From 93403d5a8ee492bd922d9e9688f5c1d3bb3edccf Mon Sep 17 00:00:00 2001
From: Stephen Crane <jscrane@gmail.com>
Date: Wed, 19 Nov 2014 19:35:16 +0000
Subject: [PATCH] add step for debugging

---
 cpu.h     |   3 +-
 r6502.cpp | 391 +++++++++++++++++++++++++++---------------------------
 r6502.h   |   1 +
 3 files changed, 202 insertions(+), 193 deletions(-)

diff --git a/cpu.h b/cpu.h
index f99f93b..5810f6c 100644
--- a/cpu.h
+++ b/cpu.h
@@ -7,8 +7,9 @@
 
 class CPU: public Checkpointable {
 public:
+	virtual Memory::address run(unsigned instructions) =0;
 	virtual void reset () =0;
-	virtual Memory::address run (unsigned instructions) =0;
+	virtual Memory::address step() =0;
 	virtual void raise (int level) =0;
 	virtual char *status () =0;
 
diff --git a/r6502.cpp b/r6502.cpp
index 0f49438..6d7c92f 100644
--- a/r6502.cpp
+++ b/r6502.cpp
@@ -5,262 +5,269 @@
 #include "cpu.h"
 #include "r6502.h"
 
-Memory::address r6502::run (unsigned clocks) {
-  while (clocks--) 
-  {
-    byte op = (*_memory)[PC];
+Memory::address r6502::step() {
+	byte op = (*_memory)[PC];
 #ifdef CPU_DEBUG
-    if (_debug)
-      _status ("%04x: %02x [%02x %02x %02x, %02x]\r", PC, op, A, X, Y, flags());
+	if (_debug)
+		_status ("%04x: %02x [%02x %02x %02x, %02x]\r", PC, op, A, X, Y, flags());
 #endif
-    PC++;
-    (this->*_ops[op])();
-  }
-  return PC;
+	PC++;
+	(this->*_ops[op])();
+	return PC;
+}
+
+Memory::address r6502::run(unsigned clocks) {
+#ifdef CPU_DEBUG
+	if (_debug)
+		return step();
+#endif
+	while (clocks--) 
+		step();
+	return PC;
 }
 
 byte r6502::flags() {
-  P.bits.N = ((N & 0x80) != 0);
-  P.bits.V = V;
-  P.bits.Z = !Z;
-  P.bits.C = C;
-  P.bits._ = 1;
-  return P.value;
+	P.bits.N = ((N & 0x80) != 0);
+	P.bits.V = V;
+	P.bits.Z = !Z;
+	P.bits.C = C;
+	P.bits._ = 1;
+	return P.value;
 }
 
 char *r6502::status () {
-  static char buf[128];
-  flags();
-  sprintf (buf, "aa xx yy sp nv_bdizc  _pc_\r\n"
-     "%02x %02x %02x %02x %d%d%d%d%d%d%d%d  %04x\r\n", 
-     A, X, Y, S, P.bits.N, P.bits.V, P.bits._, P.bits.B, 
-     P.bits.D, P.bits.I, P.bits.Z, P.bits.C, PC);
-  return buf;
+	static char buf[128];
+	flags();
+	sprintf (buf, "aa xx yy sp nv_bdizc	_pc_\r\n"
+		 "%02x %02x %02x %02x %d%d%d%d%d%d%d%d	%04x\r\n", 
+		 A, X, Y, S, P.bits.N, P.bits.V, P.bits._, P.bits.B, 
+		 P.bits.D, P.bits.I, P.bits.Z, P.bits.C, PC);
+	return buf;
 }
 
 void r6502::checkpoint(Stream &s)
 {
-  s.write(PC / 0xff);
-  s.write(PC % 0xff);
-  s.write(S);  
-  s.write(A);  
-  s.write(X);  
-  s.write(Y);  
-  s.write(N);  
-  s.write(V);  
-  s.write(B);  
-  s.write(D);  
-  s.write(I);  
-  s.write(Z);  
-  s.write(C);  
-  s.write(P.value);  
+	s.write(PC / 0xff);
+	s.write(PC % 0xff);
+	s.write(S);	
+	s.write(A);	
+	s.write(X);	
+	s.write(Y);	
+	s.write(N);	
+	s.write(V);	
+	s.write(B);	
+	s.write(D);	
+	s.write(I);	
+	s.write(Z);	
+	s.write(C);	
+	s.write(P.value);	
 }
 
