fir.h
/*
* SpanDSP - a series of DSP components for telephony
*
* fir.h - General telephony FIR routines
*
* Written by Steve Underwood <steveu@coppice.org>
*
* Copyright (C) 2002 Steve Underwood
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License version 2.1,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*! \page fir_page FIR filtering
\section fir_page_sec_1 What does it do?
???.
\section fir_page_sec_2 How does it work?
???.
*/
#if !defined(_SPANDSP_FIR_H_)
#define _SPANDSP_FIR_H_
#if defined(USE_MMX) || defined(USE_SSE2)
#include "mmx.h"
#endif
/*!
16 bit integer FIR descriptor. This defines the working state for a single
instance of an FIR filter using 16 bit integer coefficients.
*/
typedef struct
{
int taps;
int curr_pos;
const int16_t *coeffs;
int16_t *history;
} fir16_state_t;
/*!
32 bit integer FIR descriptor. This defines the working state for a single
instance of an FIR filter using 32 bit integer coefficients, and filtering
16 bit integer data.
*/
typedef struct
{
int taps;
int curr_pos;
const int32_t *coeffs;
int16_t *history;
} fir32_state_t;
/*!
Floating point FIR descriptor. This defines the working state for a single
instance of an FIR filter using floating point coefficients and data.
*/
typedef struct
{
int taps;
int curr_pos;
const float *coeffs;
float *history;
} fir_float_state_t;
#if defined(__cplusplus)
extern "C"
{
#endif
static __inline__ const int16_t *fir16_create(fir16_state_t *fir,
const int16_t *coeffs,
int taps)
{
fir->taps = taps;
fir->curr_pos = taps - 1;
fir->coeffs = coeffs;
#if defined(USE_MMX) || defined(USE_SSE2)
if ((fir->history = malloc(2*taps*sizeof(int16_t))))
memset(fir->history, 0, 2*taps*sizeof(int16_t));
#else
if ((fir->history = (int16_t *) malloc(taps*sizeof(int16_t))))
memset(fir->history, 0, taps*sizeof(int16_t));
#endif
return fir->history;
}
/*- End of function --------------------------------------------------------*/
static __inline__ void fir16_flush(fir16_state_t *fir)
{
#if defined(USE_MMX) || defined(USE_SSE2)
memset(fir->history, 0, 2*fir->taps*sizeof(int16_t));
#else
memset(fir->history, 0, fir->taps*sizeof(int16_t));
#endif
}
/*- End of function --------------------------------------------------------*/
static __inline__ void fir16_free(fir16_state_t *fir)
{
free(fir->history);
}
/*- End of function --------------------------------------------------------*/
static __inline__ int16_t fir16(fir16_state_t *fir, int16_t sample)
{
int i;
int32_t y;
#if defined(USE_MMX)
mmx_t *mmx_coeffs;
mmx_t *mmx_hist;
fir->history[fir->curr_pos] = sample;
fir->history[fir->curr_pos + fir->taps] = sample;
mmx_coeffs = (mmx_t *) fir->coeffs;
mmx_hist = (mmx_t *) &fir->history[fir->curr_pos];
i = fir->taps;
pxor_r2r(mm4, mm4);
/* 8 samples per iteration, so the filter must be a multiple of 8 long. */
while (i > 0)
{
movq_m2r(mmx_coeffs[0], mm0);
movq_m2r(mmx_coeffs[1], mm2);
movq_m2r(mmx_hist[0], mm1);
movq_m2r(mmx_hist[1], mm3);
mmx_coeffs += 2;
mmx_hist += 2;
pmaddwd_r2r(mm1, mm0);
pmaddwd_r2r(mm3, mm2);
paddd_r2r(mm0, mm4);
paddd_r2r(mm2, mm4);
i -= 8;
}
movq_r2r(mm4, mm0);
psrlq_i2r(32, mm0);
paddd_r2r(mm0, mm4);
movd_r2m(mm4, y);
emms();
#elif defined(USE_SSE2)
xmm_t *xmm_coeffs;
xmm_t *xmm_hist;
fir->history[fir->curr_pos] = sample;
fir->history[fir->curr_pos + fir->taps] = sample;
xmm_coeffs = (xmm_t *) fir->coeffs;
xmm_hist = (xmm_t *) &fir->history[fir->curr_pos];
i = fir->taps;
pxor_r2r(xmm4, xmm4);
/* 16 samples per iteration, so the filter must be a multiple of 16 long. */
while (i > 0)
