m6502: Return to implicitly using read_arg to read operands at PC (fi…

…xes regression in all XaviX games)

Side note: this changes the semantics of read_pc to what was formerly known as read_pc_noinc. Now that memory accesses themselves can be interrupted and restarted, updating PC as a side effect is obsolete anyway.

src/devices/cpu/m6502/m6502.h

@@ -144,8 +144,7 @@ class m6502_device : public cpu_device {
 	void write(uint16_t adr, uint8_t val) { mintf->write(adr, val); }
 	void write_9(uint16_t adr, uint8_t val) { mintf->write_9(adr, val); }
 	uint8_t read_arg(uint16_t adr) { return mintf->read_arg(adr); }
-	uint8_t read_pc() { return mintf->read_arg(PC++); }
-	uint8_t read_pc_noinc() { return mintf->read_arg(PC); }
+	uint8_t read_pc() { return mintf->read_arg(PC); }
 	void prefetch_start();
 	void prefetch_end();
 	void prefetch_end_noirq();

src/devices/cpu/m6502/odeco16.lst

@@ -4,9 +4,9 @@
 brk_16_imp
 	// The 6502 bug when a nmi occurs in a brk is reproduced (case !irq_taken && nmi_pending)
 	if(irq_taken) {
-		read(PC);
+		read_pc();
 	} else {
-		read(PC);
+		read_pc();
 		PC++;
 	}
 	write(SP, PC >> 8);
@@ -36,70 +36,70 @@ ill_non
 	prefetch();
 
 u0B_zpg
-	TMP2 = read(PC);
+	TMP2 = read_pc();
 	PC++;
 	if(DECO16_VERBOSE)
 		logerror("%s: OP0B %02x (%04x)\n", tag(), NPC, TMP2);
 	prefetch();
 
 u13_zpg
-	TMP2 = read(PC);
+	TMP2 = read_pc();
 	PC++;
 	if(DECO16_VERBOSE)
 		logerror("%s: OP13 %02x (%04x)\n", tag(), NPC, TMP2);
 	prefetch();
 
 u23_zpg
-	TMP2 = read(PC);
+	TMP2 = read_pc();
 	PC++;
 	if(DECO16_VERBOSE)
 		logerror("%s: OP23 %02x (%04x)\n", tag(), NPC, TMP2);
 	prefetch();
 
 u3F_zpg
-	TMP2 = read(PC);
+	TMP2 = read_pc();
 	PC++;
 	if(DECO16_VERBOSE)
 		logerror("%s: OPBB %02x (%04x)\n", tag(), NPC, TMP2);
 	prefetch();
 
 u4B_zpg
-	TMP2 = read(PC);
+	TMP2 = read_pc();
 	PC++;
 	A = io->read_byte(1);
 	prefetch();
 
 u87_zpg
-	TMP2 = read(PC);
+	TMP2 = read_pc();
 	PC++;
 	if(DECO16_VERBOSE)
 		logerror("%s: OP87 %02x (%04x)\n", tag(), NPC, TMP2);
 	prefetch();
 
 u8F_zpg
-	TMP2 = read(PC);
+	TMP2 = read_pc();
 	PC++;
 	if(DECO16_VERBOSE)
 		logerror("%s: OP8F (BANK) %02x (%04x)\n", tag(), NPC, TMP2);
 	io->write_byte(0, TMP2);
 	prefetch();
 
 uA3_zpg
-	TMP2 = read(PC);
+	TMP2 = read_pc();
 	PC++;
 	if(DECO16_VERBOSE)
 		logerror("%s: OPA3 %02x (%04x)\n", tag(), NPC, TMP2);
 	prefetch();
 
 uBB_zpg
-	TMP2 = read(PC);
+	TMP2 = read_pc();
 	PC++;
 	if(DECO16_VERBOSE)
 		logerror("%s: OPBB %02x (%04x)\n", tag(), NPC, TMP2);
 	prefetch();
 
 vbl_zpg
-	TMP2 = read(PC);
+	TMP2 = read_pc();
 	PC++;
 	A = io->read_byte(0);
 	//if(DECO16_VERBOSE)