 void r6502::restore(Stream &s)
 {
-  byte hi = s.read(), lo = s.read();
-  PC = hi * 0xff + lo;
-  S = s.read();
-  A = s.read();
-  X = s.read();
-  Y = s.read();
-  N = s.read();
-  V = s.read();
-  B = s.read();
-  D = s.read();
-  I = s.read();
-  Z = s.read();
-  C = s.read();
-  P.value = s.read();
+	byte hi = s.read(), lo = s.read();
+	PC = hi * 0xff + lo;
+	S = s.read();
+	A = s.read();
+	X = s.read();
+	Y = s.read();
+	N = s.read();
+	V = s.read();
+	B = s.read();
+	D = s.read();
+	I = s.read();
+	Z = s.read();
+	C = s.read();
+	P.value = s.read();
 }
 
 void r6502::raise (int level) {
-  if (level < 0)
-    nmi ();
-  else if (!P.bits.I)
-    irq ();
-  else
-    _irq = true;
+	if (level < 0)
+		nmi ();
+	else if (!P.bits.I)
+		irq ();
+	else
+		_irq = true;
 }
 
 void r6502::irq () {
-  pusha (PC);
-  P.bits.B = 0;
-  pushb (flags ());
-  P.bits.B = 1;
-  P.bits.I = 1;
-  PC = vector (ibvec);
-  _irq = false;
+	pusha (PC);
+	P.bits.B = 0;
+	pushb (flags ());
+	P.bits.B = 1;
+	P.bits.I = 1;
+	PC = vector (ibvec);
+	_irq = false;
 }
 
 void r6502::brk () {
-  if (!P.bits.I) {
-    pusha (PC);
-    P.bits.B = 1;
-    php ();
-    P.bits.I = 1;
-    PC = vector (ibvec);
-  }
-  P.bits.B = 1;
-  P.bits._ = 1;
+	if (!P.bits.I) {
+		pusha (PC);
+		P.bits.B = 1;
+		php ();
+		P.bits.I = 1;
+		PC = vector (ibvec);
+	}
+	P.bits.B = 1;
+	P.bits._ = 1;
 }
 
 void r6502::rti () {
-  plp ();
-  PC = popa ();
+	plp ();
+	PC = popa ();
 }
 
 void r6502::cli () {
-  P.bits.I = 0;
-  if (_irq)
-    irq();
+	P.bits.I = 0;
+	if (_irq)
+		irq();
 }
 
 void r6502::nmi () {
-  pusha (PC);
-  php ();
-  P.bits.I = 1;
-  PC = vector (nmivec);
+	pusha (PC);
+	php ();
+	P.bits.I = 1;
+	PC = vector (nmivec);
 }
 
 // php and plp are complicated by the representation
 // of the processor state for efficient normal operation
 void r6502::php () {
-  P.bits.B = 1;
-  pushb (flags ());
+	P.bits.B = 1;
+	pushb (flags ());
 }
 
 void r6502::plp () {
-  P.value = popb ();
-  N = P.bits.N? 0x80: 0;
-  V = P.bits.V;
-  Z = !P.bits.Z;
-  C = P.bits.C;
+	P.value = popb ();
+	N = P.bits.N? 0x80: 0;
+	V = P.bits.V;
+	Z = !P.bits.Z;
+	C = P.bits.C;
 }
 
 void r6502::rts () {
-  PC = popa ()+1;
+	PC = popa ()+1;
 }
 
 void r6502::jsr () {
-  pusha (PC+1);
-  PC = vector (PC);
+	pusha (PC+1);
+	PC = vector (PC);
 }
 
