| /* ---------------------------------------------------------------------- |
| * 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_radix2_q15.c |
| * |
| * Description: Radix-2 Decimation in Frequency CFFT & CIFFT 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" |
| |
| void arm_radix2_butterfly_q15( |
| q15_t * pSrc, |
| uint32_t fftLen, |
| q15_t * pCoef, |
| uint16_t twidCoefModifier); |
| |
| void arm_radix2_butterfly_inverse_q15( |
| q15_t * pSrc, |
| uint32_t fftLen, |
| q15_t * pCoef, |
| uint16_t twidCoefModifier); |
| |
| void arm_bitreversal_q15( |
| q15_t * pSrc, |
| uint32_t fftLen, |
| uint16_t bitRevFactor, |
| uint16_t * pBitRevTab); |
| |
| /** |
| * @ingroup groupTransforms |
| */ |
| |
| /** |
| * @addtogroup ComplexFFT |
| * @{ |
| */ |
| |
| /** |
| * @details |
| * @brief Processing function for the fixed-point CFFT/CIFFT. |
| * @deprecated Do not use this function. It has been superseded by \ref arm_cfft_q15 and will be removed |
| * @param[in] *S points to an instance of the fixed-point CFFT/CIFFT structure. |
| * @param[in, out] *pSrc points to the complex data buffer of size <code>2*fftLen</code>. Processing occurs in-place. |
| * @return none. |
| */ |
| |
| void arm_cfft_radix2_q15( |
| const arm_cfft_radix2_instance_q15 * S, |
| q15_t * pSrc) |
| { |
| |
| if(S->ifftFlag == 1u) |
| { |
| arm_radix2_butterfly_inverse_q15(pSrc, S->fftLen, |
| S->pTwiddle, S->twidCoefModifier); |
| } |
| else |
| { |
| arm_radix2_butterfly_q15(pSrc, S->fftLen, |
| S->pTwiddle, S->twidCoefModifier); |
| } |
| |
| arm_bitreversal_q15(pSrc, S->fftLen, S->bitRevFactor, S->pBitRevTable); |
| } |
| |
| /** |
| * @} end of ComplexFFT group |
| */ |
| |
| void arm_radix2_butterfly_q15( |
| q15_t * pSrc, |
| uint32_t fftLen, |
| q15_t * pCoef, |
| uint16_t twidCoefModifier) |
| { |
| #ifndef ARM_MATH_CM0_FAMILY |
| |
| unsigned i, j, k, l; |
| unsigned n1, n2, ia; |
| q15_t in; |
| q31_t T, S, R; |
| q31_t coeff, out1, out2; |
| |
| //N = fftLen; |
| n2 = fftLen; |
| |
| n1 = n2; |
| n2 = n2 >> 1; |
| ia = 0; |
| |
| // loop for groups |
| for (i = 0; i < n2; i++) |
| { |
| coeff = _SIMD32_OFFSET(pCoef + (ia * 2u)); |
| |
| ia = ia + twidCoefModifier; |
| |
| l = i + n2; |
| |
| T = _SIMD32_OFFSET(pSrc + (2 * i)); |
| in = ((int16_t) (T & 0xFFFF)) >> 1; |
| T = ((T >> 1) & 0xFFFF0000) | (in & 0xFFFF); |
| |
| S = _SIMD32_OFFSET(pSrc + (2 * l)); |
| in = ((int16_t) (S & 0xFFFF)) >> 1; |
| S = ((S >> 1) & 0xFFFF0000) | (in & 0xFFFF); |
| |
| R = __QSUB16(T, S); |
| |
| _SIMD32_OFFSET(pSrc + (2 * i)) = __SHADD16(T, S); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| out1 = __SMUAD(coeff, R) >> 16; |
