/* ----------------------------------------------------------------------
* 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;
}
}