 void r6502::_adc (byte d) {
-  if (P.bits.D) {
-    int r = _fromBCD[A] + _fromBCD[d] + C;
-    C = (r > 99);
-    if (C) r -= 100;
-    A = _toBCD[r];
-  } else {
-    unsigned short u = (unsigned short)A + (unsigned short)d + (unsigned short)C;
-    short s = (char)A + (char)d + (char)C;
-    C = (u < 0 || u > 255);
-    V = (s > 127 || s < -128);
-    A = (u & 0xff);
-  }
-  N = (A & 0x80);
-  Z = A;
+	if (P.bits.D) {
+		int r = _fromBCD[A] + _fromBCD[d] + C;
+		C = (r > 99);
+		if (C) r -= 100;
+		A = _toBCD[r];
+	} else {
+		unsigned short u = (unsigned short)A + (unsigned short)d + (unsigned short)C;
+		short s = (char)A + (char)d + (char)C;
+		C = (u < 0 || u > 255);
+		V = (s > 127 || s < -128);
+		A = (u & 0xff);
+	}
+	N = (A & 0x80);
+	Z = A;
 }
 
 void r6502::sbcd (byte d) {
-  int r = _fromBCD[A] - _fromBCD[d] - !C;
-  C = (r >= 0);
-  if (r < 0) r += 100;
-  A = _toBCD[r & 0xff];
-  N = (A & 0x80);
-  Z = A;
-  // V not tested for: http://www.6502.org/tutorials/decimal_mode.html
+	int r = _fromBCD[A] - _fromBCD[d] - !C;
+	C = (r >= 0);
+	if (r < 0) r += 100;
+	A = _toBCD[r & 0xff];
+	N = (A & 0x80);
+	Z = A;
+	// V not tested for: http://www.6502.org/tutorials/decimal_mode.html
 }
 
 void r6502::ill () {
-  _status ("Illegal instruction at %04x!\r\n%s", (PC-1), status());
-  longjmp (*_err, 1);
+	_status ("Illegal instruction at %04x!\r\n%s", (PC-1), status());
+	longjmp (*_err, 1);
 }
 
 void r6502::reset ()
 {
-  _debug = false;
-  P.value = 0;
-  P.bits._ = 1;
-  P.bits.B = 1;
-  _irq = false;
-  S = 0xff;
-  PC = vector(resvec);
+	_debug = false;
+	P.value = 0;
+	P.bits._ = 1;
+	P.bits.B = 1;
+	_irq = false;
+	S = 0xff;
+	PC = vector(resvec);
 }
 
