mirror of
https://github.com/jscrane/r65emu.git
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315 lines
8.8 KiB
C++
315 lines
8.8 KiB
C++
#ifndef __R6502_H__
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#define __R6502_H__
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#undef PC
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class Stream;
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class r6502: public CPU {
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public:
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void raise(int);
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void reset();
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void run(unsigned);
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char *status();
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void checkpoint(Stream &);
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void restore(Stream &);
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r6502 (Memory &, jmp_buf &, CPU::statfn);
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private:
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/* registers */
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Memory::address PC;
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byte S, A, X, Y;
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byte N, V, B, D, I, Z, C;
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union {
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struct {
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unsigned C:1;
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unsigned Z:1;
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unsigned I:1;
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unsigned D:1;
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unsigned B:1;
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unsigned _:1; // unused
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unsigned V:1;
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unsigned N:1;
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} bits;
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byte value;
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} P;
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byte _toBCD[256], _fromBCD[256]; // BCD maps
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bool _irq; // interrupt pending?
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void step();
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void irq();
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void nmi();
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byte flags();
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/* stack */
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inline void pusha (Memory::address ret) {
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_mem[0x0100+S--] = ret >> 8;
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_mem[0x0100+S--] = ret & 0xff;
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}
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inline void pushb (byte b) {
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_mem[0x0100+S--] = b;
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}
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inline byte popb () {
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return _mem[++S+0x0100];
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}
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inline Memory::address popa () {
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byte b = popb ();
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return ((popb () << 8) | b);
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}
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static const Memory::address nmivec = 0xfffa;
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static const Memory::address resvec = 0xfffc;
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static const Memory::address ibvec = 0xfffe;
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inline Memory::address vector(Memory::address v) {
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return (_mem[v+1] << 8) | _mem[v];
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}
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/* operators */
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inline void _cmp (byte a) { Z=N=A-a; C=(A>=a); }
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inline void _cpx (byte a) { Z=N=X-a; C=(X>=a); }
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inline void _cpy (byte a) { Z=N=Y-a; C=(Y>=a); }
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inline void _and (byte a) { Z=N=A&=a; }
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inline void _eor (byte a) { Z=N=A^=a; }
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inline void _ora (byte a) { Z=N=A|=a; }
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inline void _lda (byte a) { Z=N=A=a; }
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inline void _ldx (byte a) { Z=N=X=a; }
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inline void _ldy (byte a) { Z=N=Y=a; }
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/* modes */
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inline Memory::address _a () {
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Memory::address a = _mem[PC++];
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return a | (_mem[PC++] << 8);
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}
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inline Memory::address _ax () { return _a()+X; }
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inline Memory::address _ay () { return _a()+Y; }
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inline Memory::address _z () { return _mem[PC++]; }
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inline Memory::address _zx () { return (_z()+X) & 0xff; }
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inline Memory::address _zy () { return (_z()+Y) & 0xff; }
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inline Memory::address _i (Memory::address a) {
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return (_mem[a+1]<<8)|_mem[a];
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}
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inline Memory::address _ix () { return _i(_zx()); }
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inline Memory::address _iy () { return _i(_mem[PC++])+Y; }
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void _adc (byte a);
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void _sbc (byte a) { if (P.bits.D) sbcd(a); else _adc(~a); }
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void sbcd (byte a);
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inline byte __ror (byte b) {
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N=b>>1; if (C) N|=0x80; C=b&1; return Z=N;
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}
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inline void _ror (Memory::address a) {
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_mem[a] = __ror(_mem[a]);
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}
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inline byte __rol (byte b) {
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N=b<<1; if (C) N|=1; C=(b&0x80)!=0; return Z=N;
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}
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inline void _rol (Memory::address a) {
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_mem[a] = __rol(_mem[a]);
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}
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inline byte __asl (byte b) { C=(b&0x80)!=0; return Z=N=b<<1; }
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inline void _asl (Memory::address a) {
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_mem[a] = __asl(_mem[a]);
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}