| out2 = __SMUSDX(coeff, R); |
| |
| #else |
| |
| out1 = __SMUSDX(R, coeff) >> 16u; |
| out2 = __SMUAD(coeff, R); |
| |
| #endif // #ifndef ARM_MATH_BIG_ENDIAN |
| |
| _SIMD32_OFFSET(pSrc + (2u * l)) = |
| (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
| |
| coeff = _SIMD32_OFFSET(pCoef + (ia * 2u)); |
| |
| ia = ia + twidCoefModifier; |
| |
| // loop for butterfly |
| i++; |
| l++; |
| |
| T = _SIMD32_OFFSET(pSrc + (2 * i)); |
| in = ((int16_t) (T & 0xFFFF)) >> 1; |
| T = ((T >> 1) & 0xFFFF0000) | (in & 0xFFFF); |
| |
| S = _SIMD32_OFFSET(pSrc + (2 * l)); |
| in = ((int16_t) (S & 0xFFFF)) >> 1; |
| S = ((S >> 1) & 0xFFFF0000) | (in & 0xFFFF); |
| |
| R = __QSUB16(T, S); |
| |
| _SIMD32_OFFSET(pSrc + (2 * i)) = __SHADD16(T, S); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| out1 = __SMUAD(coeff, R) >> 16; |
| out2 = __SMUSDX(coeff, R); |
| |
| #else |
| |
| out1 = __SMUSDX(R, coeff) >> 16u; |
| out2 = __SMUAD(coeff, R); |
| |
| #endif // #ifndef ARM_MATH_BIG_ENDIAN |
| |
| _SIMD32_OFFSET(pSrc + (2u * l)) = |
| (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
| |
| } // groups loop end |
| |
| twidCoefModifier = twidCoefModifier << 1u; |
| |
| // loop for stage |
| for (k = fftLen / 2; k > 2; k = k >> 1) |
| { |
| n1 = n2; |
| n2 = n2 >> 1; |
| ia = 0; |
| |
| // loop for groups |
| for (j = 0; j < n2; j++) |
| { |
| coeff = _SIMD32_OFFSET(pCoef + (ia * 2u)); |
| |
| ia = ia + twidCoefModifier; |
| |
| // loop for butterfly |
| for (i = j; i < fftLen; i += n1) |
| { |
| l = i + n2; |
| |
| T = _SIMD32_OFFSET(pSrc + (2 * i)); |
| |
| S = _SIMD32_OFFSET(pSrc + (2 * l)); |
| |
| R = __QSUB16(T, S); |
| |
| _SIMD32_OFFSET(pSrc + (2 * i)) = __SHADD16(T, S); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| out1 = __SMUAD(coeff, R) >> 16; |
| out2 = __SMUSDX(coeff, R); |
| |
| #else |
| |
| out1 = __SMUSDX(R, coeff) >> 16u; |
| out2 = __SMUAD(coeff, R); |
| |
| #endif // #ifndef ARM_MATH_BIG_ENDIAN |
| |
| _SIMD32_OFFSET(pSrc + (2u * l)) = |
| (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
| |
| i += n1; |
| |
| l = i + n2; |
| |
| T = _SIMD32_OFFSET(pSrc + (2 * i)); |
| |
| S = _SIMD32_OFFSET(pSrc + (2 * l)); |
| |
| R = __QSUB16(T, S); |
| |
| _SIMD32_OFFSET(pSrc + (2 * i)) = __SHADD16(T, S); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| out1 = __SMUAD(coeff, R) >> 16; |
| out2 = __SMUSDX(coeff, R); |
| |
| #else |
| |
| out1 = __SMUSDX(R, coeff) >> 16u; |
| out2 = __SMUAD(coeff, R); |
| |
| #endif // #ifndef ARM_MATH_BIG_ENDIAN |
| |
| _SIMD32_OFFSET(pSrc + (2u * l)) = |
| (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
