/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_cfft_radix2_q15.c
* Description: Radix-2 Decimation in Frequency CFFT & CIFFT Fixed point processing function
*
* $Date: 18. March 2019
* $Revision: V1.6.0
*
* Target Processor: Cortex-M cores
* -------------------------------------------------------------------- */
/*
* Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the License); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an AS IS BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "arm_math.h"
void arm_radix2_butterfly_q15(
q15_t * pSrc,
uint32_t fftLen,
const q15_t * pCoef,
uint16_t twidCoefModifier);
void arm_radix2_butterfly_inverse_q15(
q15_t * pSrc,
uint32_t fftLen,
const q15_t * pCoef,
uint16_t twidCoefModifier);
void arm_bitreversal_q15(
q15_t * pSrc,
uint32_t fftLen,
uint16_t bitRevFactor,
const uint16_t * pBitRevTab);
/**
@ingroup groupTransforms
*/
/**
@addtogroup ComplexFFT
@{
*/
/**
@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 It has been superseded by \ref arm_cfft_q15 and will be removed in the future.
@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,
const q15_t * pCoef,
uint16_t twidCoefModifier)
{
#if defined (ARM_MATH_DSP)
uint32_t i, j, k, l;
uint32_t 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 = read_q15x2 ((q15_t *)pCoef + (ia * 2U));
ia = ia + twidCoefModifier;
l = i + n2;
T = read_q15x2 (pSrc + (2 * i));
in = ((int16_t) (T & 0xFFFF)) >> 1;
T = ((T >> 1) & 0xFFFF0000) | (in & 0xFFFF);
S = read_q15x2 (pSrc + (2 * l));
in = ((int16_t) (S & 0xFFFF)) >> 1;
S = ((S >> 1) & 0xFFFF0000) | (in & 0xFFFF);
R = __QSUB16(T, S);
write_q15x2 (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 */
write_q15x2 (pSrc + (2U * l), (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF));
coeff = read_q15x2 ((q15_t *)pCoef + (ia * 2U));
ia = ia + twidCoefModifier;
/* loop for butterfly */
i++;
l++;
T = read_q15x2 (pSrc + (2 * i));
in = ((int16_t) (T & 0xFFFF)) >> 1;
T = ((T >> 1) & 0xFFFF0000) | (in & 0xFFFF);
S = read_q15x2 (pSrc + (2 * l));
in = ((int16_t) (S & 0xFFFF)) >> 1;
S = ((S >> 1) & 0xFFFF0000) | (in & 0xFFFF);
R = __QSUB16(T, S);
write_q15x2 (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 */
write_q15x2 (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 = read_q15x2 ((q15_t *)pCoef + (ia * 2U));
ia = ia + twidCoefModifier;
/* loop for butterfly */
for (i = j; i < fftLen; i += n1)
{
l = i + n2;
T = read_q15x2 (pSrc + (2 * i));
S = read_q15x2 (pSrc + (2 * l));
R = __QSUB16(T, S);
write_q15x2 (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 */
write_q15x2 (pSrc + (2U * l), (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF));
i += n1;
l = i + n2;
T = read_q15x2 (pSrc + (2 * i));
S = read_q15x2 (pSrc + (2 * l));
R = __QSUB16(T, S);
write_q15x2 (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 */
write_q15x2 (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 = read_q15x2 ((q15_t *)pCoef + (ia * 2U));
ia = ia + twidCoefModifier;
/* loop for butterfly */
for (i = 0; i < fftLen; i += n1)
{
l = i + n2;
T = read_q15x2 (pSrc + (2 * i));
S = read_q15x2 (pSrc + (2 * l));
R = __QSUB16(T, S);
write_q15x2 (pSrc + (2 * i), __QADD16(T, S));
write_q15x2 (pSrc + (2 * l), R);
i += n1;
l = i + n2;
T = read_q15x2 (pSrc + (2 * i));
S = read_q15x2 (pSrc + (2 * l));
R = __QSUB16(T, S);
write_q15x2 (pSrc + (2 * i), __QADD16(T, S));
write_q15x2 (pSrc + (2 * l), R);
} /* groups loop end */
#else /* #if defined (ARM_MATH_DSP) */
