| /* ---------------------------------------------------------------------- |
| * Copyright (C) 2010-2014 ARM Limited. All rights reserved. |
| * |
| * $Date: 19. March 2015 |
| * $Revision: V.1.4.5 |
| * |
| * Project: CMSIS DSP Library |
| * Title: arm_cfft_q31.c |
| * |
| * Description: Combined Radix Decimation in Frequency CFFT fixed point processing function |
| * |
| * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * - Neither the name of ARM LIMITED nor the names of its contributors |
| * may be used to endorse or promote products derived from this |
| * software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
| * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
| * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
| * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| * POSSIBILITY OF SUCH DAMAGE. |
| * -------------------------------------------------------------------- */ |
| |
| #include "arm_math.h" |
| |
| extern void arm_radix4_butterfly_q31( |
| q31_t * pSrc, |
| uint32_t fftLen, |
| q31_t * pCoef, |
| uint32_t twidCoefModifier); |
| |
| extern void arm_radix4_butterfly_inverse_q31( |
| q31_t * pSrc, |
| uint32_t fftLen, |
| q31_t * pCoef, |
| uint32_t twidCoefModifier); |
| |
| extern void arm_bitreversal_32( |
| uint32_t * pSrc, |
| const uint16_t bitRevLen, |
| const uint16_t * pBitRevTable); |
| |
| void arm_cfft_radix4by2_q31( |
| q31_t * pSrc, |
| uint32_t fftLen, |
| const q31_t * pCoef); |
| |
| void arm_cfft_radix4by2_inverse_q31( |
| q31_t * pSrc, |
| uint32_t fftLen, |
| const q31_t * pCoef); |
| |
| /** |
| * @ingroup groupTransforms |
| */ |
| |
| /** |
| * @addtogroup ComplexFFT |
| * @{ |
| */ |
| |
| /** |
| * @details |
| * @brief Processing function for the fixed-point complex FFT in Q31 format. |
| * @param[in] *S points to an instance of the fixed-point CFFT structure. |
| * @param[in, out] *p1 points to the complex data buffer of size <code>2*fftLen</code>. Processing occurs in-place. |
| * @param[in] ifftFlag flag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform. |
| * @param[in] bitReverseFlag flag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output. |
| * @return none. |
| */ |
| |
| void arm_cfft_q31( |
| const arm_cfft_instance_q31 * S, |
| q31_t * p1, |
| uint8_t ifftFlag, |
| uint8_t bitReverseFlag) |
| { |
| uint32_t L = S->fftLen; |
| |
| if(ifftFlag == 1u) |
| { |
| switch (L) |
| { |
| case 16: |
| case 64: |
| case 256: |
| case 1024: |
| case 4096: |
| arm_radix4_butterfly_inverse_q31 ( p1, L, (q31_t*)S->pTwiddle, 1 ); |
| break; |
| |
| case 32: |
| case 128: |
| case 512: |
| case 2048: |
| arm_cfft_radix4by2_inverse_q31 ( p1, L, S->pTwiddle ); |
| break; |
| } |
| } |
| else |
| { |
| switch (L) |
| { |
| case 16: |
| case 64: |
| case 256: |
| case 1024: |
| case 4096: |
| arm_radix4_butterfly_q31 ( p1, L, (q31_t*)S->pTwiddle, 1 ); |
| break; |
| |
| case 32: |
| case 128: |
