Z80 bugfixes

Work-in-progress merging z80 fixes

src/CPU.h

@@ -3,17 +3,24 @@
 
 #undef PC
 
-#define O(o, e) case o: e(); break
-#define A(o, e, a) case o: e(a); break
-#define C(o) case o:
-#define D(e) default: e(); break
+#define E(op, expr)	case op: expr; break
+#define O(op, fn) 	E(op, fn())
+#define A(op, e, a) 	E(op, e(a))
+#define C(op) 		case op:
+#define D(fn) 		default: fn(); break
+
+#if defined(UNDOCUMENTED_OPS)
+#define U(op, expr)	case op: expr; break
+#else
+#define U(op, expr)
+#endif
 
 class CPU: public Checkpointable {
 public:
 	virtual ~CPU() {}
 	virtual void run(unsigned instructions) =0;
 	virtual void reset() =0;
-	virtual void raise(uint8_t level) =0;
+	virtual void raise(int level) =0;
 	virtual char *status(char *buf, size_t n, bool hdr = false) =0;
 
 	virtual void checkpoint(Stream &s) = 0;

src/i8080.cpp

@@ -24,7 +24,7 @@ void i8080::reset() {
 	_halted = false;
 }
 
-void i8080::raise(uint8_t level) {
+void i8080::raise(int level) {
 	if (flags.I) {
 		flags.I = 0;
 		_irq_pending = 0;

src/i8080.h

@@ -13,7 +13,7 @@ public:
 
 	void run(unsigned);
 	void reset();
-	void raise(uint8_t);
+	void raise(int);
 	char *status(char *buf, size_t n, bool hdr=false);
 
 	void checkpoint(Stream &);
@@ -59,7 +59,7 @@ private:
 		} flags;
 		uint8_t SR;
 	};
-	uint8_t _irq_pending;
+	int _irq_pending;
 	PortDevice &_ports;
 
 	void _op(uint8_t op);

src/r6502.cpp

@@ -76,7 +76,7 @@ void r6502::restore(Stream &s)
 #endif
 }
 
-void r6502::raise(uint8_t level) {
+void r6502::raise(int level) {
 	if (level < 0)
 		nmi();
 	else if (!P.bits.I)

src/r6502.h

@@ -7,7 +7,7 @@
 
 class r6502: public CPU {
 public:
-	void raise(uint8_t);
+	void raise(int);
 	void reset();
 	void run(unsigned);
 	char *status(char *buf, size_t n, bool hdr=false);

src/z80.cpp

@@ -8,13 +8,26 @@
 
 char *z80::status(char *buf, size_t n, bool hdr) {
 #if DEBUGGING & DEBUG_CPU
-	uint8_t op = _mem[PC];
+	static bool first = true;
 	snprintf(buf, n,
-		"%s%04x %02x %04x %04x %04x %04x %04x %04x %04x %04x %04x  %d%d%d "
-		"%04x %d%d%d%d%d%d%d%d",
-		hdr?  "_pc_ op _af_ _bc_ _de_ _hl_ _af' _bc' _de' _hl' _ir_ imff _sp_ sz5h3pnc\r\n": "",
-		PC, op, AF, BC, DE, HL, AF_, BC_, DE_, HL_, IR, _im, _iff1, _iff2,
-		SP, flags.S, flags.Z, flags._5, flags.H, flags._3, flags.P, flags.N, flags.C);
+		"%s%04x %02x %d%d%d%d%d%d %02x %02x %d%d  %04x %04x %04x %04x %04x %04x %04x %04x %04x %04x ",
+		hdr || first?  "PC   A  SZHPNC I  R  IFF BC   DE   HL   A'F' B'C' D'E' H'L' IX   IY   SP   OP\r\n": "",
+		PC, A, flags.S, flags.Z, flags.H, flags.P, flags.N, flags.C, I, R & 0x7f, _iff1, _iff2,
+		BC, DE, HL, AF_, BC_, DE_, HL_, IX, IY, SP);
+	first = false;
+
+	uint8_t op = _mem[PC], op1 = _mem[PC+1];
+	char obuf[16];
+	if (op == 0xdd || op == 0xfd) {
+		if (op1 == 0xcb)
+			snprintf(obuf, sizeof(obuf), "%02x cb %02x %02x", op, (byte)_mem[PC+2], (byte)_mem[PC+3]);
+		else
+			snprintf(obuf, sizeof(obuf), "%02x %02x", op, op1);
+	} else if (op == 0xed)
+		snprintf(obuf, sizeof(obuf), "ed %02x", op1);
+	else
+		snprintf(obuf, sizeof(obuf), "%02x", op);
+	strncat(buf, obuf, n);
 #endif
 	return buf;
 }
@@ -98,27 +111,47 @@ void z80::reset() {
 }
 
