--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.6pre17/src/spandsp/fir.h	Fri Jun 25 15:50:58 2010 +0200
@@ -0,0 +1,304 @@
+/*
+ * 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.
+ *
+ * $Id: fir.h,v 1.13 2008/04/17 14:27:00 steveu Exp $
+ */
+
+/*! \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 ------------------------------------------------------------*/