bsnes/higan/processor/z80/z80.cpp

59 lines
1000 B
C++

#include <processor/processor.hpp>
#include "z80.hpp"
namespace Processor {
#include "disassembler.cpp"
#include "registers.cpp"
#include "memory.cpp"
#include "instruction.cpp"
#include "instructions.cpp"
auto Z80::power() -> void {
memory::fill(&r, sizeof(Registers));
r.hlp = &r.hl;
}
auto Z80::irq(bool maskable, uint16 pc, uint8 extbus) -> bool {
if(maskable && !r.iff1) return false;
push(r.pc);
switch(maskable ? r.im : (uint2)1) {
case 0: {
//external data bus ($ff = RST $38)
r.pc = extbus;
break;
}
case 1: {
//constant address
r.pc = pc;
break;
}
case 2: {
//vector table with external data bus
uint16 addr = (r.ir.byte.hi << 8) | extbus;
r.pc = read(addr + 0) << 0;
r.pc |= read(addr + 1) << 8;
break;
}
}
r.iff1 = 0;
if(maskable) r.iff2 = 0;
return true;
}
auto Z80::parity(uint8 value) const -> bool {
value ^= value >> 4;
value ^= value >> 2;
value ^= value >> 1;
return !(value & 1);
}
}