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Z80 eight bit increment/decrement can be simplified a little

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Signed-off-by: Adrian.Conlon <adrian.conlon@gmail.com>
This commit is contained in:
Adrian.Conlon 2017-07-22 10:05:35 +01:00
parent 0a02c32695
commit 19966f6ad8
2 changed files with 15 additions and 15 deletions
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4
Z80/inc/Z80.h
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@ -264,8 +264,8 @@ namespace EightBit {
void executeED(int x, int y, int z, int p, int q);
void executeOther(int x, int y, int z, int p, int q);
static void postIncrement(uint8_t& f, uint8_t value);
static void postDecrement(uint8_t& f, uint8_t value);
static void increment(uint8_t& f, uint8_t& operand);
static void decrement(uint8_t& f, uint8_t& operand);
void retn();
void reti();

26
Z80/src/Z80.cpp
View File

@ -108,18 +108,18 @@ int EightBit::Z80::interrupt(bool maskable, uint8_t value) {
#pragma region Flag manipulation helpers
void EightBit::Z80::postIncrement(uint8_t& f, uint8_t value) {
adjustSZXY<Z80>(f, value);
void EightBit::Z80::increment(uint8_t& f, uint8_t& operand) {
clearFlag(f, NF);
setFlag(f, VF, value == Bit7);
clearFlag(f, HC, lowNibble(value));
adjustSZXY<Z80>(f, ++operand);
setFlag(f, VF, operand == Bit7);
clearFlag(f, HC, lowNibble(operand));
}
void EightBit::Z80::postDecrement(uint8_t& f, uint8_t value) {
adjustSZXY<Z80>(f, value);
void EightBit::Z80::decrement(uint8_t& f, uint8_t& operand) {
setFlag(f, NF);
setFlag(f, VF, value == Mask7);
clearFlag(f, HC, lowNibble(value + 1));
clearFlag(f, HC, lowNibble(operand));
adjustSZXY<Z80>(f, --operand);
setFlag(f, VF, operand == Mask7);
}
#pragma endregion Flag manipulation helpers
@ -636,7 +636,7 @@ void EightBit::Z80::ini(uint8_t& f) {
auto value = m_memory.DATA();
m_memory.ADDRESS().word = HL().word++;
m_memory.reference() = value;
postDecrement(f, --B());
decrement(f, B());
setFlag(f, NF);
}
@ -647,7 +647,7 @@ void EightBit::Z80::ind(uint8_t& f) {
auto value = m_memory.DATA();
m_memory.ADDRESS().word = HL().word--;
m_memory.reference() = value;
postDecrement(f, --B());
decrement(f, B());
setFlag(f, NF);
}
@ -669,7 +669,7 @@ void EightBit::Z80::blockOut(uint8_t& f) {
auto value = m_memory.reference();
m_memory.ADDRESS().word = BC().word;
writePort();
postDecrement(f, --B());
decrement(f, B());
setFlag(f, NF, value & Bit7);
setFlag(f, HC | CF, (L() + value) > 0xff);
adjustParity<Z80>(f, ((value + L()) & 7) ^ B());
@ -1235,11 +1235,11 @@ void EightBit::Z80::executeOther(int x, int y, int z, int p, int q) {
cycles += 6;
break;
case 4: // 8-bit INC
postIncrement(f, ++R(y, a)); // INC r
increment(f, R(y, a)); // INC r
cycles += 4;
break;
case 5: // 8-bit DEC
postDecrement(f, --R(y, a)); // DEC r
decrement(f, R(y, a)); // DEC r
cycles += 4;
if (y == 6)
cycles += 7;