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inline byte __lsr (byte b) { C=b&1; Z=b>>1; N=0; return Z; }
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inline void _lsr (Memory::address a) {
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_mem[a] = __lsr(_mem[a]);
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}
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inline void _inc (Memory::address a) {
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Z=N=1+_mem[a]; _mem[a]=Z;
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}
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inline void _dec (Memory::address a) {
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Z=N=_mem[a]-1; _mem[a]=Z;
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}
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inline void _bit (byte z) { V=((z & 0x40)!=0); N=(z & 0x80); Z=(A & z); }
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inline void _bra() {
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byte b = _mem[PC];
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PC += b;
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if (b > 127) PC -= 0x0100;
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}
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/* dispatch table */
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typedef void (r6502::*OP)(); OP _ops[256];
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/* operations */
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void brk ();
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void ora_ix () { _ora (_mem[_ix()]); }
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void ill ();
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void nop2 () { PC++; }
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void ora_z () { _ora (_mem[_z()]); }
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void asl_z () { _asl (_z()); }
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void php ();
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void ora_ () { _ora (_mem[PC++]); }
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void asl () { C=(A&0x80)!=0; Z=N=A<<=1; }
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void nop3 () { PC+=2; }
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void ora_a () { _ora (_mem[_a()]); }
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void asl_a () { _asl (_a()); }
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// 10
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void bpl () { if (!(N & 0x80)) _bra(); PC++; }
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void ora_iy () { _ora (_mem[_iy()]); }
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void ora_zx () { _ora (_mem[_zx()]); }
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void asl_zx () { _asl (_zx()); }
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void clc () { C=0; }
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void ora_ay () { _ora (_mem[_ay()]); }
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void nop () { }
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void ora_ax () { _ora (_mem[_ax()]); }
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void asl_ax () { _asl (_ax()); }
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// 20
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void jsr ();
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void and_ix () { _and (_mem[_ix()]); }
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void bit_z () { _bit (_mem[_z()]); }
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void and_z () { _and (_mem[_z()]); }
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void rol_z () { _rol (_z()); }
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void plp ();
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void and_ () { _and (_mem[PC++]); }
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void rol () { A=__rol (A); }
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void bit_a () { _bit (_mem[_a()]); }
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void and_a () { _and (_mem[_a()]); }
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void rol_a () { _rol (_a()); }
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// 30
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void bmi () { if (N & 0x80) _bra(); PC++; }
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void and_iy () { _and (_mem[_iy()]); }
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void and_zx () { _and (_mem[_zx()]); }
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void rol_zx () { _rol (_zx()); }
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void sec () { C=1; }
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void and_ay () { _and (_mem[_ay()]); }
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void and_ax () { _and (_mem[_ax()]); }
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void rol_ax () { _rol (_ax()); }
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// 40
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void rti ();
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void eor_ix () { _eor (_mem[_ix()]); }
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void eor_z () { _eor (_mem[_z()]); }
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void lsr_z () { _lsr (_z()); }
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void pha () { pushb (A); }
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void eor_ () { _eor (_mem[PC++]); }
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void lsr_ () { A=__lsr(A); }
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void jmp () { PC = _a (); }
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void eor_a () { _eor (_mem[_a()]); }
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void lsr_a () { _lsr (_a()); }
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// 50
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void bvc () { if (!V) _bra(); PC++; }
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void eor_iy () { _eor (_mem[_iy()]); }
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void eor_zx () { _eor (_mem[_zx()]); }
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void lsr_zx () { _lsr (_zx()); }
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void cli ();
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void eor_ay () { _eor (_mem[_ay()]); }
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void eor_ax () { _eor (_mem[_ax()]); }
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void lsr_ax () { _lsr (_ax()); }
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// 60
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void rts ();
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void adc_ix () { _adc (_mem[_ix()]); }
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void adc_z () { _adc (_mem[_z()]); }
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void ror_z () { _ror (_z()); }
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void pla () { Z=N=A=popb (); }
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void adc_ () { _adc (_mem[PC++]); }
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void ror_ () { A=__ror (A); }
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void jmp_i () { PC = _i(_a()); }
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void adc_a () { _adc (_mem[_a()]); }
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void ror_a () { _ror (_a()); }
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// 70
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void bvs () { if (V) _bra(); PC++; }
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void adc_iy () { _adc (_mem[_iy()]); }
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void adc_zx () { _adc (_mem[_zx()]); }
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void ror_zx () { _ror (_zx ()); }
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void sei () { P.bits.I = 1; }
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void adc_ay () { _adc (_mem[_ay()]); }