 r6502::r6502 (Memory *m, jmp_buf *e, CPU::statfn s): CPU (m,e,s) {
 
-  for (int i=0; i < 256; i++) {
-    _fromBCD[i] = ((i >> 4) & 0x0f)*10 + (i & 0x0f);
-    _toBCD[i] = (((i % 100) / 10) << 4) | (i % 10);
-  }
-    
-  OP *p = _ops;
-  *p++=&r6502::brk; *p++=&r6502::ora_ix; *p++=&r6502::ill; *p++=&r6502::ill; 
-  *p++=&r6502::nop2; *p++=&r6502::ora_z; *p++=&r6502::asl_z; *p++=&r6502::ill;
-  *p++=&r6502::php; *p++=&r6502::ora_; *p++=&r6502::asl; *p++=&r6502::ill; 
-  *p++=&r6502::nop3; *p++=&r6502::ora_a; *p++=&r6502::asl_a; *p++=&r6502::ill;
-  *p++=&r6502::bpl; *p++=&r6502::ora_iy; *p++=&r6502::ill; *p++=&r6502::ill; 
-  *p++=&r6502::nop2; *p++=&r6502::ora_zx; *p++=&r6502::asl_zx; *p++=&r6502::ill;
-  *p++=&r6502::clc; *p++=&r6502::ora_ay; *p++=&r6502::nop; *p++=&r6502::ill; 
-  *p++=&r6502::nop2; *p++=&r6502::ora_ax; *p++=&r6502::asl_ax; *p++=&r6502::ill;
-  *p++=&r6502::jsr; *p++=&r6502::and_ix; *p++=&r6502::ill; *p++=&r6502::ill; 
-  *p++=&r6502::bit_z; *p++=&r6502::and_z; *p++=&r6502::rol_z; *p++=&r6502::ill;
-  *p++=&r6502::plp; *p++=&r6502::and_; *p++=&r6502::rol; *p++=&r6502::ill; 
-  *p++=&r6502::bit_a; *p++=&r6502::and_a; *p++=&r6502::rol_a; *p++=&r6502::ill;
-  *p++=&r6502::bmi; *p++=&r6502::and_iy; *p++=&r6502::ill; *p++=&r6502::ill; 
-  *p++=&r6502::nop2; *p++=&r6502::and_zx; *p++=&r6502::rol_zx; *p++=&r6502::ill;
-  *p++=&r6502::sec; *p++=&r6502::and_ay; *p++=&r6502::nop; *p++=&r6502::ill; 
-  *p++=&r6502::nop3; *p++=&r6502::and_ax; *p++=&r6502::rol_ax; *p++=&r6502::ill;
-  *p++=&r6502::rti; *p++=&r6502::eor_ix; *p++=&r6502::ill; *p++=&r6502::ill; 
-  *p++=&r6502::nop2; *p++=&r6502::eor_z; *p++=&r6502::lsr_z; *p++=&r6502::ill;
-  *p++=&r6502::pha; *p++=&r6502::eor_; *p++=&r6502::lsr_; *p++=&r6502::ill; 
-  *p++=&r6502::jmp; *p++=&r6502::eor_a; *p++=&r6502::lsr_a; *p++=&r6502::ill;
-  *p++=&r6502::bvc; *p++=&r6502::eor_iy; *p++=&r6502::ill; *p++=&r6502::ill; 
-  *p++=&r6502::nop2; *p++=&r6502::eor_zx; *p++=&r6502::lsr_zx; *p++=&r6502::ill;
-  *p++=&r6502::cli; *p++=&r6502::eor_ay; *p++=&r6502::nop; *p++=&r6502::ill; 
-  *p++=&r6502::nop3; *p++=&r6502::eor_ax; *p++=&r6502::lsr_ax; *p++=&r6502::ill;
-  *p++=&r6502::rts; *p++=&r6502::adc_ix; *p++=&r6502::ill; *p++=&r6502::ill; 
-  *p++=&r6502::nop2; *p++=&r6502::adc_z; *p++=&r6502::ror_z; *p++=&r6502::ill;
-  *p++=&r6502::pla; *p++=&r6502::adc_; *p++=&r6502::ror_; *p++=&r6502::ill; 
-  *p++=&r6502::jmp_i; *p++=&r6502::adc_a; *p++=&r6502::ror_a; *p++=&r6502::ill;
-  *p++=&r6502::bvs; *p++=&r6502::adc_iy; *p++=&r6502::ill; *p++=&r6502::ill; 
-  *p++=&r6502::nop2; *p++=&r6502::adc_zx; *p++=&r6502::ror_zx; *p++=&r6502::ill;
-  *p++=&r6502::sei; *p++=&r6502::adc_ay; *p++=&r6502::nop; *p++=&r6502::ill; 
-  *p++=&r6502::nop3; *p++=&r6502::adc_ax; *p++=&r6502::ror_ax; *p++=&r6502::ill;
-  *p++=&r6502::nop2; *p++=&r6502::sta_ix; *p++=&r6502::nop2; *p++=&r6502::ill; 
-  *p++=&r6502::sty_z; *p++=&r6502::sta_z; *p++=&r6502::stx_z; *p++=&r6502::ill;
-  *p++=&r6502::dey; *p++=&r6502::nop2; *p++=&r6502::txa; *p++=&r6502::ill; 
-  *p++=&r6502::sty_a; *p++=&r6502::sta_a; *p++=&r6502::stx_a; *p++=&r6502::ill;
-  *p++=&r6502::bcc; *p++=&r6502::sta_iy; *p++=&r6502::ill; *p++=&r6502::ill; 
-  *p++=&r6502::sty_zx; *p++=&r6502::sta_zx; *p++=&r6502::stx_zy; *p++=&r6502::ill;
-  *p++=&r6502::tya; *p++=&r6502::sta_ay; *p++=&r6502::txs; *p++=&r6502::ill; 
-  *p++=&r6502::ill; *p++=&r6502::sta_ax; *p++=&r6502::ill; *p++=&r6502::ill;
-  *p++=&r6502::ldy_; *p++=&r6502::lda_ix; *p++=&r6502::ldx_; *p++=&r6502::lax_ix; 
-  *p++=&r6502::ldy_z; *p++=&r6502::lda_z; *p++=&r6502::ldx_z; *p++=&r6502::lax_z;
-  *p++=&r6502::tay; *p++=&r6502::lda_; *p++=&r6502::tax; *p++=&r6502::ill; 
-  *p++=&r6502::ldy_a; *p++=&r6502::lda_a; *p++=&r6502::ldx_a; *p++=&r6502::lax_a;
-  *p++=&r6502::bcs; *p++=&r6502::lda_iy; *p++=&r6502::ill; *p++=&r6502::lax_iy; 
-  *p++=&r6502::ldy_zx; *p++=&r6502::lda_zx; *p++=&r6502::ldx_zy; *p++=&r6502::lax_zy;
-  *p++=&r6502::clv; *p++=&r6502::lda_ay; *p++=&r6502::tsx; *p++=&r6502::ill; 
-  *p++=&r6502::ldy_ax; *p++=&r6502::lda_ax; *p++=&r6502::ldx_ay; *p++=&r6502::lax_ay;
-  *p++=&r6502::cpy_; *p++=&r6502::cmp_ix; *p++=&r6502::nop2; *p++=&r6502::ill; 
-  *p++=&r6502::cpy_z; *p++=&r6502::cmp_z; *p++=&r6502::dec_z; *p++=&r6502::ill;
-  *p++=&r6502::iny; *p++=&r6502::cmp_; *p++=&r6502::dex; *p++=&r6502::ill; 
-  *p++=&r6502::cpy_a; *p++=&r6502::cmp_a; *p++=&r6502::dec_a; *p++=&r6502::ill;
-  *p++=&r6502::bne; *p++=&r6502::cmp_iy; *p++=&r6502::ill; *p++=&r6502::ill; 
-  *p++=&r6502::nop2; *p++=&r6502::cmp_zx; *p++=&r6502::dec_zx; *p++=&r6502::ill;
-  *p++=&r6502::cld; *p++=&r6502::cmp_ay; *p++=&r6502::nop; *p++=&r6502::ill; 
-  *p++=&r6502::nop3; *p++=&r6502::cmp_ax; *p++=&r6502::dec_ax; *p++=&r6502::ill;
-  *p++=&r6502::cpx_; *p++=&r6502::sbc_ix; *p++=&r6502::nop2; *p++=&r6502::ill; 
-  *p++=&r6502::cpx_z; *p++=&r6502::sbc_z; *p++=&r6502::inc_z; *p++=&r6502::ill;
-  *p++=&r6502::inx; *p++=&r6502::sbc_; *p++=&r6502::nop; *p++=&r6502::ill; 
-  *p++=&r6502::cpx_a; *p++=&r6502::sbc_a; *p++=&r6502::inc_a; *p++=&r6502::ill;
-  *p++=&r6502::beq; *p++=&r6502::sbc_iy; *p++=&r6502::ill; *p++=&r6502::ill; 
-  *p++=&r6502::nop2; *p++=&r6502::sbc_zx; *p++=&r6502::inc_zx; *p++=&r6502::ill;
-  *p++=&r6502::sed; *p++=&r6502::sbc_ay; *p++=&r6502::nop; *p++=&r6502::ill; 
-  *p++=&r6502::nop3; *p++=&r6502::sbc_ax; *p++=&r6502::inc_ax; *p++=&r6502::ill;
+	for (int i=0; i < 256; i++) {
+		_fromBCD[i] = ((i >> 4) & 0x0f)*10 + (i & 0x0f);