| case 512: |
| case 2048: |
| arm_cfft_radix4by2_q31 ( p1, L, S->pTwiddle ); |
| break; |
| } |
| } |
| |
| if( bitReverseFlag ) |
| arm_bitreversal_32((uint32_t*)p1,S->bitRevLength,S->pBitRevTable); |
| } |
| |
| /** |
| * @} end of ComplexFFT group |
| */ |
| |
| void arm_cfft_radix4by2_q31( |
| q31_t * pSrc, |
| uint32_t fftLen, |
| const q31_t * pCoef) |
| { |
| uint32_t i, l; |
| uint32_t n2, ia; |
| q31_t xt, yt, cosVal, sinVal; |
| q31_t p0, p1; |
| |
| n2 = fftLen >> 1; |
| ia = 0; |
| for (i = 0; i < n2; i++) |
| { |
| cosVal = pCoef[2*ia]; |
| sinVal = pCoef[2*ia + 1]; |
| ia++; |
| |
| l = i + n2; |
| xt = (pSrc[2 * i] >> 2) - (pSrc[2 * l] >> 2); |
| pSrc[2 * i] = (pSrc[2 * i] >> 2) + (pSrc[2 * l] >> 2); |
| |
| yt = (pSrc[2 * i + 1] >> 2) - (pSrc[2 * l + 1] >> 2); |
| pSrc[2 * i + 1] = (pSrc[2 * l + 1] >> 2) + (pSrc[2 * i + 1] >> 2); |
| |
| mult_32x32_keep32_R(p0, xt, cosVal); |
| mult_32x32_keep32_R(p1, yt, cosVal); |
| multAcc_32x32_keep32_R(p0, yt, sinVal); |
| multSub_32x32_keep32_R(p1, xt, sinVal); |
| |
| pSrc[2u * l] = p0 << 1; |
| pSrc[2u * l + 1u] = p1 << 1; |
| |
| } |
| |
| // first col |
| arm_radix4_butterfly_q31( pSrc, n2, (q31_t*)pCoef, 2u); |
| // second col |
| arm_radix4_butterfly_q31( pSrc + fftLen, n2, (q31_t*)pCoef, 2u); |
| |
| for (i = 0; i < fftLen >> 1; i++) |
| { |
| p0 = pSrc[4*i+0]; |
| p1 = pSrc[4*i+1]; |
| xt = pSrc[4*i+2]; |
| yt = pSrc[4*i+3]; |
| |
| p0 <<= 1; |
| p1 <<= 1; |
| xt <<= 1; |
| yt <<= 1; |
| |
| pSrc[4*i+0] = p0; |
| pSrc[4*i+1] = p1; |
| pSrc[4*i+2] = xt; |
| pSrc[4*i+3] = yt; |
| } |
| |
| } |
| |
| void arm_cfft_radix4by2_inverse_q31( |
| q31_t * pSrc, |
| uint32_t fftLen, |
| const q31_t * pCoef) |
| { |
| uint32_t i, l; |
| uint32_t n2, ia; |
| q31_t xt, yt, cosVal, sinVal; |
| q31_t p0, p1; |
| |
| n2 = fftLen >> 1; |
| ia = 0; |
| for (i = 0; i < n2; i++) |
| { |
| cosVal = pCoef[2*ia]; |
| sinVal = pCoef[2*ia + 1]; |
| ia++; |
| |
| l = i + n2; |
| xt = (pSrc[2 * i] >> 2) - (pSrc[2 * l] >> 2); |
| pSrc[2 * i] = (pSrc[2 * i] >> 2) + (pSrc[2 * l] >> 2); |
| |
| yt = (pSrc[2 * i + 1] >> 2) - (pSrc[2 * l + 1] >> 2); |
| pSrc[2 * i + 1] = (pSrc[2 * l + 1] >> 2) + (pSrc[2 * i + 1] >> 2); |
| |
| mult_32x32_keep32_R(p0, xt, cosVal); |
| mult_32x32_keep32_R(p1, yt, cosVal); |
| multSub_32x32_keep32_R(p0, yt, sinVal); |
| multAcc_32x32_keep32_R(p1, xt, sinVal); |
| |
| pSrc[2u * l] = p0 << 1; |
| pSrc[2u * l + 1u] = p1 << 1; |
| |
| } |
| |
| // first col |
| arm_radix4_butterfly_inverse_q31( pSrc, n2, (q31_t*)pCoef, 2u); |
| // second col |
| arm_radix4_butterfly_inverse_q31( pSrc + fftLen, n2, (q31_t*)pCoef, 2u); |
| |
| for (i = 0; i < fftLen >> 1; i++) |
| { |
| p0 = pSrc[4*i+0]; |
| p1 = pSrc[4*i+1]; |
| xt = pSrc[4*i+2]; |
| yt = pSrc[4*i+3]; |
| |
| p0 <<= 1; |
| p1 <<= 1; |
| xt <<= 1; |
| yt <<= 1; |
| |
| pSrc[4*i+0] = p0; |
| pSrc[4*i+1] = p1; |
| pSrc[4*i+2] = xt; |
| pSrc[4*i+3] = yt; |
| } |
| } |
| |