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void adc_ax () { _adc (_mem[_ax()]); }
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void ror_ax () { _ror (_ax ()); }
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// 80
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void sta_ix () { _mem[_ix()] = A; }
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void sty_z () { _mem[_z()] = Y; }
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void sta_z () { _mem[_z()] = A; }
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void stx_z () { _mem[_z()] = X; }
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void dey () { Z=N=--Y; }
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void txa () { Z=N=A=X; }
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void sty_a () { _mem[_a()] = Y; }
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void sta_a () { _mem[_a()] = A; }
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void stx_a () { _mem[_a()] = X; }
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// 90
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void bcc () { if (!C) _bra(); PC++; }
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void sta_iy () { _mem[_iy()] = A; }
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void sty_zx () { _mem[_zx()] = Y; }
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void sta_zx () { _mem[_zx()] = A; }
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void stx_zy () { _mem[_zy()] = X; }
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void tya () { Z=N=A=Y; }
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void sta_ay () { _mem[_ay()] = A; }
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void txs () { S=X; }
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void sta_ax () { _mem[_ax()] = A; }
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// a0
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void ldy_ () { _ldy (_mem[PC++]); }
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void lda_ix () { _lda (_mem[_ix()]); }
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void ldx_ () { _ldx (_mem[PC++]); }
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void lax_ix () { lda_ix (); X=A; }
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void ldy_z () { _ldy (_mem[_z()]); }
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void lda_z () { _lda (_mem[_z()]); }
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void ldx_z () { _ldx (_mem[_z()]); }
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void lax_z () { lda_z (); X=A; }
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void tay () { Z=N=Y=A; }
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void lda_ () { _lda (_mem[PC++]); }
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void tax () { Z=N=X=A; }
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void ldy_a () { _ldy (_mem[_a()]); }
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void lda_a () { _lda (_mem[_a()]); }
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void ldx_a () { _ldx (_mem[_a()]); }
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void lax_a () { lda_a (); X=A; }
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// b0
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void bcs () { if (C) _bra(); PC++; }
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void lda_iy () { _lda (_mem[_iy()]); }
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void lax_iy () { lda_iy (); X=A; }
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void ldy_zx () { _ldy (_mem[_zx()]); }
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void lda_zx () { _lda (_mem[_zx()]); }
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void ldx_zy () { _ldx (_mem[_zy()]); }
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void lax_zy () { ldx_zy (); A=X; }
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void clv () { V=0; }
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void lda_ay () { _lda (_mem[_ay()]); }
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void tsx () { Z=N=X=S; }
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void ldy_ax () { _ldy (_mem[_ax()]); }
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void lda_ax () { _lda (_mem[_ax()]); }
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void ldx_ay () { _ldx (_mem[_ay()]); }
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void lax_ay () { ldx_ay (); A=X; }
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// c0
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void cpy_ () { _cpy (_mem[PC++]); }
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void cmp_ix () { _cmp (_mem[_ix()]); }
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void cpy_z () { _cpy (_mem[_z()]); }
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void cmp_z () { _cmp (_mem[_z()]); }
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void dec_z () { _dec (_z()); }
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void iny () { Z=N=++Y; }
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void cmp_ () { _cmp (_mem[PC++]); }
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void dex () { Z=N=--X; }
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void cpy_a () { _cpy (_mem[_a()]); }
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void cmp_a () { _cmp (_mem[_a()]); }
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void dec_a () { _dec (_a()); }
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// d0
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void bne () { if (Z) _bra(); PC++; }
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void cmp_iy () { _cmp (_mem[_iy()]); }
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void cmp_zx () { _cmp (_mem[_zx()]); }
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void dec_zx () { _dec (_zx()); }
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void cld () { P.bits.D = 0; }
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void cmp_ay () { _cmp (_mem[_ay()]); }
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void cmp_ax () { _cmp (_mem[_ax()]); }
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void dec_ax () { _dec (_ax()); }
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// e0
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void cpx_ () { _cpx (_mem[PC++]); }
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void sbc_ix () { _sbc (_mem[_ix()]); }
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void cpx_z () { _cpx (_mem[_z()]); }
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void sbc_z () { _sbc (_mem[_z()]); }
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void inc_z () { _inc (_z()); }
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void inx () { Z=N=++X; }
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void sbc_ () { _sbc (_mem[PC++]); }
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void cpx_a () { _cpx (_mem[_a()]); }
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void sbc_a () { _sbc (_mem[_a()]); }
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void inc_a () { _inc (_a()); }
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// f0
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void beq () { if (!Z) _bra(); PC++; }
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void sbc_iy () { _sbc (_mem[_iy()]); }
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void sbc_zx () { _sbc (_mem[_zx()]); }
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void inc_zx () { _inc (_zx()); }
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void sed () { P.bits.D = 1; }
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void sbc_ay () { _sbc (_mem[_ay()]); }
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void sbc_ax () { _sbc (_mem[_ax()]); }
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void inc_ax () { _inc (_ax()); }
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};
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#endif
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