+		_toBCD[i] = (((i % 100) / 10) << 4) | (i % 10);
+	}
+		
+	OP *p = _ops;
+	*p++=&r6502::brk; *p++=&r6502::ora_ix; *p++=&r6502::ill; *p++=&r6502::ill; 
+	*p++=&r6502::nop2; *p++=&r6502::ora_z; *p++=&r6502::asl_z; *p++=&r6502::ill;
+	*p++=&r6502::php; *p++=&r6502::ora_; *p++=&r6502::asl; *p++=&r6502::ill; 
+	*p++=&r6502::nop3; *p++=&r6502::ora_a; *p++=&r6502::asl_a; *p++=&r6502::ill;
+	*p++=&r6502::bpl; *p++=&r6502::ora_iy; *p++=&r6502::ill; *p++=&r6502::ill; 
+	*p++=&r6502::nop2; *p++=&r6502::ora_zx; *p++=&r6502::asl_zx; *p++=&r6502::ill;
+	*p++=&r6502::clc; *p++=&r6502::ora_ay; *p++=&r6502::nop; *p++=&r6502::ill; 
+	*p++=&r6502::nop2; *p++=&r6502::ora_ax; *p++=&r6502::asl_ax; *p++=&r6502::ill;
+	*p++=&r6502::jsr; *p++=&r6502::and_ix; *p++=&r6502::ill; *p++=&r6502::ill; 
+	*p++=&r6502::bit_z; *p++=&r6502::and_z; *p++=&r6502::rol_z; *p++=&r6502::ill;
+	*p++=&r6502::plp; *p++=&r6502::and_; *p++=&r6502::rol; *p++=&r6502::ill; 
+	*p++=&r6502::bit_a; *p++=&r6502::and_a; *p++=&r6502::rol_a; *p++=&r6502::ill;
+	*p++=&r6502::bmi; *p++=&r6502::and_iy; *p++=&r6502::ill; *p++=&r6502::ill; 
+	*p++=&r6502::nop2; *p++=&r6502::and_zx; *p++=&r6502::rol_zx; *p++=&r6502::ill;
+	*p++=&r6502::sec; *p++=&r6502::and_ay; *p++=&r6502::nop; *p++=&r6502::ill; 
+	*p++=&r6502::nop3; *p++=&r6502::and_ax; *p++=&r6502::rol_ax; *p++=&r6502::ill;
+	*p++=&r6502::rti; *p++=&r6502::eor_ix; *p++=&r6502::ill; *p++=&r6502::ill; 
+	*p++=&r6502::nop2; *p++=&r6502::eor_z; *p++=&r6502::lsr_z; *p++=&r6502::ill;
+	*p++=&r6502::pha; *p++=&r6502::eor_; *p++=&r6502::lsr_; *p++=&r6502::ill; 
+	*p++=&r6502::jmp; *p++=&r6502::eor_a; *p++=&r6502::lsr_a; *p++=&r6502::ill;
+	*p++=&r6502::bvc; *p++=&r6502::eor_iy; *p++=&r6502::ill; *p++=&r6502::ill; 
+	*p++=&r6502::nop2; *p++=&r6502::eor_zx; *p++=&r6502::lsr_zx; *p++=&r6502::ill;
+	*p++=&r6502::cli; *p++=&r6502::eor_ay; *p++=&r6502::nop; *p++=&r6502::ill; 
+	*p++=&r6502::nop3; *p++=&r6502::eor_ax; *p++=&r6502::lsr_ax; *p++=&r6502::ill;
+	*p++=&r6502::rts; *p++=&r6502::adc_ix; *p++=&r6502::ill; *p++=&r6502::ill; 
+	*p++=&r6502::nop2; *p++=&r6502::adc_z; *p++=&r6502::ror_z; *p++=&r6502::ill;
+	*p++=&r6502::pla; *p++=&r6502::adc_; *p++=&r6502::ror_; *p++=&r6502::ill; 
+	*p++=&r6502::jmp_i; *p++=&r6502::adc_a; *p++=&r6502::ror_a; *p++=&r6502::ill;
+	*p++=&r6502::bvs; *p++=&r6502::adc_iy; *p++=&r6502::ill; *p++=&r6502::ill; 
+	*p++=&r6502::nop2; *p++=&r6502::adc_zx; *p++=&r6502::ror_zx; *p++=&r6502::ill;
+	*p++=&r6502::sei; *p++=&r6502::adc_ay; *p++=&r6502::nop; *p++=&r6502::ill; 
+	*p++=&r6502::nop3; *p++=&r6502::adc_ax; *p++=&r6502::ror_ax; *p++=&r6502::ill;
+	*p++=&r6502::nop2; *p++=&r6502::sta_ix; *p++=&r6502::nop2; *p++=&r6502::ill; 
