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Detect +/- INF when loading a 80bit

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@3614
This commit is contained in:
Peter Veenstra 2010-06-09 19:09:39 +00:00
parent b441536ff4
commit d7404e0ba4
1 changed files with 6 additions and 1 deletions
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7
src/fpu/fpu_instructions.h
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@ -97,7 +97,7 @@ static Real64 FPU_FLD80(PhysPt addr) {
test.eind.l.lower = mem_readd(addr);
test.eind.l.upper = mem_readd(addr+4);
test.begin = mem_readw(addr+8);
Bit64s exp64 = (((test.begin&0x7fff) - BIAS80));
Bit64s blah = ((exp64 >0)?exp64:-exp64)&0x3ff;
Bit64s exp64final = ((exp64 >0)?blah:-blah) +BIAS64;
@ -106,6 +106,11 @@ static Real64 FPU_FLD80(PhysPt addr) {
Bit64s sign = (test.begin&0x8000)?1:0;
FPU_Reg result;
result.ll = (sign <<63)|(exp64final << 52)| mant64;
if(test.eind.l.lower == 0 && test.eind.l.upper == 0x80000000 && (test.begin&0x7fff) == 0x7fff) {
//Detect INF and -INF (score 3.11 when drawing a slur.)
result.d = sign?-HUGE_VAL:HUGE_VAL;
}
return result.d;
//mant64= test.mant80/2***64 * 2 **53