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