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.

4 files changed, 151 insertions, 79 deletions

diff --git a/asmmon.c b/asmmon.c
index 587b1f6..73697d1 100644
--- a/asmmon.c
+++ b/asmmon.c
@@ -3,6 +3,7 @@
 
 #define debug 1
 
+#define OPNUM 85
 #define SETOP(num, _mne, _IMM, _ZM, _ZMX, _ZMY, _ABS, _IMPL) \
 {opcodes[num].mnemonic[3] = '\0'; strncpy(opcodes[num].mnemonic, _mne, 3); \
 opcodes[num].imm = _IMM; \
@@ -10,87 +11,93 @@ opcodes[num].zm = _ZM; opcodes[num].zmx = _ZMX; opcodes[num].zmy = _ZMY; \
 opcodes[num].abs = _ABS; opcodes[num].impl = _IMPL;}
 
 int asmmon() {
-	opent opcodes[79];
+	opent opcodes[OPNUM];
 	/*	  mne	 IMM	ZM   ZMX   ZMY	 ABS  IMPL*/
 	SETOP(0, "CPS", 0x00, 0x00, 0x00, 0x00, 0x00, 0x00);
 	SETOP(1, "ADC", 0x01, 0x05, 0x00, 0x00, 0x03, 0x00);
 	SETOP(2, "PHP", 0x08, 0x00, 0x00, 0x00, 0x00, 0x00);
 	SETOP(3, "PHA", 0x09, 0x00, 0x00, 0x00, 0x00, 0x00);
 	SETOP(4, "PHY", 0x0A, 0x00, 0x00, 0x00, 0x00, 0x00);
-	SETOP(5, "PHX", 0x0C, 0x00, 0x00, 0x00, 0x00, 0x00);
-	SETOP(6, "JMP", 0x00, 0xD0, 0x00, 0x00, 0x10, 0x00);
-	SETOP(7, "SBC", 0x11, 0x15, 0x00, 0x00, 0x13, 0x00);
-	SETOP(8, "PLP", 0x18, 0x00, 0x00, 0x00, 0x00, 0x00);
-	SETOP(9, "PLA", 0x19, 0x00, 0x00, 0x00, 0x00, 0x00);
-	SETOP(10, "PLY", 0x1A, 0x00, 0x00, 0x00, 0x00, 0x00);
-	SETOP(11, "PLX", 0x1C, 0x00, 0x00, 0x00, 0x00, 0x00);
-	SETOP(12, "JSR", 0x00, 0x20, 0x00, 0x00, 0x00, 0x00);
-	SETOP(13, "AND", 0x21, 0x2B, 0x00, 0x00, 0x29, 0x00);
-	SETOP(14, "ANY", 0x22, 0x82, 0x00, 0x00, 0x52, 0x00);
-	SETOP(15, "AAY", 0x00, 0x00, 0x00, 0x00, 0x00, 0x23);
-	SETOP(16, "ANX", 0x24, 0x84, 0x00, 0x00, 0x54, 0x00);
-	SETOP(17, "AAX", 0x00, 0x00, 0x00, 0x00, 0x00, 0x25);
-	SETOP(18, "STT", 0x28, 0x00, 0x00, 0x00, 0x00, 0x00);
-	SETOP(19, "BPO", 0x00, 0x00, 0x00, 0x00, 0x30, 0x00);
-	SETOP(20, "ORA", 0x31, 0x3B, 0x00, 0x00, 0x39, 0x00);
-	SETOP(21, "ORY", 0x32, 0x00, 0x00, 0x00, 0x62, 0x00);
-	SETOP(22, "OAY", 0x00, 0x00, 0x00, 0x00, 0x00, 0x33);
-	SETOP(23, "ORX", 0x34, 0x94, 0x00, 0x00, 0x64, 0x00);
-	SETOP(24, "OAX", 0x00, 0x00, 0x00, 0x00, 0x00, 0x35);
-	SETOP(25, "SEI", 0x00, 0x00, 0x00, 0x00, 0x00, 0x38);
-	SETOP(26, "BNG", 0x00, 0x00, 0x00, 0x00, 0x40, 0x00);
-	SETOP(27, "XOR", 0x41, 0x4B, 0x00, 0x00, 0x49, 0x00);
-	SETOP(28, "XRY", 0x42, 0xA2, 0x00, 0x00, 0x72, 0x00);
-	SETOP(29, "XAY", 0x00, 0x00, 0x00, 0x00, 0x00, 0x43);
-	SETOP(30, "XRX", 0x44, 0xA4, 0x00, 0x00, 0x74, 0x00);
-	SETOP(31, "XAX", 0x00, 0x00, 0x00, 0x00, 0x00, 0x45);
-	SETOP(32, "CLI", 0x00, 0x00, 0x00, 0x00, 0x00, 0x48);
-	SETOP(33, "BCS", 0x00, 0x00, 0x00, 0x00, 0x50, 0x00);
-	SETOP(34, "LSL", 0x51, 0x55, 0x00, 0x00, 0x53, 0x00);
-	SETOP(35, "SEC", 0x00, 0x00, 0x00, 0x00, 0x00, 0x58);
-	SETOP(36, "STA", 0x00, 0x7B, 0x8B, 0x9B, 0x5B, 0x00);
-	SETOP(37, "STY", 0x00, 0x7D, 0x8D, 0x00, 0x5D, 0x00);
-	SETOP(38, "STX", 0x00, 0x7E, 0x00, 0x9E, 0x5E, 0x00);
-	SETOP(39, "BCC", 0x00, 0x00, 0x00, 0x00, 0x60, 0x00);
-	SETOP(40, "LSR", 0x61, 0x65, 0x00, 0x00, 0x63, 0x00);
-	SETOP(41, "CLC", 0x00, 0x00, 0x00, 0x00, 0x00, 0x68);
-	SETOP(42, "LDA", 0x69, 0x79, 0x89, 0x99, 0x59, 0x00);
-	SETOP(43, "LDY", 0x6A, 0x7A, 0x8A, 0x00, 0x5A, 0x00);
-	SETOP(44, "LDX", 0x6C, 0x7C, 0x00, 0x9C, 0x5C, 0x00);
-	SETOP(45, "BEQ", 0x00, 0x00, 0x00, 0x00, 0x70, 0x00);
-	SETOP(46, "ROL", 0x71, 0x75, 0x00, 0x00, 0x73, 0x00);
-	SETOP(47, "SSP", 0x00, 0x00, 0x00, 0x00, 0x00, 0x78);
-	SETOP(48, "BNE", 0x00, 0x00, 0x00, 0x00, 0x80, 0x00);
-	SETOP(49, "ROR", 0x81, 0x85, 0x00, 0x00, 0x83, 0x00);
-	SETOP(50, "CSP", 0x00, 0x00, 0x00, 0x00, 0x00, 0x88);
-	SETOP(51, "BVS", 0x00, 0x00, 0x00, 0x00, 0x90, 0x00);
-	SETOP(52, "MUL", 0x91, 0x95, 0x00, 0x00, 0x93, 0x00);
-	SETOP(53, "SEV", 0x00, 0x00, 0x00, 0x00, 0x00, 0x98);
-	SETOP(54, "BVC", 0x00, 0x00, 0x00, 0x00, 0xA0, 0x00);
-	SETOP(55, "DIV", 0xA1, 0xA5, 0x00, 0x00, 0xA3, 0x00);
-	SETOP(56, "CLV", 0x00, 0x00, 0x00, 0x00, 0x00, 0xA8);
-	SETOP(57, "RTS", 0x00, 0x00, 0x00, 0x00, 0x00, 0xB0);
-	SETOP(58, "CMP", 0xB1, 0xF5, 0x00, 0x00, 0xE5, 0x00);
-	SETOP(59, "CPY", 0xB2, 0xF2, 0x00, 0x00, 0xE2, 0x00);
-	SETOP(60, "CAY", 0x00, 0x00, 0x00, 0x00, 0x00, 0xB3);
-	SETOP(61, "CPX", 0xB4, 0xF4, 0x00, 0x00, 0xE4, 0x00);
-	SETOP(62, "CAX", 0x00, 0x00, 0x00, 0x00, 0x00, 0xB5);
-	SETOP(63, "ENT", 0xB8, 0x00, 0x00, 0x00, 0x00, 0x00);
-	SETOP(64, "RTI", 0x00, 0x00, 0x00, 0x00, 0x00, 0xC0);
-	SETOP(65, "INC", 0x00, 0xE3, 0x00, 0x00, 0xE1, 0xC1);
-	SETOP(66, "INY", 0x00, 0x00, 0x00, 0x00, 0x00, 0xC2);
-	SETOP(67, "IAY", 0x00, 0x00, 0x00, 0x00, 0x00, 0xC3);
-	SETOP(68, "INX", 0x00, 0x00, 0x00, 0x00, 0x00, 0xC4);
-	SETOP(69, "IAX", 0x00, 0x00, 0x00, 0x00, 0x00, 0xC5);
-	SETOP(70, "DEC", 0x00, 0x00, 0x00, 0x00, 0x00, 0xD1);
-	SETOP(71, "DEY", 0x00, 0x00, 0x00, 0x00, 0x00, 0xD2);
-	SETOP(72, "DAY", 0x00, 0xF3, 0x00, 0x00, 0xF1, 0xD3);
-	SETOP(73, "DEX", 0x00, 0x00, 0x00, 0x00, 0x00, 0xD4);
-	SETOP(74, "DAX", 0x00, 0x00, 0x00, 0x00, 0x00, 0xD5);
-	SETOP(75, "JSL", 0x00, 0x00, 0x00, 0x00, 0xE0, 0x00);
-	SETOP(76, "NOP", 0x00, 0x00, 0x00, 0x00, 0x00, 0xE8);
-	SETOP(77, "RTL", 0x00, 0x00, 0x00, 0x00, 0x00, 0xF0);
-	SETOP(78, "BRK", 0x00, 0x00, 0x00, 0x00, 0x00, 0xF8);
+	SETOP(5, "TAY", 0x00, 0x00, 0x00, 0x00, 0x00, 0x0B);
+	SETOP(6, "PHX", 0x0C, 0x00, 0x00, 0x00, 0x00, 0x00);
+	SETOP(7, "TAX", 0x00, 0x00, 0x00, 0x00, 0x00, 0x0D);
+	SETOP(8, "TYX", 0x00, 0x00, 0x00, 0x00, 0x00, 0x0E);
+	SETOP(9, "JMP", 0x00, 0xD0, 0x00, 0x00, 0x10, 0x00);
+	SETOP(10, "SBC", 0x11, 0x15, 0x00, 0x00, 0x13, 0x00);
+	SETOP(11, "PLP", 0x18, 0x00, 0x00, 0x00, 0x00, 0x00);
+	SETOP(12, "PLA", 0x19, 0x00, 0x00, 0x00, 0x00, 0x00);
+	SETOP(13, "PLY", 0x1A, 0x00, 0x00, 0x00, 0x00, 0x00);
+	SETOP(14, "TYA", 0x00, 0x00, 0x00, 0x00, 0x00, 0x1B);
+	SETOP(15, "PLX", 0x1C, 0x00, 0x00, 0x00, 0x00, 0x00);
+	SETOP(16, "TXA", 0x00, 0x00, 0x00, 0x00, 0x00, 0x1D);
+	SETOP(17, "TXY", 0x00, 0x00, 0x00, 0x00, 0x00, 0x1E);
+	SETOP(18, "JSR", 0x00, 0x20, 0x00, 0x00, 0x00, 0x00);
+	SETOP(19, "AND", 0x21, 0x2B, 0x00, 0x00, 0x29, 0x00);
+	SETOP(20, "ANY", 0x22, 0x82, 0x00, 0x00, 0x52, 0x00);
+	SETOP(21, "AAY", 0x00, 0x00, 0x00, 0x00, 0x00, 0x23);
+	SETOP(22, "ANX", 0x24, 0x84, 0x00, 0x00, 0x54, 0x00);
+	SETOP(23, "AAX", 0x00, 0x00, 0x00, 0x00, 0x00, 0x25);
+	SETOP(24, "STT", 0x28, 0x00, 0x00, 0x00, 0x00, 0x00);
+	SETOP(25, "BPO", 0x00, 0x00, 0x00, 0x00, 0x30, 0x00);
+	SETOP(26, "ORA", 0x31, 0x3B, 0x00, 0x00, 0x39, 0x00);
+	SETOP(27, "ORY", 0x32, 0x00, 0x00, 0x00, 0x62, 0x00);
+	SETOP(28, "OAY", 0x00, 0x00, 0x00, 0x00, 0x00, 0x33);
+	SETOP(29, "ORX", 0x34, 0x94, 0x00, 0x00, 0x64, 0x00);
+	SETOP(30, "OAX", 0x00, 0x00, 0x00, 0x00, 0x00, 0x35);
+	SETOP(31, "SEI", 0x00, 0x00, 0x00, 0x00, 0x00, 0x38);
+	SETOP(32, "BNG", 0x00, 0x00, 0x00, 0x00, 0x40, 0x00);
+	SETOP(33, "XOR", 0x41, 0x4B, 0x00, 0x00, 0x49, 0x00);
+	SETOP(34, "XRY", 0x42, 0xA2, 0x00, 0x00, 0x72, 0x00);
+	SETOP(35, "XAY", 0x00, 0x00, 0x00, 0x00, 0x00, 0x43);
+	SETOP(36, "XRX", 0x44, 0xA4, 0x00, 0x00, 0x74, 0x00);
+	SETOP(37, "XAX", 0x00, 0x00, 0x00, 0x00, 0x00, 0x45);
+	SETOP(38, "CLI", 0x00, 0x00, 0x00, 0x00, 0x00, 0x48);
+	SETOP(39, "BCS", 0x00, 0x00, 0x00, 0x00, 0x50, 0x00);
+	SETOP(40, "LSL", 0x51, 0x55, 0x00, 0x00, 0x53, 0x00);
+	SETOP(41, "SEC", 0x00, 0x00, 0x00, 0x00, 0x00, 0x58);
+	SETOP(42, "STA", 0x00, 0x7B, 0x8B, 0x9B, 0x5B, 0x00);
+	SETOP(43, "STY", 0x00, 0x7D, 0x8D, 0x00, 0x5D, 0x00);
+	SETOP(44, "STX", 0x00, 0x7E, 0x00, 0x9E, 0x5E, 0x00);
+	SETOP(45, "BCC", 0x00, 0x00, 0x00, 0x00, 0x60, 0x00);
+	SETOP(46, "LSR", 0x61, 0x65, 0x00, 0x00, 0x63, 0x00);
+	SETOP(47, "CLC", 0x00, 0x00, 0x00, 0x00, 0x00, 0x68);
+	SETOP(48, "LDA", 0x69, 0x79, 0x89, 0x99, 0x59, 0x00);
+	SETOP(49, "LDY", 0x6A, 0x7A, 0x8A, 0x00, 0x5A, 0x00);
+	SETOP(50, "LDX", 0x6C, 0x7C, 0x00, 0x9C, 0x5C, 0x00);
+	SETOP(51, "BEQ", 0x00, 0x00, 0x00, 0x00, 0x70, 0x00);
+	SETOP(52, "ROL", 0x71, 0x75, 0x00, 0x00, 0x73, 0x00);
+	SETOP(53, "SSP", 0x00, 0x00, 0x00, 0x00, 0x00, 0x78);
+	SETOP(54, "BNE", 0x00, 0x00, 0x00, 0x00, 0x80, 0x00);
+	SETOP(55, "ROR", 0x81, 0x85, 0x00, 0x00, 0x83, 0x00);
+	SETOP(56, "CSP", 0x00, 0x00, 0x00, 0x00, 0x00, 0x88);
+	SETOP(57, "BVS", 0x00, 0x00, 0x00, 0x00, 0x90, 0x00);
+	SETOP(58, "MUL", 0x91, 0x95, 0x00, 0x00, 0x93, 0x00);
+	SETOP(59, "SEV", 0x00, 0x00, 0x00, 0x00, 0x00, 0x98);
+	SETOP(60, "BVC", 0x00, 0x00, 0x00, 0x00, 0xA0, 0x00);
+	SETOP(61, "DIV", 0xA1, 0xA5, 0x00, 0x00, 0xA3, 0x00);
+	SETOP(62, "CLV", 0x00, 0x00, 0x00, 0x00, 0x00, 0xA8);
+	SETOP(63, "RTS", 0x00, 0x00, 0x00, 0x00, 0x00, 0xB0);
+	SETOP(64, "CMP", 0xB1, 0xF5, 0x00, 0x00, 0xE5, 0x00);
+	SETOP(65, "CPY", 0xB2, 0xF2, 0x00, 0x00, 0xE2, 0x00);
+	SETOP(66, "CAY", 0x00, 0x00, 0x00, 0x00, 0x00, 0xB3);
+	SETOP(67, "CPX", 0xB4, 0xF4, 0x00, 0x00, 0xE4, 0x00);
+	SETOP(68, "CAX", 0x00, 0x00, 0x00, 0x00, 0x00, 0xB5);
+	SETOP(69, "ENT", 0xB8, 0x00, 0x00, 0x00, 0x00, 0x00);
+	SETOP(70, "RTI", 0x00, 0x00, 0x00, 0x00, 0x00, 0xC0);
+	SETOP(71, "INC", 0x00, 0xE3, 0x00, 0x00, 0xE1, 0xC1);
+	SETOP(72, "INY", 0x00, 0x00, 0x00, 0x00, 0x00, 0xC2);
+	SETOP(73, "IAY", 0x00, 0x00, 0x00, 0x00, 0x00, 0xC3);
+	SETOP(74, "INX", 0x00, 0x00, 0x00, 0x00, 0x00, 0xC4);
+	SETOP(75, "IAX", 0x00, 0x00, 0x00, 0x00, 0x00, 0xC5);
+	SETOP(76, "DEC", 0x00, 0x00, 0x00, 0x00, 0x00, 0xD1);
+	SETOP(77, "DEY", 0x00, 0x00, 0x00, 0x00, 0x00, 0xD2);
+	SETOP(78, "DAY", 0x00, 0xF3, 0x00, 0x00, 0xF1, 0xD3);
+	SETOP(79, "DEX", 0x00, 0x00, 0x00, 0x00, 0x00, 0xD4);
+	SETOP(80, "DAX", 0x00, 0x00, 0x00, 0x00, 0x00, 0xD5);
+	SETOP(81, "JSL", 0x00, 0x00, 0x00, 0x00, 0xE0, 0x00);
+	SETOP(82, "NOP", 0x00, 0x00, 0x00, 0x00, 0x00, 0xE8);
+	SETOP(83, "RTL", 0x00, 0x00, 0x00, 0x00, 0x00, 0xF0);
+	SETOP(84, "BRK", 0x00, 0x00, 0x00, 0x00, 0x00, 0xF8);
 	uint8_t done = 0;
 	uint64_t address = 0x0000;
 	while (!(done & 1)) {
@@ -228,7 +235,7 @@ int asmmon() {
 				}
 				if (ins != NULL && !(done & 6)) {
 					uint8_t i;
-					for (i = 0; i < 77; i++) {
+					for (i = 0; i < OPNUM; i++) {
 						if (strcasecmp(opcodes[i].mnemonic, ins) == 0) {
 							if (addrmode == 0 && (opcodes[i].impl || opcodes[i].impl == CPS)) {
 								done |= 8;
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 #",
diff --git a/sux.c b/sux.c
index 4df60cb..08f5ebe 100644
--- a/sux.c
+++ b/sux.c
@@ -17,7 +17,6 @@ uint8_t threads_done = 0;
 uint8_t lines[THREADS];
 pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
 pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
-pthread_barrier_t bar;
 struct suxthr {
 	struct sux sx;
 	uint8_t th;
@@ -175,6 +174,39 @@ void *run(void *args) {
 					addr[0xFF91] = cpu->sp >> 8;
 				}
 				break;
+			case TAY: /* Transfer Accumulator to Y. */
+			case TAX: /* Transfer Accumulator to Y. */
+			case TYX: /* Transfer Y to X. */
+			case TYA: /* Transfer Y to Accumulator. */