| |
| } // butterfly loop end |
| |
| } // groups loop end |
| |
| twidCoefModifier = twidCoefModifier << 1u; |
| } // stages loop end |
| |
| n1 = n2; |
| n2 = n2 >> 1; |
| ia = 0; |
| |
| coeff = _SIMD32_OFFSET(pCoef + (ia * 2u)); |
| |
| ia = ia + twidCoefModifier; |
| |
| // loop for butterfly |
| for (i = 0; i < fftLen; i += n1) |
| { |
| l = i + n2; |
| |
| T = _SIMD32_OFFSET(pSrc + (2 * i)); |
| |
| S = _SIMD32_OFFSET(pSrc + (2 * l)); |
| |
| R = __QSUB16(T, S); |
| |
| _SIMD32_OFFSET(pSrc + (2 * i)) = __QADD16(T, S); |
| |
| _SIMD32_OFFSET(pSrc + (2u * l)) = R; |
| |
| i += n1; |
| l = i + n2; |
| |
| T = _SIMD32_OFFSET(pSrc + (2 * i)); |
| |
| S = _SIMD32_OFFSET(pSrc + (2 * l)); |
| |
| R = __QSUB16(T, S); |
| |
| _SIMD32_OFFSET(pSrc + (2 * i)) = __QADD16(T, S); |
| |
| _SIMD32_OFFSET(pSrc + (2u * l)) = R; |
| |
| } // groups loop end |
| |
| |
| #else |
| |
| unsigned i, j, k, l; |
| unsigned n1, n2, ia; |
| q15_t xt, yt, cosVal, sinVal; |
| |
| |
| //N = fftLen; |
| n2 = fftLen; |
| |
| n1 = n2; |
| n2 = n2 >> 1; |
| ia = 0; |
| |
| // loop for groups |
| for (j = 0; j < n2; j++) |
| { |
| cosVal = pCoef[ia * 2]; |
| sinVal = pCoef[(ia * 2) + 1]; |
| ia = ia + twidCoefModifier; |
| |
| // loop for butterfly |
| for (i = j; i < fftLen; i += n1) |
| { |
| l = i + n2; |
| xt = (pSrc[2 * i] >> 1u) - (pSrc[2 * l] >> 1u); |
| pSrc[2 * i] = ((pSrc[2 * i] >> 1u) + (pSrc[2 * l] >> 1u)) >> 1u; |
| |
| yt = (pSrc[2 * i + 1] >> 1u) - (pSrc[2 * l + 1] >> 1u); |
| pSrc[2 * i + 1] = |
| ((pSrc[2 * l + 1] >> 1u) + (pSrc[2 * i + 1] >> 1u)) >> 1u; |
| |
| pSrc[2u * l] = (((int16_t) (((q31_t) xt * cosVal) >> 16)) + |
| ((int16_t) (((q31_t) yt * sinVal) >> 16))); |
| |
| pSrc[2u * l + 1u] = (((int16_t) (((q31_t) yt * cosVal) >> 16)) - |
| ((int16_t) (((q31_t) xt * sinVal) >> 16))); |
| |
| } // butterfly loop end |
| |
| } // groups loop end |
| |
| twidCoefModifier = twidCoefModifier << 1u; |
| |
| // loop for stage |
| for (k = fftLen / 2; k > 2; k = k >> 1) |
| { |
| n1 = n2; |
| n2 = n2 >> 1; |
| ia = 0; |
| |
| // loop for groups |
| for (j = 0; j < n2; j++) |
| { |
| cosVal = pCoef[ia * 2]; |
| sinVal = pCoef[(ia * 2) + 1]; |
| ia = ia + twidCoefModifier; |
| |
| // loop for butterfly |
| for (i = j; i < fftLen; i += n1) |
| { |
| l = i + n2; |
| xt = pSrc[2 * i] - pSrc[2 * l]; |
| pSrc[2 * i] = (pSrc[2 * i] + pSrc[2 * l]) >> 1u; |
| |
| yt = pSrc[2 * i + 1] - pSrc[2 * l + 1]; |
| pSrc[2 * i + 1] = (pSrc[2 * l + 1] + pSrc[2 * i + 1]) >> 1u; |
| |
| pSrc[2u * l] = (((int16_t) (((q31_t) xt * cosVal) >> 16)) + |
| ((int16_t) (((q31_t) yt * sinVal) >> 16))); |
| |
