer of size <code>2*fftLen</code>. Processing occurs in-place
67   if (S->ifftFlag == 1U)  in arm_cfft_radix2_q15()
69     arm_radix2_butterfly_inverse_q15 (pSrc, S->fftLen, S->pTwiddle, S->twidCoefModifier);  in arm_cfft_radix2_q15()
73     arm_radix2_butterfly_q15 (pSrc, S->fftLen, S->pTwiddle, S->twidCoefModifier);  in arm_cfft_radix2_q15()
76   arm_bitreversal_q15(pSrc, S->fftLen, S->bitRevFactor, S->pBitRevTable);  in arm_cfft_radix2_q15()
94   q31_t T, S, R;  in arm_radix2_butterfly_q15()  local
113     T = read_q15x2 (pSrc + (2 * i));  in arm_radix2_butterfly_q15()
114     in = ((int16_t) (T & 0xFFFF)) >> 1;  in arm_radix2_butterfly_q15()
115     T = ((T >> 1) & 0xFFFF0000) | (in & 0xFFFF);  in arm_radix2_butterfly_q15()
121     R = __QSUB16(T, S);  in arm_radix2_butterfly_q15()
123     write_q15x2 (pSrc + (2 * i), __SHADD16(T, S));  in arm_radix2_butterfly_q15()
143     T = read_q15x2 (pSrc + (2 * i));  in arm_radix2_butterfly_q15()
144     in = ((int16_t) (T & 0xFFFF)) >> 1;  in arm_radix2_butterfly_q15()
145     T = ((T >> 1) & 0xFFFF0000) | (in & 0xFFFF);  in arm_radix2_butterfly_q15()
151     R = __QSUB16(T, S);  in arm_radix2_butterfly_q15()
153     write_q15x2 (pSrc + (2 * i), __SHADD16(T, S));  in arm_radix2_butterfly_q15()
189         T = read_q15x2 (pSrc + (2 * i));  in arm_radix2_butterfly_q15()
193         R = __QSUB16(T, S);  in arm_radix2_butterfly_q15()
195         write_q15x2 (pSrc + (2 * i), __SHADD16(T, S));  in arm_radix2_butterfly_q15()
211         T = read_q15x2 (pSrc + (2 * i));  in arm_radix2_butterfly_q15()
215         R = __QSUB16(T, S);  in arm_radix2_butterfly_q15()
217         write_q15x2 (pSrc + (2 * i), __SHADD16(T, S));  in arm_radix2_butterfly_q15()
249     T = read_q15x2 (pSrc + (2 * i));  in arm_radix2_butterfly_q15()
253     R = __QSUB16(T, S);  in arm_radix2_butterfly_q15()
255     write_q15x2 (pSrc + (2 * i), __QADD16(T, S));  in arm_radix2_butterfly_q15()
262     T = read_q15x2 (pSrc + (2 * i));  in arm_radix2_butterfly_q15()
266     R = __QSUB16(T, S);  in arm_radix2_butterfly_q15()
268     write_q15x2 (pSrc + (2 * i), __QADD16(T, S));  in arm_radix2_butterfly_q15()
300       xt = (pSrc[2 * i] >> 1U) - (pSrc[2 * l] >> 1U);  in arm_radix2_butterfly_q15()
303       yt = (pSrc[2 * i + 1] >> 1U) - (pSrc[2 * l + 1] >> 1U);  in arm_radix2_butterfly_q15()
310       pSrc[2U * l + 1] = (((int16_t) (((q31_t) yt * cosVal) >> 16)) -  in arm_radix2_butterfly_q15()
337         xt = pSrc[2 * i] - pSrc[2 * l];  in arm_radix2_butterfly_q15()
340         yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];  in arm_radix2_butterfly_q15()
346         pSrc[2U * l + 1] = (((int16_t) (((q31_t) yt * cosVal) >> 16)) -  in arm_radix2_butterfly_q15()
372       xt = pSrc[2 * i] - pSrc[2 * l];  in arm_radix2_butterfly_q15()
375       yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];  in arm_radix2_butterfly_q15()
404         q31_t T, S, R;  in arm_radix2_butterfly_inverse_q15()  local
423     T = read_q15x2 (pSrc + (2 * i));  in arm_radix2_butterfly_inverse_q15()
424     in = ((int16_t) (T & 0xFFFF)) >> 1;  in arm_radix2_butterfly_inverse_q15()
425     T = ((T >> 1) & 0xFFFF0000) | (in & 0xFFFF);  in arm_radix2_butterfly_inverse_q15()
431     R = __QSUB16(T, S);  in arm_radix2_butterfly_inverse_q15()
433     write_q15x2 (pSrc + (2 * i), __SHADD16(T, S));  in arm_radix2_butterfly_inverse_q15()
453     T = read_q15x2 (pSrc + (2 * i));  in arm_radix2_butterfly_inverse_q15()
454     in = ((int16_t) (T & 0xFFFF)) >> 1;  in arm_radix2_butterfly_inverse_q15()
455     T = ((T >> 1) & 0xFFFF0000) | (in & 0xFFFF);  in arm_radix2_butterfly_inverse_q15()
461     R = __QSUB16(T, S);  in arm_radix2_butterfly_inverse_q15()
463     write_q15x2 (pSrc + (2 * i), __SHADD16(T, S));  in arm_radix2_butterfly_inverse_q15()
498         T = read_q15x2 (pSrc + (2 * i));  in arm_radix2_butterfly_inverse_q15()
502         R = __QSUB16(T, S);  in arm_radix2_butterfly_inverse_q15()
504         write_q15x2 (pSrc + (2 * i), __SHADD16(T, S));  in arm_radix2_butterfly_inverse_q15()
520         T = read_q15x2 (pSrc + (2 * i));  in arm_radix2_butterfly_inverse_q15()
524         R = __QSUB16(T, S);  in arm_radix2_butterfly_inverse_q15()
526         write_q15x2 (pSrc + (2 * i), __SHADD16(T, S));  in arm_radix2_butterfly_inverse_q15()
561       T = read_q15x2 (pSrc + (2 * i));  in arm_radix2_butterfly_inverse_q15()
565       R = __QSUB16(T, S);  in arm_radix2_butterfly_inverse_q15()
567       write_q15x2 (pSrc + (2 * i), __QADD16(T, S));  in arm_radix2_butterfly_inverse_q15()
601       xt = (pSrc[2 * i] >> 1U) - (pSrc[2 * l] >> 1U);  in arm_radix2_butterfly_inverse_q15()
604       yt = (pSrc[2 * i + 1] >> 1U) - (pSrc[2 * l + 1] >> 1U);  in arm_radix2_butterfly_inverse_q15()
608       pSrc[2 * l] = (((int16_t) (((q31_t) xt * cosVal) >> 16)) -  in arm_radix2_butterfly_inverse_q15()
638         xt = pSrc[2 * i] - pSrc[2 * l];  in arm_radix2_butterfly_inverse_q15()
641         yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];  in arm_radix2_butterfly_inverse_q15()
644         pSrc[2 * l] = (((int16_t) (((q31_t) xt * cosVal) >> 16)) -  in arm_radix2_butterfly_inverse_q15()
670     xt = pSrc[2 * i] - pSrc[2 * l];  in arm_radix2_butterfly_inverse_q15()
673     yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];  in arm_radix2_butterfly_inverse_q15()