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armjit: Implement a software divide for divu.

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It's not actually that much code.
This commit is contained in:
Unknown W. Brackets 2013-11-09 03:06:35 -08:00
parent b2a240d105
commit 1776c85882
1 changed files with 41 additions and 3 deletions
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44
Core/MIPS/ARM/ArmCompALU.cpp
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@ -706,15 +706,53 @@ namespace MIPSComp
break;
case 27: //divu
if (cpu_info.bIDIVa)
{
if (cpu_info.bIDIVa) {
// TODO: Does this handle INT_MAX, 0, etc. correctly?
gpr.MapDirtyDirtyInIn(MIPS_REG_LO, MIPS_REG_HI, rs, rt);
UDIV(gpr.R(MIPS_REG_LO), gpr.R(rs), gpr.R(rt));
MUL(R0, gpr.R(rt), gpr.R(MIPS_REG_LO));
SUB(gpr.R(MIPS_REG_HI), gpr.R(rs), Operand2(R0));
} else {
DISABLE;
gpr.MapDirtyDirtyInIn(MIPS_REG_LO, MIPS_REG_HI, rs, rt);
MOV(R0, gpr.R(rt));
CMP(gpr.R(rt), 0);
SetCC(CC_EQ);
// Just set to a really high number, can't divide by zero.
MVN(R0, 0);
SetCC(CC_AL);
// Double R0 until it would be (but isn't) bigger than the numerator.
CMP(R0, Operand2(gpr.R(rs), ST_LSR, 1));
const u8 *doubleLoop = GetCodePtr();
SetCC(CC_LS);
MOV(R0, Operand2(R0, ST_LSL, 1));
SetCC(CC_AL);
CMP(R0, Operand2(gpr.R(rs), ST_LSR, 1));
B_CC(CC_LS, doubleLoop);
MOV(gpr.R(MIPS_REG_HI), gpr.R(rs));
MOV(gpr.R(MIPS_REG_LO), 0);
// Subtract and halve R0 (doubling and adding the result) until it's below the denominator.
const u8 *subLoop = GetCodePtr();
CMP(gpr.R(MIPS_REG_HI), R0);
SetCC(CC_HS);
SUB(gpr.R(MIPS_REG_HI), gpr.R(MIPS_REG_HI), R0);
SetCC(CC_AL);
// Carry will be set if we subtracted.
ADC(gpr.R(MIPS_REG_LO), gpr.R(MIPS_REG_LO), gpr.R(MIPS_REG_LO));
MOV(R0, Operand2(R0, ST_LSR, 1));
CMP(R0, gpr.R(rt));
B_CC(CC_HS, subLoop);
// We didn't change rt. If it was 0, then clear HI and LO.
// TODO: Is this correct?
CMP(gpr.R(rt), 0);
SetCC(CC_EQ);
MOV(gpr.R(MIPS_REG_LO), 0);
MOV(gpr.R(MIPS_REG_HI), 0);
SetCC(CC_AL);
}
break;