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Tidy up 16-bit add/subtract to properly use MEMPTR.

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Signed-off-by: Adrian.Conlon <adrian.conlon@gmail.com>
This commit is contained in:
Adrian.Conlon 2017-07-03 21:42:18 +01:00
parent 8f84d57fe1
commit f52edaf8bc
2 changed files with 26 additions and 35 deletions
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22
Z80/inc/Z80.h
View File

@ -255,21 +255,6 @@ namespace EightBit {
}
}
void addViaMemptr(uint8_t& f, register16_t& hl, register16_t operand) {
MEMPTR().word = hl.word + 1;
add(f, hl, operand);
}
void sbcViaMemptr(uint8_t& f, register16_t& hl, register16_t operand) {
MEMPTR().word = hl.word + 1;
sbc(f, hl, operand);
}
void adcViaMemptr(uint8_t& f, register16_t& hl, register16_t operand) {
MEMPTR().word = hl.word + 1;
adc(f, hl, operand);
}
static void adjustHalfCarryAdd(uint8_t& f, uint8_t before, uint8_t value, int calculation) {
setFlag(f, HC, calculateHalfCarryAdd(before, value, calculation));
}
@ -313,10 +298,9 @@ namespace EightBit {
bool jumpConditionalFlag(uint8_t& f, int flag);
bool callConditionalFlag(uint8_t& f, int flag);
static void sbc(uint8_t& f, register16_t& operand, register16_t value);
static void adc(uint8_t& f, register16_t& operand, register16_t value);
static void add(uint8_t& f, register16_t& operand, register16_t value);
void sbc(uint8_t& f, register16_t& operand, register16_t value);
void adc(uint8_t& f, register16_t& operand, register16_t value);
void add(uint8_t& f, register16_t& operand, register16_t value);
static void add(uint8_t& f, uint8_t& operand, uint8_t value, int carry = 0);
static void adc(uint8_t& f, uint8_t& operand, uint8_t value);

39
Z80/src/Z80.cpp
View File

@ -241,58 +241,64 @@ bool EightBit::Z80::callConditionalFlag(uint8_t& f, int flag) {
void EightBit::Z80::sbc(uint8_t& f, register16_t& operand, register16_t value) {
const auto before = operand;
MEMPTR() = operand;
const auto beforeNegative = before.high & SF;
const auto beforeNegative = MEMPTR().high & SF;
const auto valueNegative = value.high & SF;
const auto result = before.word - value.word - (f & CF);
const auto result = MEMPTR().word - value.word - (f & CF);
operand.word = result;
const auto afterNegative = operand.high & SF;
setFlag(f, SF, afterNegative);
clearFlag(f, ZF, operand.word);
adjustHalfCarrySub(f, before.high, value.high, operand.high);
adjustHalfCarrySub(f, MEMPTR().high, value.high, operand.high);
adjustOverflowSub(f, beforeNegative, valueNegative, afterNegative);
setFlag(f, NF);
setFlag(f, CF, result & Bit16);
adjustXY<Z80>(f, operand.high);
MEMPTR().word++;
}
void EightBit::Z80::adc(uint8_t& f, register16_t& operand, register16_t value) {
const auto before = operand;
MEMPTR() = operand;
const auto beforeNegative = before.high & SF;
const auto beforeNegative = MEMPTR().high & SF;
const auto valueNegative = value.high & SF;
const auto result = before.word + value.word + (f & CF);
const auto result = MEMPTR().word + value.word + (f & CF);
operand.word = result;
auto afterNegative = operand.high & SF;
setFlag(f, SF, afterNegative);
clearFlag(f, ZF, operand.word);
adjustHalfCarryAdd(f, before.high, value.high, operand.high);
adjustHalfCarryAdd(f, MEMPTR().high, value.high, operand.high);
adjustOverflowAdd(f, beforeNegative, valueNegative, afterNegative);
clearFlag(f, NF);
setFlag(f, CF, result & Bit16);
adjustXY<Z80>(f, operand.high);
MEMPTR().word++;
}
void EightBit::Z80::add(uint8_t& f, register16_t& operand, register16_t value) {
const auto before = operand;
MEMPTR() = operand;
const auto result = before.word + value.word;
const auto result = MEMPTR().word + value.word;
operand.word = result;
clearFlag(f, NF);
setFlag(f, CF, result & Bit16);
adjustHalfCarryAdd(f, before.high, value.high, operand.high);
adjustHalfCarryAdd(f, MEMPTR().high, value.high, operand.high);
adjustXY<Z80>(f, operand.high);
MEMPTR().word++;
}
#pragma endregion 16-bit arithmetic
@ -677,8 +683,9 @@ void EightBit::Z80::blockOut(uint8_t& f) {
writePort();
postDecrement(f, --B());
setFlag(f, NF, value & Bit7);
setFlag(f, HC | CF, (L() + value) > 0xff);
adjustParity<Z80>(f, ((value + L()) & 7) ^ B());
const auto sum = L() + value;
setFlag(f, HC | CF, sum & Bit16);
adjustParity<Z80>(f, (sum & Mask3) ^ B());
}
void EightBit::Z80::outi(uint8_t& f) {
@ -916,10 +923,10 @@ void EightBit::Z80::executeED(int x, int y, int z, int p, int q) {
case 2: // 16-bit add/subtract with carry
switch (q) {
case 0: // SBC HL, rp[p]
sbcViaMemptr(f, HL2(), RP(p));
sbc(f, HL2(), RP(p));
break;
case 1: // ADC HL, rp[p]
adcViaMemptr(f, HL2(), RP(p));
adc(f, HL2(), RP(p));
break;
default:
__assume(0);
@ -1157,7 +1164,7 @@ void EightBit::Z80::executeOther(int x, int y, int z, int p, int q) {
cycles += 10;
break;
case 1: // ADD HL,rp
addViaMemptr(f, HL2(), RP(p));
add(f, HL2(), RP(p));
cycles += 11;
break;
default: