Added six instructions for transfering data

between the three main registers.

These instructions are:
TAY: Transfer Accumulator to Y.
TAX: Transfer Accumulator to X.
TYX: Transfer Y to X.
TYA: Transfer Y to Accumulator.
TXA: Transfer X to Accumulator.
TXY: Transfer X to Y.

1 files changed, 12 insertions, 0 deletions

diff --git a/opcode.h b/opcode.h
index 1f84763..ae637d4 100644
--- a/opcode.h
+++ b/opcode.h
@@ -9,13 +9,19 @@
 #define PHP 0x08 /* PusH Processor status to stack. */
 #define PHA 0x09 /* PusH Accumulator to stack. */
 #define PHY 0x0A /* PusH Y register to stack. */
+#define TAY 0x0B /* Transfer Accumulator to Y. */
 #define PHX 0x0C /* PusH X register to stack. */
+#define TAX 0x0D /* Transfer Accumulator to X. */
+#define TYX 0x0E /* Transfer Y to X. */
 #define JMP 0x10 /* JuMP to memory location. */
 #define SBC 0x11 /* SuBtract with Carry. */
 #define PLP 0x18 /* PuLl Processor status from stack. */
 #define PLA 0x19 /* PuLl Accumulator from stack. */
 #define PLY 0x1A /* PuLl Y register from stack. */
+#define TYA 0x1B /* Transfer Y to Accumulator. */
 #define PLX 0x1C /* PuLl X register from stack. */
+#define TXA 0x1D /* Transfer X to Accumulator. */
+#define TXY 0x1E /* Transfer X to Y. */
 #define JSR 0x20 /* Jump to SubRoutine. */
 #define AND 0x21 /* bitwise AND with accumulator. */
 #define ANY 0x22 /* bitwise ANd with Y register.*/
@@ -126,7 +132,10 @@ static const char *opname[0x100] = {
 	OPNAME(PHP),
 	OPNAME(PHA),
 	OPNAME(PHY),
+	OPNAME(TAY),
 	OPNAME(PHX),
+	OPNAME(TAX),
+	OPNAME(TYX),
 	OPNAME(JMP),
 	[SBC] = "SBC #",
 	[0x13] = "SBC a",
@@ -134,7 +143,10 @@ static const char *opname[0x100] = {
 	OPNAME(PLP),
 	OPNAME(PLA),
 	OPNAME(PLY),
+	OPNAME(TYA),
 	OPNAME(PLX),
+	OPNAME(TXA),
+	OPNAME(TXY),
 	OPNAME(JSR),
 	[AND] = "AND #",
 	[ANY] = "ANY #",