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libavutil/softfloat: Add test case for av_add_sf

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Recently normalization (av_normalize_sf) of output was added to av_add_sf.
This normalization is used for better precision for small values and the
purpose of this (quite simple) test case is to test difference between double
and softfloat.

The values used are tailored to maximally highlighte problem with precison when
normalization is not used.

Signed-off-by: Nedeljko Babic <nedeljko.babic@imgtec.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Nedeljko Babic 2015-05-14 15:36:36 +02:00 committed by Michael Niedermayer
parent 019daa0775
commit 729466dc68
1 changed files with 29 additions and 2 deletions
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31
libavutil/softfloat.c
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@ -26,10 +26,21 @@
#undef printf
static const SoftFloat FLOAT_0_017776489257 = {0x1234, 12};
static const SoftFloat FLOAT_1374_40625 = {0xabcd, 25};
static const SoftFloat FLOAT_0_1249694824218 = {0xFFF, 15};
static av_const double av_sf2double(SoftFloat v) {
v.exp -= ONE_BITS +1;
if(v.exp > 0) return (double)v.mant * (double)(1 << v.exp);
else return (double)v.mant / (double)(1 << (-v.exp));
}
int main(void){
SoftFloat one= av_int2sf(1, 0);
SoftFloat sf1, sf2;
double d1, d2;
SoftFloat sf1, sf2, sf3;
double d1, d2, d3;
int i, j;
av_log_set_level(AV_LOG_DEBUG);
@ -67,5 +78,21 @@ int main(void){
STOP_TIMER("softfloat add mul")
}
printf("test2 sf =%d (%d %d)\n", av_sf2int(sf1, 24), sf1.exp, sf1.mant);
d1 = 0.0177764893;
d2 = 1374.40625;
d3 = 0.1249694824;
d2 += d1;
d3 += d2;
printf("test3 double: %.10lf\n", d3);
sf1 = FLOAT_0_017776489257;
sf2 = FLOAT_1374_40625;
sf3 = FLOAT_0_1249694824218;
sf2 = av_add_sf(sf1, sf2);
sf3 = av_add_sf(sf3, sf2);
printf("test3 softfloat: %.10lf (0x%08x %d)\n", (double)av_sf2double(sf3), sf3.mant, sf3.exp);
return 0;
}