 void z80::_handle_interrupt() {
-	if (_irq_pending < 0 || _iff1) {
-		if (_halted) {
-			_halted = false;
-			PC++;
-		}
-		_push(PC);
-		if (_irq_pending < 0) {	// NMI
-			_iff2 = _iff1;
-			PC = 0x0066;
-			ts(11);
-		} else {
-			_iff1 = _iff2 = false;
-			R++;
-			if (_im == 0 || _im == 1)
-				PC = 0x0038;
-			else if (_im == 2)
-				PC = _rw(_irq_pending + (0x100 * I));
-			ts(7);
-		}
-	}
+
+	int irq = _irq_pending;
 	_irq_pending = 0;
+
+	if (!irq && !_iff1) {
+		DBG_CPU(println("No interrupt!"));
+		return;
+	}
+
+	if (_halted) {
+		_halted = false;
+		PC++;
+	}
+	_push(PC);
+	if (irq < 0) {	// NMI
+		DBG_CPU(println("NMI"));
+		_iff2 = _iff1;
+		PC = 0x66;
+		ts(11);
+		return;
+	}
+	_iff1 = _iff2 = false;
+	R++;
+	if (_im == 0)
+		switch (irq) {
+		case 0xc7: PC = 0x00; break;
+		case 0xcf: PC = 0x08; break;
+		case 0xd7: PC = 0x10; break;
+		case 0xdf: PC = 0x18; break;
+		case 0xe7: PC = 0x20; break;
+		case 0xef: PC = 0x28; break;
+		case 0xf7: PC = 0x30; break;
+		case 0xff: PC = 0x38; break;
+		}
+	else if (_im == 1)
+		PC = 0x38;
+	else if (_im == 2)
+		PC = _rw(irq + (0x100 * I));
+	ts(7);
+
+	DBG_CPU(printf("IM: %d PC: %04x\r\n", _im, PC));
 }
 