{
movdqu_m2r(xmm_coeffs[0], xmm0);
movdqu_m2r(xmm_coeffs[1], xmm2);
movdqu_m2r(xmm_hist[0], xmm1);
movdqu_m2r(xmm_hist[1], xmm3);
xmm_coeffs += 2;
xmm_hist += 2;
pmaddwd_r2r(xmm1, xmm0);
pmaddwd_r2r(xmm3, xmm2);
paddd_r2r(xmm0, xmm4);
paddd_r2r(xmm2, xmm4);
i -= 16;
}
movdqa_r2r(xmm4, xmm0);
psrldq_i2r(8, xmm0);
paddd_r2r(xmm0, xmm4);
movdqa_r2r(xmm4, xmm0);
psrldq_i2r(4, xmm0);
paddd_r2r(xmm0, xmm4);
movd_r2m(xmm4, y);
#else
int offset1;
int offset2;
fir->history[fir->curr_pos] = sample;
offset2 = fir->curr_pos;
offset1 = fir->taps - offset2;
y = 0;
for (i = fir->taps - 1; i >= offset1; i--)
y += fir->coeffs[i]*fir->history[i - offset1];
for ( ; i >= 0; i--)
y += fir->coeffs[i]*fir->history[i + offset2];
#endif
if (fir->curr_pos <= 0)
fir->curr_pos = fir->taps;
fir->curr_pos--;
return (int16_t) (y >> 15);
}
/*- End of function --------------------------------------------------------*/
static __inline__ const int16_t *fir32_create(fir32_state_t *fir,
const int32_t *coeffs,
int taps)
{
fir->taps = taps;
fir->curr_pos = taps - 1;
fir->coeffs = coeffs;
fir->history = (int16_t *) malloc(taps*sizeof(int16_t));
if (fir->history)
memset(fir->history, '\0', taps*sizeof(int16_t));
return fir->history;
}
/*- End of function --------------------------------------------------------*/
static __inline__ void fir32_flush(fir32_state_t *fir)
{
memset(fir->history, 0, fir->taps*sizeof(int16_t));
}
/*- End of function --------------------------------------------------------*/
static __inline__ void fir32_free(fir32_state_t *fir)
{
free(fir->history);
}
/*- End of function --------------------------------------------------------*/
static __inline__ int16_t fir32(fir32_state_t *fir, int16_t sample)
{
int i;
int32_t y;
int offset1;
int offset2;
fir->history[fir->curr_pos] = sample;
offset2 = fir->curr_pos;
offset1 = fir->taps - offset2;
y = 0;
for (i = fir->taps - 1; i >= offset1; i--)
y += fir->coeffs[i]*fir->history[i - offset1];
for ( ; i >= 0; i--)
y += fir->coeffs[i]*fir->history[i + offset2];
if (fir->curr_pos <= 0)
fir->curr_pos = fir->taps;
fir->curr_pos--;
return (int16_t) (y >> 15);
}
/*- End of function --------------------------------------------------------*/
static __inline__ const float *fir_float_create(fir_float_state_t *fir,
const float *coeffs,
int taps)
{
fir->taps = taps;
fir->curr_pos = taps - 1;
fir->coeffs = coeffs;
fir->history = (float *) malloc(taps*sizeof(float));
if (fir->history)
memset(fir->history, '\0', taps*sizeof(float));
return fir->history;
}
/*- End of function --------------------------------------------------------*/
static __inline__ void fir_float_free(fir_float_state_t *fir)
{
free(fir->history);
}
/*- End of function --------------------------------------------------------*/
static __inline__ int16_t fir_float(fir_float_state_t *fir, int16_t sample)
{
int i;
float y;
int offset1;
int offset2;
fir->history[fir->curr_pos] = sample;
offset2 = fir->curr_pos;
offset1 = fir->taps - offset2;
y = 0;
for (i = fir->taps - 1; i >= offset1; i--)
y += fir->coeffs[i]*fir->history[i - offset1];
for ( ; i >= 0; i--)
y += fir->coeffs[i]*fir->history[i + offset2];
if (fir->curr_pos <= 0)
fir->curr_pos = fir->taps;
fir->curr_pos--;
return (int16_t) y;
}
/*- End of function --------------------------------------------------------*/
#if defined(__cplusplus)
}
#endif
#endif
/*- End of file ------------------------------------------------------------*/
fir16_state_t
Definition fir.h:46
fir32_state_t
Definition fir.h:59
fir_float_state_t
Definition fir.h:71