+	*p++=&r6502::sty_z; *p++=&r6502::sta_z; *p++=&r6502::stx_z; *p++=&r6502::ill;
+	*p++=&r6502::dey; *p++=&r6502::nop2; *p++=&r6502::txa; *p++=&r6502::ill; 
+	*p++=&r6502::sty_a; *p++=&r6502::sta_a; *p++=&r6502::stx_a; *p++=&r6502::ill;
+	*p++=&r6502::bcc; *p++=&r6502::sta_iy; *p++=&r6502::ill; *p++=&r6502::ill; 
+	*p++=&r6502::sty_zx; *p++=&r6502::sta_zx; *p++=&r6502::stx_zy; *p++=&r6502::ill;
+	*p++=&r6502::tya; *p++=&r6502::sta_ay; *p++=&r6502::txs; *p++=&r6502::ill; 
+	*p++=&r6502::ill; *p++=&r6502::sta_ax; *p++=&r6502::ill; *p++=&r6502::ill;
+	*p++=&r6502::ldy_; *p++=&r6502::lda_ix; *p++=&r6502::ldx_; *p++=&r6502::lax_ix; 
+	*p++=&r6502::ldy_z; *p++=&r6502::lda_z; *p++=&r6502::ldx_z; *p++=&r6502::lax_z;
+	*p++=&r6502::tay; *p++=&r6502::lda_; *p++=&r6502::tax; *p++=&r6502::ill; 
+	*p++=&r6502::ldy_a; *p++=&r6502::lda_a; *p++=&r6502::ldx_a; *p++=&r6502::lax_a;
+	*p++=&r6502::bcs; *p++=&r6502::lda_iy; *p++=&r6502::ill; *p++=&r6502::lax_iy; 
+	*p++=&r6502::ldy_zx; *p++=&r6502::lda_zx; *p++=&r6502::ldx_zy; *p++=&r6502::lax_zy;
+	*p++=&r6502::clv; *p++=&r6502::lda_ay; *p++=&r6502::tsx; *p++=&r6502::ill; 
+	*p++=&r6502::ldy_ax; *p++=&r6502::lda_ax; *p++=&r6502::ldx_ay; *p++=&r6502::lax_ay;
+	*p++=&r6502::cpy_; *p++=&r6502::cmp_ix; *p++=&r6502::nop2; *p++=&r6502::ill; 
+	*p++=&r6502::cpy_z; *p++=&r6502::cmp_z; *p++=&r6502::dec_z; *p++=&r6502::ill;
+	*p++=&r6502::iny; *p++=&r6502::cmp_; *p++=&r6502::dex; *p++=&r6502::ill; 
+	*p++=&r6502::cpy_a; *p++=&r6502::cmp_a; *p++=&r6502::dec_a; *p++=&r6502::ill;
+	*p++=&r6502::bne; *p++=&r6502::cmp_iy; *p++=&r6502::ill; *p++=&r6502::ill; 
+	*p++=&r6502::nop2; *p++=&r6502::cmp_zx; *p++=&r6502::dec_zx; *p++=&r6502::ill;
+	*p++=&r6502::cld; *p++=&r6502::cmp_ay; *p++=&r6502::nop; *p++=&r6502::ill; 
+	*p++=&r6502::nop3; *p++=&r6502::cmp_ax; *p++=&r6502::dec_ax; *p++=&r6502::ill;
+	*p++=&r6502::cpx_; *p++=&r6502::sbc_ix; *p++=&r6502::nop2; *p++=&r6502::ill; 
+	*p++=&r6502::cpx_z; *p++=&r6502::sbc_z; *p++=&r6502::inc_z; *p++=&r6502::ill;
+	*p++=&r6502::inx; *p++=&r6502::sbc_; *p++=&r6502::nop; *p++=&r6502::ill; 
+	*p++=&r6502::cpx_a; *p++=&r6502::sbc_a; *p++=&r6502::inc_a; *p++=&r6502::ill;
+	*p++=&r6502::beq; *p++=&r6502::sbc_iy; *p++=&r6502::ill; *p++=&r6502::ill; 
+	*p++=&r6502::nop2; *p++=&r6502::sbc_zx; *p++=&r6502::inc_zx; *p++=&r6502::ill;
+	*p++=&r6502::sed; *p++=&r6502::sbc_ay; *p++=&r6502::nop; *p++=&r6502::ill; 
+	*p++=&r6502::nop3; *p++=&r6502::sbc_ax; *p++=&r6502::inc_ax; *p++=&r6502::ill;
 }
 
diff --git a/r6502.h b/r6502.h
index c74f6d0..10fa98c 100644
--- a/r6502.h
+++ b/r6502.h
@@ -8,6 +8,7 @@ class r6502: public CPU {
 public:
 	void raise(int);
 	void reset();
+	Memory::address step();
 	Memory::address run(unsigned);
 	char *status();
 	void checkpoint(Stream &);