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-rw-r--r--drivers/staging/echo/fir.h369
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+/*
+ * 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 General Public License version 2, 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU 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 1.8 2006/10/24 13:45:28 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(_FIR_H_)
+#define _FIR_H_
+
+/*
+ Blackfin NOTES & IDEAS:
+
+ A simple dot product function is used to implement the filter. This performs
+ just one MAC/cycle which is inefficient but was easy to implement as a first
+ pass. The current Blackfin code also uses an unrolled form of the filter
+ history to avoid 0 length hardware loop issues. This is wasteful of
+ memory.
+
+ Ideas for improvement:
+
+ 1/ Rewrite filter for dual MAC inner loop. The issue here is handling
+ history sample offsets that are 16 bit aligned - the dual MAC needs
+ 32 bit aligmnent. There are some good examples in libbfdsp.
+
+ 2/ Use the hardware circular buffer facility tohalve memory usage.
+
+ 3/ Consider using internal memory.
+
+ Using less memory might also improve speed as cache misses will be
+ reduced. A drop in MIPs and memory approaching 50% should be
+ possible.
+
+ The foreground and background filters currenlty use a total of
+ about 10 MIPs/ch as measured with speedtest.c on a 256 TAP echo
+ can.
+*/
+
+#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;
+
+#ifdef __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) || defined(__BLACKFIN_ASM__)
+ 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) || defined(__BLACKFIN_ASM__)
+ 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 --------------------------------------------------------*/
+
+#ifdef __BLACKFIN_ASM__
+static inline int32_t dot_asm(short *x, short *y, int len)
+{
+ int dot;
+
+ len--;
+
+ __asm__
+ (
+ "I0 = %1;\n\t"
+ "I1 = %2;\n\t"
+ "A0 = 0;\n\t"
+ "R0.L = W[I0++] || R1.L = W[I1++];\n\t"
+ "LOOP dot%= LC0 = %3;\n\t"
+ "LOOP_BEGIN dot%=;\n\t"
+ "A0 += R0.L * R1.L (IS) || R0.L = W[I0++] || R1.L = W[I1++];\n\t"
+ "LOOP_END dot%=;\n\t"
+ "A0 += R0.L*R1.L (IS);\n\t"
+ "R0 = A0;\n\t"
+ "%0 = R0;\n\t"
+ : "=&d" (dot)
+ : "a" (x), "a" (y), "a" (len)
+ : "I0", "I1", "A1", "A0", "R0", "R1"
+ );
+
+ return dot;
+}
+#endif
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ int16_t fir16(fir16_state_t *fir, int16_t sample)
+{
+ int32_t y;
+#if defined(USE_MMX)
+ int i;
+ 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)
+ int i;
+ 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);
+#elif defined(__BLACKFIN_ASM__)
+ fir->history[fir->curr_pos] = sample;
+ fir->history[fir->curr_pos + fir->taps] = sample;
+ y = dot_asm((int16_t*)fir->coeffs, &fir->history[fir->curr_pos], fir->taps);
+#else
+ int i;
+ 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 --------------------------------------------------------*/
+
+#ifndef __KERNEL__
+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 --------------------------------------------------------*/
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+/*- End of file ------------------------------------------------------------*/
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