bsnes/gameboy/cpu/cpu.cpp

133 lines
3.2 KiB
C++
Executable File

#include <gameboy/gameboy.hpp>
#define CPU_CPP
namespace GameBoy {
#include "core/core.cpp"
#include "mmio/mmio.cpp"
#include "timing/timing.cpp"
CPU cpu;
void CPU::Main() {
cpu.main();
}
void CPU::main() {
while(true) {
if(trace) print(disassemble(r[PC]), "\n");
interrupt_test();
uint8 opcode = op_read(r[PC]++);
(this->*opcode_table[opcode])();
}
}
void CPU::interrupt_raise(CPU::Interrupt id) {
switch(id) {
case Interrupt::Vblank: status.interrupt_request_vblank = 1; break;
case Interrupt::Stat : status.interrupt_request_stat = 1; break;
case Interrupt::Timer : status.interrupt_request_timer = 1; break;
case Interrupt::Serial: status.interrupt_request_serial = 1; break;
case Interrupt::Joypad: status.interrupt_request_joypad = 1; status.stop = false; break;
}
status.halt = false;
}
void CPU::interrupt_test() {
if(status.ime) {
if(status.interrupt_request_vblank && status.interrupt_enable_vblank) {
status.interrupt_request_vblank = 0;
return interrupt_exec(0x0040);
}
if(status.interrupt_request_stat && status.interrupt_enable_stat) {
status.interrupt_request_stat = 0;
return interrupt_exec(0x0048);
}
if(status.interrupt_request_timer && status.interrupt_enable_timer) {
status.interrupt_request_timer = 0;
return interrupt_exec(0x0050);
}
if(status.interrupt_request_serial && status.interrupt_enable_serial) {
status.interrupt_request_serial = 0;
return interrupt_exec(0x0058);
}
if(status.interrupt_request_joypad && status.interrupt_enable_joypad) {
status.interrupt_request_joypad = 0;
return interrupt_exec(0x0060);
}
}
}
void CPU::interrupt_exec(uint16 pc) {
status.ime = 0;
op_write(--r[SP], r[PC] >> 8);
op_write(--r[SP], r[PC] >> 0);
r[PC] = pc;
op_io();
op_io();
op_io();
}
void CPU::power() {
create(Main, 4 * 1024 * 1024);
for(unsigned n = 0xc000; n <= 0xdfff; n++) bus.mmio[n] = this; //WRAM
for(unsigned n = 0xe000; n <= 0xfdff; n++) bus.mmio[n] = this; //WRAM (mirror)
for(unsigned n = 0xff00; n <= 0xff0f; n++) bus.mmio[n] = this; //MMIO
for(unsigned n = 0xff80; n <= 0xffff; n++) bus.mmio[n] = this; //HRAM+IE
for(unsigned n = 0; n < 8192; n++) wram[n] = 0x00;
for(unsigned n = 0; n < 128; n++) hram[n] = 0x00;
r[PC] = 0x0100;
r[SP] = 0xfffe;
r[AF] = 0x0100;
r[BC] = 0x0000;
r[DE] = 0x0000;
r[HL] = 0x0000;
status.clock = 0;
status.halt = false;
status.stop = false;
status.ime = 0;
status.timer0 = 0;
status.timer1 = 0;
status.timer2 = 0;
status.timer3 = 0;
status.p15 = 0;
status.p14 = 0;
status.joyp = 0;
status.div = 0;
status.tima = 0;
status.tma = 0;
status.timer_enable = 0;
status.timer_clock = 0;
status.interrupt_request_joypad = 0;
status.interrupt_request_serial = 0;
status.interrupt_request_timer = 0;
status.interrupt_request_stat = 0;
status.interrupt_request_vblank = 0;
status.interrupt_enable_joypad = 0;
status.interrupt_enable_serial = 0;
status.interrupt_enable_timer = 0;
status.interrupt_enable_stat = 0;
status.interrupt_enable_vblank = 0;
}
CPU::CPU() : trace(false) {
initialize_opcode_table();
}
}