 void z80::daa() {
@@ -154,272 +187,129 @@ void z80::_step_idx(EXT_OP f) {
 }
 
 void z80::_ddfd(uint16_t &ix, uint8_t &ixL, uint8_t &ixH, EXT_OP op) {
-	switch (_fetch_op()) {
-	case 0x09:
-		_add16(ix, BC);
-		break;
-	case 0x19:
-		_add16(ix, DE);
-		break;
-	case 0x21:
-		ix = _rwpc();
-		break;
-	case 0x22:
-		_swPC(ix);
-		break;
-	case 0x23:
-		ix++;
-		_mc(IR, 1); _mc(IR, 1);
-		break;
-	case 0x24:
-		_inc(ixH);
-		break;
-	case 0x25:
-		_dec(ixH);
-		break;
-	case 0x26:
-		ixH = _rb(PC++);
-		break;
-	case 0x29:
-		_add16(ix, ix);
-		break;
-	case 0x2a:
-		ix = _rwPC();
-		break;
-	case 0x2b:
-		ix--;
-		_mc(IR, 1); _mc(IR, 1);
-		break;
-	case 0x2c:
-		_inc(ixL);
-		break;
-	case 0x2d:
-		_dec(ixL);
-		break;
-	case 0x2e:
-		ixL = _rb(PC++);
-		break;
-	case 0x34:
-		_incO(ix);
-		break;
-	case 0x35:
-		_decO(ix);
-		break;
-	case 0x36:
-		_sbO(ix);
-		break;
-	case 0x39:
-		_add16(ix, SP);
-		break;
-	case 0x44:
-		B = ixH;
-		break;
-	case 0x45:
-		B = ixL;
-		break;
-	case 0x46:
-		B = _rbO(ix);
-		break;
-	case 0x4c:
-		C = ixH;
-		break;
-	case 0x4d:
-		C = ixL;
-		break;
-	case 0x4e:
-		C = _rbO(ix);
-		break;
-	case 0x54:
-		D = ixH;
-		break;
-	case 0x55:
-		D = ixL;
-		break;
-	case 0x56:
-		D = _rbO(ix);
-		break;
-	case 0x5c:
-		E = ixH;
-		break;
-	case 0x5d:
-		E = ixL;
-		break;
-	case 0x5e:
-		E = _rbO(ix);
-		break;
-	case 0x60:
-		ixH = B;
-		break;
-	case 0x61:
-		ixH = C;
-		break;
-	case 0x62:
-		ixH = D;
-		break;
-	case 0x63:
-		ixH = E;
-		break;
-	case 0x64:
-		break;
-	case 0x65:
-		ixH = ixL;
-		break;
-	case 0x66:
-		H = _rbO(ix);
-		break;
-	case 0x67:
-		ixH = A;
-		break;
-	case 0x68:
-		ixL = B;
-		break;
-	case 0x69:
-		ixL = C;
-		break;
-	case 0x6a:
-		ixL = D;
-		break;
-	case 0x6b:
-		ixL = E;
-		break;
-	case 0x6c:
-		ixL = ixH;
-		break;
-	case 0x6d:
-		break;
-	case 0x6e:
-		L = _rbO(ix);
-		break;
-	case 0x6f:
-		ixL = A;
-		break;
-	case 0x70:
-		_sbO(ix, B);
-		break;
-	case 0x71:
-		_sbO(ix, C);
-		break;
-	case 0x72:
-		_sbO(ix, D);
-		break;
-	case 0x73:
-		_sbO(ix, E);
-		break;
-	case 0x74:
-		_sbO(ix, H);
-		break;
-	case 0x75:
-		_sbO(ix, L);
-		break;
-	case 0x77:
-		_sbO(ix, A);
-		break;
-	case 0x7c:
-		A = ixH;
-		break;
-	case 0x7d:
-		A = ixL;
-		break;
-	case 0x7e:
-		A = _rbO(ix);
-		break;
-	case 0x84:
-		_add(ixH);
-		break;
-	case 0x85:
-		_add(ixL);
-		break;
-	case 0x86:
-		_add(_rbO(ix));
-		break;
-	case 0x8c:
-		_adc(ixH);
-		break;
-	case 0x8d:
-		_adc(ixL);
-		break;
-	case 0x8e:
-		_adc(_rbO(ix));
-		break;
-	case 0x94:
-		_sub(ixH);
-		break;
-	case 0x95:
-		_sub(ixL);
-		break;
-	case 0x96:
-		_sub(_rbO(ix));
-		break;
-	case 0x9c:
-		_sbc(ixH);
-		break;
-	case 0x9d:
-		_sbc(ixL);
-		break;
-	case 0x9e:
-		_sbc(_rbO(ix));
-		break;
-	case 0xa4:
-		_and(ixH);
-		break;
-	case 0xa5:
-		_and(ixL);
-		break;
-	case 0xa6:
