lsnes/nes/cpu/memory/memory.cpp
2013-05-03 17:47:34 +03:00

59 lines
1 KiB
C++
Executable file

uint8 CPU::op_read(uint16 addr) {
if(status.oam_dma_pending) {
status.oam_dma_pending = false;
op_read(addr);
oam_dma();
}
while(status.rdy_line == 0) {
regs.mdr = bus.read(status.rdy_addr ? status.rdy_addr() : addr);
add_clocks(12);
}
regs.mdr = bus.read(addr);
add_clocks(12);
return regs.mdr;
}
void CPU::op_write(uint16 addr, uint8 data) {
bus.write(addr, regs.mdr = data);
add_clocks(12);
}
//
uint8 CPU::op_readpc() {
return op_read(regs.pc);
}
uint8 CPU::op_readpci() {
return op_read(regs.pc++);
}
uint8 CPU::op_readsp() {
return op_read(0x0100 | ++regs.s);
}
uint8 CPU::op_readzp(uint8 addr) {
return op_read(addr);
}
//
void CPU::op_writesp(uint8 data) {
op_write(0x0100 | regs.s--, data);
}
void CPU::op_writezp(uint8 addr, uint8 data) {
op_write(addr, data);
}
//
void CPU::op_page(uint16 x, uint16 y) {
if((x & 0xff00) != (y & 0xff00)) op_read((x & 0xff00) | (y & 0x00ff));
}
void CPU::op_page_always(uint16 x, uint16 y) {
op_read((x & 0xff00) | (y & 0x00ff));
}