| pSrc[2u * l + 1u] = (((int16_t) (((q31_t) yt * cosVal) >> 16)) - |
| ((int16_t) (((q31_t) xt * sinVal) >> 16))); |
| |
| } // butterfly loop end |
| |
| } // groups loop end |
| |
| twidCoefModifier = twidCoefModifier << 1u; |
| } // stages loop end |
| |
| n1 = n2; |
| n2 = n2 >> 1; |
| ia = 0; |
| |
| // loop for groups |
| for (j = 0; j < n2; j++) |
| { |
| cosVal = pCoef[ia * 2]; |
| sinVal = pCoef[(ia * 2) + 1]; |
| |
| ia = ia + twidCoefModifier; |
| |
| // loop for butterfly |
| for (i = j; i < fftLen; i += n1) |
| { |
| l = i + n2; |
| xt = pSrc[2 * i] - pSrc[2 * l]; |
| pSrc[2 * i] = (pSrc[2 * i] + pSrc[2 * l]); |
| |
| yt = pSrc[2 * i + 1] - pSrc[2 * l + 1]; |
| pSrc[2 * i + 1] = (pSrc[2 * l + 1] + pSrc[2 * i + 1]); |
| |
| pSrc[2u * l] = xt; |
| |
| pSrc[2u * l + 1u] = yt; |
| |
| } // butterfly loop end |
| |
| } // groups loop end |
| |
| twidCoefModifier = twidCoefModifier << 1u; |
| |
| #endif // #ifndef ARM_MATH_CM0_FAMILY |
| |
| } |
| |
| |
| void arm_radix2_butterfly_inverse_q15( |
| q15_t * pSrc, |
| uint32_t fftLen, |
| q15_t * pCoef, |
| uint16_t twidCoefModifier) |
| { |
| #ifndef ARM_MATH_CM0_FAMILY |
| |
| unsigned i, j, k, l; |
| unsigned n1, n2, ia; |
| q15_t in; |
| q31_t T, S, R; |
| q31_t coeff, out1, out2; |
| |
| //N = fftLen; |
| n2 = fftLen; |
| |
| n1 = n2; |
| n2 = n2 >> 1; |
| ia = 0; |
| |
| // loop for groups |
| for (i = 0; i < n2; i++) |
| { |
| coeff = _SIMD32_OFFSET(pCoef + (ia * 2u)); |
| |
| ia = ia + twidCoefModifier; |
| |
| l = i + n2; |
| |
| T = _SIMD32_OFFSET(pSrc + (2 * i)); |
| in = ((int16_t) (T & 0xFFFF)) >> 1; |
| T = ((T >> 1) & 0xFFFF0000) | (in & 0xFFFF); |
| |
| S = _SIMD32_OFFSET(pSrc + (2 * l)); |
| in = ((int16_t) (S & 0xFFFF)) >> 1; |
| S = ((S >> 1) & 0xFFFF0000) | (in & 0xFFFF); |
| |
| R = __QSUB16(T, S); |
| |
| _SIMD32_OFFSET(pSrc + (2 * i)) = __SHADD16(T, S); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| out1 = __SMUSD(coeff, R) >> 16; |
| out2 = __SMUADX(coeff, R); |
| #else |
| |
| out1 = __SMUADX(R, coeff) >> 16u; |
| out2 = __SMUSD(__QSUB(0, coeff), R); |
| |
| #endif // #ifndef ARM_MATH_BIG_ENDIAN |
| |
| _SIMD32_OFFSET(pSrc + (2u * l)) = |
| (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
| |
| coeff = _SIMD32_OFFSET(pCoef + (ia * 2u)); |
| |
| ia = ia + twidCoefModifier; |
| |
| // loop for butterfly |
| i++; |
| l++; |
| |
| T = _SIMD32_OFFSET(pSrc + (2 * i)); |
| in = ((int16_t) (T & 0xFFFF)) >> 1; |
| T = ((T >> 1) & 0xFFFF0000) | (in & 0xFFFF); |
| |
| S = _SIMD32_OFFSET(pSrc + (2 * l)); |
| in = ((int16_t) (S & 0xFFFF)) >> 1; |
| S = ((S >> 1) & 0xFFFF0000) | (in & 0xFFFF); |
| |
| R = __QSUB16(T, S); |
| |