-		_and(_rbO(ix));
-		break;
-	case 0xac:
-		_xor(ixH);
-		break;
-	case 0xad:
-		_xor(ixL);
-		break;
-	case 0xae:
-		_xor(_rbO(ix));
-		break;
-	case 0xb4:
-		_or(ixH);
-		break;
-	case 0xb5:
-		_or(ixL);
-		break;
-	case 0xb6:
-		_or(_rbO(ix));
-		break;
-	case 0xbc:
-		_cmp(ixH);
-		break;
-	case 0xbd:
-		_cmp(ixL);
-		break;
-	case 0xbe:
-		_cmp(_rbO(ix));
-		break;
-	case 0xcb:
-		_step_idx(op);
-		break;
-	case 0xe1:
-		ix = _pop();
-		break;
-	case 0xe3:
-		_exSP(ix);
-		break;
-	case 0xe5:
-		_mc(IR, 1);
-		_push(ix);
-		break;
-	case 0xe9:
-		PC = ix;
-		break;
-	case 0xf9:
-		_mc(IR, 1); _mc(IR, 1);
-		SP = ix;
-		break;
+
+	uint8_t o = _fetch_op();
+	switch (o) {
+	E(0x09, _add16(ix, BC));
+	E(0x19, _add16(ix, DE));
+
+	E(0x21, ix = _rwpc());
+	E(0x22, _swPC(ix));
+	E(0x23, ix++; _mc(IR, 1); _mc(IR, 1));
+
+	U(0x24, _inc(ixH));
+	U(0x25, _dec(ixH));
+	U(0x26, ixH = _rb(PC++));
+
+	E(0x29, _add16(ix, ix));
+	E(0x2a, ix = _rwPC());
+	E(0x2b, ix--; _mc(IR, 1); _mc(IR, 1));
+
+	U(0x2c, _inc(ixL));
+	U(0x2d, _dec(ixL));
+	U(0x2e, ixL = _rb(PC++));
+
+	E(0x34, _incO(ix));
+	E(0x35, _decO(ix));
+	E(0x36, _sbO(ix));
+
+	E(0x39, _add16(ix, SP));
+
+	U(0x44, B = ixH);
+	U(0x45, B = ixL);
+	E(0x46, B = _rbO(ix));
+
+	U(0x4c, C = ixH);
+	U(0x4d, C = ixL);
+	E(0x4e, C = _rbO(ix));
+
+	U(0x54, D = ixH);
+	U(0x55, D = ixL);
+	E(0x56, D = _rbO(ix));
+
+	U(0x5c, E = ixH);
+	U(0x5d, E = ixL);
+	E(0x5e, E = _rbO(ix));
+
+	U(0x60, ixH = B);
+	U(0x61, ixH = C);
+	U(0x62, ixH = D);
+	U(0x63, ixH = E);
+	U(0x64, /* FIXME */);
+	U(0x65, ixH = ixL);
+	E(0x66, H = _rbO(ix));
+	U(0x67, ixH = A);
+	U(0x68, ixL = B);
+	U(0x69, ixL = C);
+	U(0x6a, ixL = D);
+	U(0x6b, ixL = E);
+	U(0x6c, ixL = ixH);
+	U(0x6d, /* FIXME */);
+	E(0x6e, L = _rbO(ix));
+	U(0x6f, ixL = A);
+	E(0x70, _sbO(ix, B));
+	E(0x71, _sbO(ix, C));
+	E(0x72, _sbO(ix, D));
+	E(0x73, _sbO(ix, E));
+	E(0x74, _sbO(ix, H));
+	E(0x75, _sbO(ix, L));
+
+	E(0x77, _sbO(ix, A));
+
+	U(0x7c, A = ixH);
+	U(0x7d, A = ixL);
+	E(0x7e, A = _rbO(ix));
+
+	U(0x84, _add(ixH));
+	U(0x85, _add(ixL));
+	E(0x86, _add(_rbO(ix)));
+
+	U(0x8c, _adc(ixH));
+	U(0x8d, _adc(ixL));
+	E(0x8e, _adc(_rbO(ix)));
+
+	U(0x94, _sub(ixH));
+	U(0x95, _sub(ixL));
+	E(0x96, _sub(_rbO(ix)));
+
+	U(0x9c, _sbc(ixH));
+	U(0x9d, _sbc(ixL));
+	E(0x9e, _sbc(_rbO(ix)));
+
+	U(0xa4, _and(ixH));
+	U(0xa5, _and(ixL));
+	E(0xa6, _and(_rbO(ix)));
+
+	U(0xac, _xor(ixH));
+	U(0xad, _xor(ixL));
+	E(0xae, _xor(_rbO(ix)));
+
+	U(0xb4, _or(ixH));
+	U(0xb5, _or(ixL));
+	E(0xb6, _or(_rbO(ix)));
+
+	U(0xbc, _cmp(ixH));
+	U(0xbd, _cmp(ixL));
+	E(0xbe, _cmp(_rbO(ix)));
+
+	E(0xcb, _step_idx(op));
+
+	E(0xe1, ix = _pop());
+	E(0xe3, _exSP(ix));
+	E(0xe5, _mc(IR, 1); _push(ix));
+	E(0xe9, PC = ix);
+
+	E(0xf9, _mc(IR, 1); _mc(IR, 1); SP = ix);
+
+	default:
+		ERR(printf("unimplemented dd/fd op: %02x\r\n", o));
 	}
 }
 
 void z80::ed() {
-	switch (_fetch_op()) {
+
+	uint8_t op = _fetch_op();
+	switch (op) {
 	O(0x40, inB);
 	O(0x41, outB);
 	O(0x42, sbcBC);
@@ -507,6 +397,9 @@ void z80::ed() {
 	O(0xb9, cpdr);
 	O(0xba, indr);
 	O(0xbb, outdr);
+
+	default:
+		ERR(printf("unimplemented ed op: %02x\r\n", op));
 	}
 }
 

src/z80.h

@@ -11,7 +11,7 @@ public:
 
 	void run(unsigned);
 	void reset();
-	void raise(uint8_t level) { _irq_pending = level; }
+	void raise(int level) { _irq_pending = level; }
 	char *status(char *buf, size_t n, bool hdr=false);
 
 	void checkpoint(Stream &);
@@ -145,7 +145,7 @@ private:
 
 	unsigned long _ts;
 
-	uint8_t _irq_pending;
+	int _irq_pending;
 	PortDevice &_ports;
 
 	uint8_t parity(uint8_t);
@@ -403,7 +403,11 @@ private:
 	inline void incb() { _inc(B); }
 	inline void decb() { _dec(B); }
 	inline void ldb() { B = _rb(PC++); }
-	inline void rlca() { flags.C = ((A & 0x80) >> 7); A = (A << 1) | flags.C; }
+	inline void rlca() {
+		flags.H = flags.N = 0;
+		flags.C = ((A & 0x80) >> 7);
+		A = (A << 1) | flags.C;
+	}
 
 	// 0x08
 	inline void exaf() { _exch(AF, AF_); }
@@ -431,6 +435,7 @@ private:
 	inline void rla() {
 		uint8_t b = (A << 1) | flags.C;
 		flags.C = (A & 0x80) >> 7;
+		flags.H = flags.N = 0;
 		A = b;
 	}
 
@@ -449,6 +454,7 @@ private:
 	inline void rra() {
 		uint8_t b = (A >> 1) | (flags.C << 7);
 		flags.C = (A & 1);
+		flags.H = flags.N = 0;
 		A = b;
 	}
 
@@ -490,7 +496,17 @@ private:
 	inline void inca() { _inc(A); }
 	inline void deca() { _dec(A); }
 	inline void lda() { A = _rb(PC++); }
-	inline void ccf() { flags.H = flags.C; flags.C = flags.N = 0; _35(A); }
+	inline void ccf() {
+		if (flags.C) {
+			flags.C = 0;
+			flags.H = 1;
+		} else {
+			flags.H = 0;
+			flags.C = 1;
+		}
+		flags.N = 0;
+		_35(A);
+	}
 
 	// 0x40
 	inline void ldbb() {}
@@ -1271,19 +1287,15 @@ private:
 	}
 	inline void cpi() {
 		uint8_t b = _rb(HL);
+		flags.H = ((b & 0x0f) > (A & 0x0f));
+		b = A - b;
 		_mc(HL, 1); _mc(HL, 1); _mc(HL, 1);
 		_mc(HL, 1); _mc(HL, 1);
-		uint8_t c = A;
-		uint8_t f = (flags.C != 0);
-		_sub(b);
 		HL++;
 		BC--;
-		b = A;
-		A = c;
-		if (flags.H) b--;
-		flags.C = f;
+		flags.N = 1;
 		flags.P = (BC != 0);
-		_35(b);
+		_sz35(b);
 		flags._5 = ((b & 0x02) != 0);
 		_memptr++;
 	}
@@ -1327,17 +1339,17 @@ private:
 	}
 	inline void cpd_() {
 		uint8_t b = _rb(HL);
-		uint8_t c = A - b - flags.H;
+		flags.H = ((b & 0x0f) > (A & 0x0f));
+		b = A - b;
 		_mc(HL, 1); _mc(HL, 1); _mc(HL, 1);
 		_mc(HL, 1); _mc(HL, 1);
 		HL--;
 		BC--;
 		flags.N = 1;
 		flags.P = (BC != 0);
-		_sz35(c);
-		flags._5 = ((c & 0x02) != 0);
+		_sz35(b);
+		flags._5 = ((b & 0x02) != 0);
 		_memptr--;
-		// FIXME: flag H
 	}
 	inline void ind() {
 		_mc(IR, 1);
@@ -1366,48 +1378,33 @@ private:
 		_sz35(B);
 	}
 	inline void ldir() {
-		uint8_t b = _rb(HL);
-		BC--;
-		_sb(DE, b);
-		_mc(DE, 1);
-		_mc(DE, 1);
+		uint8_t b;
+		do {
+			b = _rb(HL);
+			_sb(DE, b);
+			_mc(DE, 1);
+			_mc(DE, 1);
+			DE++;
+			HL++;
+		} while (--BC);
 		b += A;
-		flags.P = (BC != 0);
 		_35(b);
 		flags._5 = ((b & 0x02) != 0);
-		flags.N = flags.H = 0;
-		if (BC) {
-			_mc(DE, 1); _mc(DE, 1); _mc(DE, 1);
-			_mc(DE, 1); _mc(DE, 1);
-			PC -= 2;
-			_memptr = PC+1;
-		}
-		DE++;
-		HL++;
+		flags.N = flags.P = flags.H = 0;
 	}
 	inline void cpir() {
-		uint8_t b = _rb(HL);
-		_mc(HL, 1); _mc(HL, 1); _mc(HL, 1);
-		_mc(HL, 1); _mc(HL, 1);
-		uint8_t c = A;
-		uint8_t f = (flags.C != 0);
-		_sub(b);
-		BC--;
-		b -= A;
-		A = c;
-		flags.C = f;
-		flags.P = (BC != 0);
-		if (flags.H) b--;
-		_35(b);
-		flags._5 = ((b & 0x02) != 0);
-		_memptr++;
-		if (!flags.Z) {
+		uint8_t d;
+		do {
+			uint8_t b = _rb(HL++);
 			_mc(HL, 1); _mc(HL, 1); _mc(HL, 1);
 			_mc(HL, 1); _mc(HL, 1);
-			PC -= 2;
-			_memptr = PC+1;
-		}
-		HL++;
+			flags.H = ((b & 0x0f) > (A & 0xf));
+			d = A - b;
+		} while (--BC && d);
+		flags.N = 1;
+		flags.P = (BC != 0);
+		_sz35(d);
+		flags._5 = ((d & 0x02) != 0);
 	}
 	inline void inir() {
 		_mc(IR, 1);
@@ -1444,44 +1441,33 @@ private:
 		}
 	}
 	inline void lddr() {
-		uint8_t b = _rb(HL);
-		BC--;
-		_sb(DE, b);
-		_mc(DE, 1);
-		_mc(DE, 1);
+		uint8_t b;
+		do {
+			b = _rb(HL);
+			_sb(DE, b);
+			_mc(DE, 1);
+			_mc(DE, 1);
+			DE--;
+			HL--;
+		} while (--BC);
 		b += A;
-		flags.P = (BC != 0);
 		_35(b);
 		flags._5 = ((b & 0x02) != 0);
-		flags.N = flags.H = 0;
-		if (BC) {
-			_mc(DE, 1); _mc(DE, 1); _mc(DE, 1);
-			_mc(DE, 1); _mc(DE, 1);
-			PC -= 2;
-			_memptr = PC+1;
-		}
-		DE--;
-		HL--;
+		flags.N = flags.H = flags.P = 0;
 	}
 	inline void cpdr() {
-		uint8_t b = _rb(HL);
-		uint8_t c = A - b;
-		_mc(HL, 1); _mc(HL, 1); _mc(HL, 1);
-		_mc(HL, 1); _mc(HL, 1);
-		BC--;
-		flags.N = 1;
-		flags.P = (BC != 0);
-		_sz35(c);
-		flags._5 = ((c & 0x02) != 0);
-		// FIXME: flag H
-		_memptr--;
-		if (BC) {
+		uint8_t d;
+		do {
+			uint8_t b = _rb(HL--);
 			_mc(HL, 1); _mc(HL, 1); _mc(HL, 1);
 			_mc(HL, 1); _mc(HL, 1);
-			PC -= 2;
-			_memptr = PC+1;
-		}
-		HL--;
+			flags.H = ((b & 0x0f) > (A & 0xf));
+			d = A - b;
+		} while (--BC && d);
+		flags.N = 1;
+		flags.P = (BC != 0);
+		_sz35(d);
+		flags._5 = ((d & 0x02) != 0);
 	}
 	inline void indr() {
 		_mc(IR, 1);
@@ -1519,8 +1505,8 @@ private:
 			PC -= 2;
 		}
 	}
-	// 0xDDCB extended instructions
 
+	// 0xDDCB extended instructions
 	inline uint16_t _rbIX(uint8_t &b, uint8_t o) {
 		uint16_t a = _ads(IX, o);
 		_memptr = a;