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Fix ca-cyber with C FPU core.

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@3533
This commit is contained in:
Peter Veenstra 2010-01-12 14:13:23 +00:00
parent 3e936332a5
commit cfbe192e70
1 changed files with 8 additions and 4 deletions
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12
src/fpu/fpu_instructions.h
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@ -118,12 +118,16 @@ static void FPU_ST80(PhysPt addr,Bitu reg) {
} test;
Bit64s sign80 = (fpu.regs[reg].ll&LONGTYPE(0x8000000000000000))?1:0;
Bit64s exp80 = fpu.regs[reg].ll&LONGTYPE(0x7ff0000000000000);
Bit64s exp80final = (exp80>>52) - BIAS64 + BIAS80;
Bit64s exp80final = (exp80>>52);
Bit64s mant80 = fpu.regs[reg].ll&LONGTYPE(0x000fffffffffffff);
Bit64s mant80final = (mant80 << 11);
// Elvira wants the 8 and tcalc doesn't
if(fpu.regs[reg].d != 0) mant80final |= LONGTYPE(0x8000000000000000);
test.begin= (static_cast<Bit16s>(sign80)<<15)| static_cast<Bit16s>(exp80final);
if(fpu.regs[reg].d != 0){ //Zero is a special case
// Elvira wants the 8 and tcalc doesn't
mant80final |= LONGTYPE(0x8000000000000000);
//Ca-cyber doesn't like this when result is zero.
exp80final += (BIAS80 - BIAS64);
}
test.begin = (static_cast<Bit16s>(sign80)<<15)| static_cast<Bit16s>(exp80final);
test.eind.ll = mant80final;
mem_writed(addr,test.eind.l.lower);
mem_writed(addr+4,test.eind.l.upper);