--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.3/user/tfir.c	Fri Jun 25 16:00:21 2010 +0200
@@ -0,0 +1,154 @@
+/*
+   tfir.c
+   David Rowe
+   Created 30 May 2007
+
+   Test program for Spandsp fir2 function, used for developing optimised
+   Blackfin assembler.
+*/
+
+/*
+  Copyright (C) 2007 David Rowe
+ 
+  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.
+*/
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <inttypes.h>
+
+#include "fir.h"
+
+#define TAPS 256
+#define N    100
+
+/* C-callable function to return value of CYCLES register */
+
+int cycles() {
+  int ret;
+
+   __asm__ __volatile__ 
+   (
+   "%0 = CYCLES;\n\t"
+   : "=&d" (ret)
+   : 
+   : "R1"
+   );
+
+   return ret;
+}
+
+static int32_t dot(int16_t *x, int16_t *y, int n) {
+    int32_t acc = 0;
+    int     i;
+
+    for(i=0; i<n; i++)
+	acc += *x++ * *y++;
+
+    return acc;
+}
+
+#ifdef FIRST_TRY
+static int16_t fir16_asm(fir16_state_t *fir, int16_t sample)
+{
+    int i;
+    int32_t y, y_dot;
+    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]; 
+    y_dot = 0;
+    y_dot += dot_asm((int16_t*)&fir->coeffs[offset1], fir->history, fir->curr_pos);
+    printf("offset1 %d offset2: %d y = %d  y_dot = %d\n", offset1, offset2, y, y_dot);
+    assert(y_dot == y);
+
+    for (  ;  i >= 0;  i--)
+        y += fir->coeffs[i]*fir->history[i + offset2];
+    y_dot += dot((int16_t*)fir->coeffs, &fir->history[offset2], offset1);
+    assert(y_dot == y);
+
+    if (fir->curr_pos <= 0)
+    	fir->curr_pos = fir->taps;
+    fir->curr_pos--;
+    return (int16_t) (y >> 15);
+}
+#endif
+
+static int16_t fir16_asm(fir16_state_t *fir, int16_t sample)
+{
+    int i;
+    int32_t y, y_dot;
+
+    fir->history[fir->curr_pos] = sample;
+    fir->history[fir->curr_pos + fir->taps] = sample;
+
+    /*
+    y = 0;
+    for (i=0; i<fir->taps; i++)
+        y += fir->coeffs[i]*fir->history[fir->curr_pos+i]; 
+    */
+    y_dot = dot_asm((int16_t*)fir->coeffs, &fir->history[fir->curr_pos], fir->taps);
+    //assert(y_dot == y);
+    
+    if (fir->curr_pos <= 0)
+    	fir->curr_pos = fir->taps;
+    fir->curr_pos--;
+    return (int16_t) (y_dot >> 15);
+}
+
+int main() {
+    int16_t       taps[TAPS];
+    fir16_state_t fir, fir_asm;
+    int16_t       out, out_asm, in;
+    int           i, before;
+
+    for(i=0; i<TAPS; i++)
+	taps[i] = 0x8000;
+    
+    fir16_create(&fir, taps, TAPS);
+    fir16_create(&fir_asm, taps, TAPS);
+
+    /* first check the results are the same for C and asm */
+
+    for(i=0; i<N; i++) {
+	in = i;
+	out = fir16(&fir, in);
+	out_asm = fir16_asm(&fir_asm, in);
+	//printf("[%d] out = %d  out_asm = %d\n", i, out, out_asm);
+	assert(out == out_asm);
+    }
+
+    printf("OK\n");
+
+    /* now measure the speed */
+
+    before = cycles();
+    out = fir16(&fir, in);
+    printf("C version: %d cycles\n", cycles() - before);
+    before = cycles();
+    out_asm = fir16_asm(&fir_asm, in);
+    printf("ASM version: %d cycles\n", cycles() - before);
+
+    return 0;
+}