cog/Frameworks/GME/gme/Ay_Cpu.h

90 lines
2.1 KiB
C++

// Z80 CPU emulator
// Game_Music_Emu https://bitbucket.org/mpyne/game-music-emu/
#ifndef AY_CPU_H
#define AY_CPU_H
#include "blargg_endian.h"
typedef blargg_long cpu_time_t;
// must be defined by caller
void ay_cpu_out( class Ay_Cpu*, cpu_time_t, unsigned addr, int data );
int ay_cpu_in( class Ay_Cpu*, unsigned addr );
class Ay_Cpu {
public:
// Clear all registers and keep pointer to 64K memory passed in
void reset( void* mem_64k );
// Run until specified time is reached. Returns true if suspicious/unsupported
// instruction was encountered at any point during run.
bool run( cpu_time_t end_time );
// Time of beginning of next instruction
cpu_time_t time() const { return state->time + state->base; }
// Alter current time. Not supported during run() call.
void set_time( cpu_time_t t ) { state->time = t - state->base; }
void adjust_time( int delta ) { state->time += delta; }
#if BLARGG_BIG_ENDIAN
struct regs_t { uint8_t b, c, d, e, h, l, flags, a; };
#else
struct regs_t { uint8_t c, b, e, d, l, h, a, flags; };
#endif
static_assert( sizeof (regs_t) == 8, "Invalid register size, padding issue?" );
struct pairs_t { uint16_t bc, de, hl, fa; };
// Registers are not updated until run() returns
struct registers_t {
uint16_t pc;
uint16_t sp;
uint16_t ix;
uint16_t iy;
union {
regs_t b; // b.b, b.c, b.d, b.e, b.h, b.l, b.flags, b.a
pairs_t w; // w.bc, w.de, w.hl. w.fa
};
union {
regs_t b;
pairs_t w;
} alt;
uint8_t iff1;
uint8_t iff2;
uint8_t r;
uint8_t i;
uint8_t im;
};
//registers_t r; (below for efficiency)
// can read this far past end of memory
enum { cpu_padding = 0x100 };
public:
Ay_Cpu();
private:
uint8_t szpc [0x200];
uint8_t* mem;
cpu_time_t end_time_;
struct state_t {
cpu_time_t base;
cpu_time_t time;
};
state_t* state; // points to state_ or a local copy within run()
state_t state_;
void set_end_time( cpu_time_t t );
public:
registers_t r;
};
inline void Ay_Cpu::set_end_time( cpu_time_t t )
{
cpu_time_t delta = state->base - t;
state->base = t;
state->time += delta;
}
#endif