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Whoops: correctly generalise DAA code on the 6809

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Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
This commit is contained in:
Adrian Conlon 2018-08-24 13:05:29 +01:00
parent f8097af5a4
commit bca7977a23
1 changed files with 8 additions and 7 deletions
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15
MC6809/src/mc6809.cpp
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@ -9,7 +9,6 @@ EightBit::mc6809::mc6809(Bus& bus)
int EightBit::mc6809::step() {
resetCycles();
auto returned = 0;
if (LIKELY(powered())) {
m_prefix10 = m_prefix11 = false;
ExecutingInstruction.fire(*this);
@ -787,17 +786,19 @@ void EightBit::mc6809::cwai(uint8_t data) {
uint8_t EightBit::mc6809::da(uint8_t operand) {
clearFlag(CC(), VF);
setFlag(CC(), CF, A() > 0x99);
setFlag(CC(), CF, operand > 0x99);
const auto lowAdjust = halfCarry() || (lowNibble(A()) > 9);
const auto highAdjust = carry() || (A() > 0x99);
const auto lowAdjust = halfCarry() || (lowNibble(operand) > 9);
const auto highAdjust = carry() || (operand > 0x99);
if (lowAdjust)
A() += 6;
operand += 6;
if (highAdjust)
A() += 0x60;
operand += 0x60;
adjustNZ(A());
adjustNZ(operand);
return operand;
}
uint8_t EightBit::mc6809::dec(uint8_t operand) {