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Actually, all 6502 getWord usage has an invariant high page indicator.

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Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
This commit is contained in:
Adrian Conlon 2017-12-29 11:50:24 +00:00
parent 7432e602f8
commit 0604d5cf22
2 changed files with 12 additions and 35 deletions
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19
M6502/inc/mos6502.h
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@ -65,7 +65,7 @@ namespace EightBit {
void ADC_d(uint8_t data);
private:
void interrupt(uint16_t vector);
void interrupt(uint8_t vector);
void adjustZero(uint8_t datum) { clearFlag(P(), ZF, datum); }
void adjustNegative(uint8_t datum) { setFlag(P(), NF, datum & NF); }
@ -76,11 +76,6 @@ namespace EightBit {
}
void getWord(uint8_t page, uint8_t offset, register16_t& output);
void getWord(uint8_t offset, register16_t& output);
void getWord(register16_t& output);
void getWord(uint16_t offset, register16_t& output);
void getWord(const register16_t& offset, register16_t& output);
virtual void push(uint8_t value) final;
virtual uint8_t pop() final;
@ -100,7 +95,7 @@ namespace EightBit {
void Address_ZeroPageIndirect() {
Address_ZeroPage();
getWord(MEMPTR().low, MEMPTR());
getWord(0, MEMPTR().low, MEMPTR());
}
void Address_Indirect() {
@ -130,7 +125,7 @@ namespace EightBit {
void Address_IndexedIndirectX() {
Address_ZeroPageX();
getWord(MEMPTR().low, MEMPTR());
getWord(0, MEMPTR().low, MEMPTR());
}
void Address_IndirectIndexedY() {
@ -512,9 +507,11 @@ namespace EightBit {
void BRK();
const uint16_t PageOne = 0x100;
const uint16_t IRQvector = 0xfffe;
const uint16_t RSTvector = 0xfffc;
const uint16_t NMIvector = 0xfffa;
// All interrupt vectors are on the 0xFF page
const uint8_t IRQvector = 0xfe;
const uint8_t RSTvector = 0xfc;
const uint8_t NMIvector = 0xfa;
uint8_t x; // index register X
uint8_t y; // index register Y

28
M6502/src/mos6502.cpp
View File

@ -60,7 +60,7 @@ int EightBit::MOS6502::step() {
void EightBit::MOS6502::reset() {
Processor::reset();
getWord(RSTvector, PC());
getWord(0xff, RSTvector, PC());
}
void EightBit::MOS6502::getWord(uint8_t page, uint8_t offset, register16_t& output) {
@ -71,32 +71,12 @@ void EightBit::MOS6502::getWord(uint8_t page, uint8_t offset, register16_t& outp
output.high = getByte();
}
void EightBit::MOS6502::getWord(uint8_t offset, register16_t& output) {
getWord(0, offset, output);
}
void EightBit::MOS6502::getWord(register16_t& output) {
output.low = getByte();
BUS().ADDRESS().word++;
output.high = getByte();
}
void EightBit::MOS6502::getWord(uint16_t offset, register16_t& output) {
BUS().ADDRESS().word = offset;
getWord(output);
}
void EightBit::MOS6502::getWord(const register16_t& offset, register16_t& output) {
BUS().ADDRESS() = offset;
getWord(output);
}
void EightBit::MOS6502::interrupt(uint16_t vector) {
void EightBit::MOS6502::interrupt(uint8_t vector) {
raise(HALT());
pushWord(PC());
push(P());
setFlag(P(), IF);
getWord(vector, PC());
getWord(0xff, vector, PC());
}
int EightBit::MOS6502::execute(uint8_t cell) {
@ -556,5 +536,5 @@ void EightBit::MOS6502::BRK() {
pushWord(PC());
PHP();
setFlag(P(), IF);
getWord(IRQvector, PC());
getWord(0xff, IRQvector, PC());
}