floating point "emulation" code

unused currently, but might come in handy for some fpu-less cpus

Originally committed as revision 5955 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavutil/softfloat.c

@@ -0,0 +1,52 @@
+#include <inttypes.h>
+#include <stdio.h>
+#include <assert.h>
+#include "softfloat.h"
+#include "common.h"
+#include "log.h"
+
+#undef printf
+
+int main(){
+    SoftFloat one= av_int2sf(1, 0);
+    SoftFloat sf1, sf2;
+    double d1, d2;
+    int i, j;
+av_log_level = AV_LOG_DEBUG;
+
+    d1= 1;
+    for(i= 0; i<10; i++){
+        d1= 1/(d1+1);
+    }
+    printf("test1 double=%d\n", (int)(d1 * (1<<24)));
+
+    sf1= one;
+    for(i= 0; i<10; i++){
+        sf1= av_div_sf(one, av_normalize_sf(av_add_sf(one, sf1)));
+    }
+    printf("test1 sf    =%d\n", av_sf2int(sf1, 24));
+
+
+    for(i= 0; i<100; i++){
+        START_TIMER
+        d1= i;
+        d2= i/100.0;
+        for(j= 0; j<1000; j++){
+            d1= (d1+1)*d2;
+        }
+        STOP_TIMER("float add mul")
+    }
+    printf("test2 double=%d\n", (int)(d1 * (1<<24)));
+
+    for(i= 0; i<100; i++){
+        START_TIMER
+        sf1= av_int2sf(i, 0);
+        sf2= av_div_sf(av_int2sf(i, 2), av_int2sf(200, 3));
+        for(j= 0; j<1000; j++){
+            sf1= av_mul_sf(av_add_sf(sf1, one),sf2);
+        }
+        STOP_TIMER("softfloat add mul")
+    }
+    printf("test2 sf    =%d (%d %d)\n", av_sf2int(sf1, 24), sf1.exp, sf1.mant);
+    return 0;
+}