| _SIMD32_OFFSET(pSrc + (2 * i)) = __SHADD16(T, S); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| out1 = __SMUSD(coeff, R) >> 16; |
| out2 = __SMUADX(coeff, R); |
| #else |
| |
| out1 = __SMUADX(R, coeff) >> 16u; |
| out2 = __SMUSD(__QSUB(0, coeff), R); |
| |
| #endif // #ifndef ARM_MATH_BIG_ENDIAN |
| |
| _SIMD32_OFFSET(pSrc + (2u * l)) = |
| (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
| |
| } // groups loop end |
| |
| twidCoefModifier = twidCoefModifier << 1u; |
| |
| // loop for stage |
| for (k = fftLen / 2; k > 2; k = k >> 1) |
| { |
| n1 = n2; |
| n2 = n2 >> 1; |
| ia = 0; |
| |
| // loop for groups |
| for (j = 0; j < n2; j++) |
| { |
| coeff = _SIMD32_OFFSET(pCoef + (ia * 2u)); |
| |
| ia = ia + twidCoefModifier; |
| |
| // loop for butterfly |
| for (i = j; i < fftLen; i += n1) |
| { |
| l = i + n2; |
| |
| T = _SIMD32_OFFSET(pSrc + (2 * i)); |
| |
| S = _SIMD32_OFFSET(pSrc + (2 * l)); |
| |
| R = __QSUB16(T, S); |
| |
| _SIMD32_OFFSET(pSrc + (2 * i)) = __SHADD16(T, S); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| out1 = __SMUSD(coeff, R) >> 16; |
| out2 = __SMUADX(coeff, R); |
| |
| #else |
| |
| out1 = __SMUADX(R, coeff) >> 16u; |
| out2 = __SMUSD(__QSUB(0, coeff), R); |
| |
| #endif // #ifndef ARM_MATH_BIG_ENDIAN |
| |
| _SIMD32_OFFSET(pSrc + (2u * l)) = |
| (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
| |
| i += n1; |
| |
| l = i + n2; |
| |
| T = _SIMD32_OFFSET(pSrc + (2 * i)); |
| |
| S = _SIMD32_OFFSET(pSrc + (2 * l)); |
| |
| R = __QSUB16(T, S); |
| |
| _SIMD32_OFFSET(pSrc + (2 * i)) = __SHADD16(T, S); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| out1 = __SMUSD(coeff, R) >> 16; |
| out2 = __SMUADX(coeff, R); |
| #else |
| |
| out1 = __SMUADX(R, coeff) >> 16u; |
| out2 = __SMUSD(__QSUB(0, coeff), R); |
| |
| #endif // #ifndef ARM_MATH_BIG_ENDIAN |
| |
| _SIMD32_OFFSET(pSrc + (2u * l)) = |
| (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
| |
| } // butterfly loop end |
| |
| } // groups loop end |
| |
| twidCoefModifier = twidCoefModifier << 1u; |
| } // stages loop end |
| |
| n1 = n2; |
| n2 = n2 >> 1; |
| ia = 0; |
| |
| // loop for groups |
| for (j = 0; j < n2; j++) |
| { |
| coeff = _SIMD32_OFFSET(pCoef + (ia * 2u)); |
| |
| ia = ia + twidCoefModifier; |
| |
| // loop for butterfly |
| for (i = j; i < fftLen; i += n1) |
| { |
| l = i + n2; |
| |
| T = _SIMD32_OFFSET(pSrc + (2 * i)); |
| |
| S = _SIMD32_OFFSET(pSrc + (2 * l)); |
| |
| R = __QSUB16(T, S); |
| |
| _SIMD32_OFFSET(pSrc + (2 * i)) = __QADD16(T, S); |
| |
| _SIMD32_OFFSET(pSrc + (2u * l)) = R; |
| |
| } // butterfly loop end |
| |
| } // groups loop end |
