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UserspaceEmulator: Add single-operand MUL and DIV instructions

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These are the unsigned variants. Signed variants sold separately.
This commit is contained in:
Andreas Kling 2020-07-18 16:05:47 +02:00
parent 30d512144e
commit 02882d5345
1 changed files with 53 additions and 4 deletions
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57
DevTools/UserspaceEmulator/SoftCPU.cpp
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@ -1198,7 +1198,23 @@ void SoftCPU::DEC_reg32(const X86::Instruction& insn)
gpr32(insn.reg32()) = op_dec(*this, gpr32(insn.reg32()));
}
void SoftCPU::DIV_RM16(const X86::Instruction&) { TODO(); }
void SoftCPU::DIV_RM16(const X86::Instruction& insn)
{
auto divisor = insn.modrm().read16(*this, insn);
if (divisor == 0) {
warn() << "Divide by zero";
TODO();
}
u32 dividend = ((u32)dx() << 16) | ax();
auto result = dividend / divisor;
if (result > NumericLimits<u16>::max()) {
warn() << "Divide overflow";
TODO();
}
set_ax(result);
set_dx(dividend % divisor);
}
void SoftCPU::DIV_RM32(const X86::Instruction& insn)
{
@ -1218,7 +1234,24 @@ void SoftCPU::DIV_RM32(const X86::Instruction& insn)
set_edx(dividend % divisor);
}
void SoftCPU::DIV_RM8(const X86::Instruction&) { TODO(); }
void SoftCPU::DIV_RM8(const X86::Instruction& insn)
{
auto divisor = insn.modrm().read8(*this, insn);
if (divisor == 0) {
warn() << "Divide by zero";
TODO();
}
u16 dividend = ax();
auto result = dividend / divisor;
if (result > NumericLimits<u8>::max()) {
warn() << "Divide overflow";
TODO();
}
set_al(result);
set_ah(dividend % divisor);
}
void SoftCPU::ENTER16(const X86::Instruction&) { TODO(); }
void SoftCPU::ENTER32(const X86::Instruction&) { TODO(); }
@ -1647,7 +1680,16 @@ void SoftCPU::MOV_reg8_imm8(const X86::Instruction& insn)
void SoftCPU::MOV_seg_RM16(const X86::Instruction&) { TODO(); }
void SoftCPU::MOV_seg_RM32(const X86::Instruction&) { TODO(); }
void SoftCPU::MUL_RM16(const X86::Instruction&) { TODO(); }
void SoftCPU::MUL_RM16(const X86::Instruction& insn)
{
u32 result = (u32)ax() * (u32)insn.modrm().read16(*this, insn);
set_ax(result & 0xffff);
set_dx(result >> 16);
set_cf(dx() != 0);
set_of(dx() != 0);
}
void SoftCPU::MUL_RM32(const X86::Instruction& insn)
{
@ -1659,7 +1701,14 @@ void SoftCPU::MUL_RM32(const X86::Instruction& insn)
set_of(edx() != 0);
}
void SoftCPU::MUL_RM8(const X86::Instruction&) { TODO(); }
void SoftCPU::MUL_RM8(const X86::Instruction& insn)
{
u16 result = (u16)al() * insn.modrm().read8(*this, insn);
set_ax(result);
set_cf((result & 0xff00) != 0);
set_of((result & 0xff00) != 0);
}
void SoftCPU::NEG_RM16(const X86::Instruction& insn)
{