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corrected thumb2 EOR instruction. shift type was wrong

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JetSetIlly 2024-03-05 10:43:43 +00:00
parent 954c1485a1
commit d9e0bd0380
1 changed files with 7 additions and 3 deletions
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10
hardware/memory/cartridge/arm/thumb2_32bit.go
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@ -587,15 +587,19 @@ func (arm *ARM) decode32bitThumb2DataProcessingNonImmediate(opcode uint16) decod
m := uint32(0x01) << (imm5 - 1)
carry = arm.state.registers[Rm]&m == m
result = arm.state.registers[Rn] ^ (arm.state.registers[Rm] >> imm5)
case 0b11:
case 0b10:
// with arithmetic right shift
signExtend := (arm.state.registers[Rm] & 0x80000000) >> 31
result = arm.state.registers[Rn] ^ (arm.state.registers[Rm] >> imm5)
if signExtend == 0x01 {
result |= ^uint32(0) << (32 - imm5)
}
default:
panic("impossible shift for EOR instruction")
case 0b11:
if imm5 == 0b00000 {
result, carry = RRX_C(arm.state.registers[Rm], arm.state.status.carry)
} else {
result, carry = ROR_C(arm.state.registers[Rm], uint32(imm5))
}
}
// perform EOR or do nothing if this is just a TST