uint32_t i, j, k, l;
uint32_t 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[2 * l] = (((int16_t) (((q31_t) xt * cosVal) >> 16)) +
((int16_t) (((q31_t) yt * sinVal) >> 16)));
pSrc[2U * l + 1] = (((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[2 * l] = (((int16_t) (((q31_t) xt * cosVal) >> 16)) +
((int16_t) (((q31_t) yt * sinVal) >> 16)));
pSrc[2U * l + 1] = (((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[2 * l] = xt;
pSrc[2 * l + 1] = yt;
} /* butterfly loop end */
} /* groups loop end */
twidCoefModifier = twidCoefModifier << 1U;
#endif /* #if defined (ARM_MATH_DSP) */
}
void arm_radix2_butterfly_inverse_q15(
q15_t * pSrc,
uint32_t fftLen,
const q15_t * pCoef,
uint16_t twidCoefModifier)
{
#if defined (ARM_MATH_DSP)
uint32_t i, j, k, l;
uint32_t 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 = read_q15x2 ((q15_t *)pCoef + (ia * 2U));
ia = ia + twidCoefModifier;
l = i + n2;
T = read_q15x2 (pSrc + (2 * i));
in = ((int16_t) (T & 0xFFFF)) >> 1;
T = ((T >> 1) & 0xFFFF0000) | (in & 0xFFFF);
S = read_q15x2 (pSrc + (2 * l));
in = ((int16_t) (S & 0xFFFF)) >> 1;
S = ((S >> 1) & 0xFFFF0000) | (in & 0xFFFF);
R = __QSUB16(T, S);
write_q15x2 (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 */
write_q15x2 (pSrc + (2 * l), (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF));
coeff = read_q15x2 ((q15_t *)pCoef + (ia * 2U));
ia = ia + twidCoefModifier;
/* loop for butterfly */
i++;
l++;
T = read_q15x2 (pSrc + (2 * i));
in = ((int16_t) (T & 0xFFFF)) >> 1;
T = ((T >> 1) & 0xFFFF0000) | (in & 0xFFFF);
S = read_q15x2 (pSrc + (2 * l));
in = ((int16_t) (S & 0xFFFF)) >> 1;
S = ((S >> 1) & 0xFFFF0000) | (in & 0xFFFF);
R = __QSUB16(T, S);
write_q15x2 (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 */
write_q15x2 (pSrc + (2 * 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 = read_q15x2 ((q15_t *)pCoef + (ia * 2U));
ia = ia + twidCoefModifier;
/* loop for butterfly */
for (i = j; i < fftLen; i += n1)
{
l = i + n2;
T = read_q15x2 (pSrc + (2 * i));
S = read_q15x2 (pSrc + (2 * l));
R = __QSUB16(T, S);
write_q15x2 (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 */
write_q15x2 (pSrc + (2 * l), (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF));
i += n1;
l = i + n2;
T = read_q15x2 (pSrc + (2 * i));
S = read_q15x2 (pSrc + (2 * l));
R = __QSUB16(T, S);
write_q15x2 (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 */
write_q15x2 (pSrc + (2 * 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 = read_q15x2 ((q15_t *)pCoef + (ia * 2U));
ia = ia + twidCoefModifier;
/* loop for butterfly */
for (i = j; i < fftLen; i += n1)
{
l = i + n2;
T = read_q15x2 (pSrc + (2 * i));
S = read_q15x2 (pSrc + (2 * l));
R = __QSUB16(T, S);
write_q15x2 (pSrc + (2 * i), __QADD16(T, S));
write_q15x2 (pSrc + (2 * l), R);
} /* butterfly loop end */
} /* groups loop end */
twidCoefModifier = twidCoefModifier << 1U;
#else /* #if defined (ARM_MATH_DSP) */
uint32_t i, j, k, l;
uint32_t 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[2 * l] = (((int16_t) (((q31_t) xt * cosVal) >> 16)) -
((int16_t) (((q31_t) yt * sinVal) >> 16)));
pSrc[2 * l + 1] = (((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[2 * l] = (((int16_t) (((q31_t) xt * cosVal) >> 16)) -
((int16_t) (((q31_t) yt * sinVal) >> 16)) );
pSrc[2 * l + 1] = (((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[2 * l] = xt;
pSrc[2 * l + 1] = yt;
} /* groups loop end */
#endif /* #if defined (ARM_MATH_DSP) */
}