| |
| twidCoefModifier = twidCoefModifier << 1u; |
| |
| #else |
| |
| |
| unsigned i, j, k, l; |
| unsigned n1, n2, ia; |
| q15_t xt, yt, cosVal, sinVal; |
| |
| //N = fftLen; |
| n2 = fftLen; |
| |
| n1 = n2; |
| n2 = n2 >> 1; |
| ia = 0; |
| |
| // loop for groups |
| for (j = 0; j < n2; j++) |
| { |
| cosVal = pCoef[ia * 2]; |
| sinVal = pCoef[(ia * 2) + 1]; |
| ia = ia + twidCoefModifier; |
| |
| // loop for butterfly |
| for (i = j; i < fftLen; i += n1) |
| { |
| l = i + n2; |
| xt = (pSrc[2 * i] >> 1u) - (pSrc[2 * l] >> 1u); |
| pSrc[2 * i] = ((pSrc[2 * i] >> 1u) + (pSrc[2 * l] >> 1u)) >> 1u; |
| |
| yt = (pSrc[2 * i + 1] >> 1u) - (pSrc[2 * l + 1] >> 1u); |
| pSrc[2 * i + 1] = |
| ((pSrc[2 * l + 1] >> 1u) + (pSrc[2 * i + 1] >> 1u)) >> 1u; |
| |
| pSrc[2u * l] = (((int16_t) (((q31_t) xt * cosVal) >> 16)) - |
| ((int16_t) (((q31_t) yt * sinVal) >> 16))); |
| |
| pSrc[2u * l + 1u] = (((int16_t) (((q31_t) yt * cosVal) >> 16)) + |
| ((int16_t) (((q31_t) xt * sinVal) >> 16))); |
| |
| } // butterfly loop end |
| |
| } // groups loop end |
| |
| twidCoefModifier = twidCoefModifier << 1u; |
| |
| // loop for stage |
| for (k = fftLen / 2; k > 2; k = k >> 1) |
| { |
| n1 = n2; |
| n2 = n2 >> 1; |
| ia = 0; |
| |
| // loop for groups |
| for (j = 0; j < n2; j++) |
| { |
| cosVal = pCoef[ia * 2]; |
| sinVal = pCoef[(ia * 2) + 1]; |
| ia = ia + twidCoefModifier; |
| |
| // loop for butterfly |
| for (i = j; i < fftLen; i += n1) |
| { |
| l = i + n2; |
| xt = pSrc[2 * i] - pSrc[2 * l]; |
| pSrc[2 * i] = (pSrc[2 * i] + pSrc[2 * l]) >> 1u; |
| |
| yt = pSrc[2 * i + 1] - pSrc[2 * l + 1]; |
| pSrc[2 * i + 1] = (pSrc[2 * l + 1] + pSrc[2 * i + 1]) >> 1u; |
| |
| pSrc[2u * l] = (((int16_t) (((q31_t) xt * cosVal) >> 16)) - |
| ((int16_t) (((q31_t) yt * sinVal) >> 16))); |
| |
| pSrc[2u * l + 1u] = (((int16_t) (((q31_t) yt * cosVal) >> 16)) + |
| ((int16_t) (((q31_t) xt * sinVal) >> 16))); |
| |
| } // butterfly loop end |
| |
| } // groups loop end |
| |
| twidCoefModifier = twidCoefModifier << 1u; |
| } // stages loop end |
| |
| n1 = n2; |
| n2 = n2 >> 1; |
| ia = 0; |
| |
| cosVal = pCoef[ia * 2]; |
| sinVal = pCoef[(ia * 2) + 1]; |
| |
| ia = ia + twidCoefModifier; |
| |
| // loop for butterfly |
| for (i = 0; i < fftLen; i += n1) |
| { |
| l = i + n2; |
| xt = pSrc[2 * i] - pSrc[2 * l]; |
| pSrc[2 * i] = (pSrc[2 * i] + pSrc[2 * l]); |
| |
| yt = pSrc[2 * i + 1] - pSrc[2 * l + 1]; |
| pSrc[2 * i + 1] = (pSrc[2 * l + 1] + pSrc[2 * i + 1]); |
| |
| pSrc[2u * l] = xt; |
| |
| pSrc[2u * l + 1u] = yt; |
| |
| } // groups loop end |
| |
| |
| #endif // #ifndef ARM_MATH_CM0_FAMILY |
| |
| } |