+			case TXA: /* Transfer X to Accumulator. */
+			case TXY: /* Transfer X to Y. */
+				if (opcode == TAY)
+					cpu->y[thread] = cpu->a[thread];
+				if (opcode == TAX)
+					cpu->x[thread] = cpu->a[thread];
+				if (opcode == TYX)
+					cpu->x[thread] = cpu->y[thread];
+				if (opcode == TYA)
+					cpu->a[thread] = cpu->y[thread];
+				if (opcode == TXA)
+					cpu->a[thread] = cpu->x[thread];
+				if (opcode == TXY)
+					cpu->y[thread] = cpu->x[thread];
+				if (opcode == TYA || opcode == TXA) {
+					cpu->z[thread] = (cpu->a[thread] == 0);
+					cpu->n[thread] = (cpu->a[thread] >> 63);
+				}
+				if (opcode == TAY || opcode == TXY) {
+					cpu->z[thread] = (cpu->y[thread] == 0);
+					cpu->n[thread] = (cpu->y[thread] >> 63);
+				}
+				if (opcode == TAX || opcode == TYX) {
+					cpu->z[thread] = (cpu->x[thread] == 0);
+					cpu->n[thread] = (cpu->x[thread] >> 63);
+				}
+				(cpu->z[thread]) ? (cpu->ps |= (Z << 8*thread)) : (cpu->ps &= ~(Z << 8*thread));
+				(cpu->n[thread]) ? (cpu->ps |= (N << 8*thread)) : (cpu->ps &= ~(N << 8*thread));
+				break;
 			case PHX: /* PusH X register to stack. */
 				tmp = addr[cpu->pc[thread]++];
 				if (tmp > 7)
@@ -1413,7 +1445,6 @@ int main(int argc, char **argv) {
 		inst[i] = 0;
 	}
 	pthread_t therads[THREADS];
-	pthread_barrier_init(&bar, NULL, THREADS);
 	int result;
 	puts("\033[2J\033[H");
 	for (int i = 0; i < THREADS; i++) {
@@ -1425,7 +1456,6 @@ int main(int argc, char **argv) {
 		pthread_cond_wait(&cond, &mutex);
 	}
 	pthread_mutex_unlock(&mutex);
-	pthread_barrier_destroy(&bar);
 #if bench
 	if (threads_done == THREADS) {
 		double tm_sec, tm_usec, tm[THREADS], ttm;
diff --git a/test/reg-transfer.s b/test/reg-transfer.s
new file mode 100644
index 0000000..580020c
--- /dev/null
+++ b/test/reg-transfer.s
@@ -0,0 +1,23 @@
+; Test register transfer instructions.
+;
+; by mr b0nk 500 <b0nk @b0nk.xyz>
+
+cps
+inc		; Increment the accumulator.
+tay		; Transfer the accumulator to the y register.
+tax		; Do the same thing, but with the x register.
+jmp $1		; Loop forever.
+
+.org $8000
+cps
+inc		; Increment the accumulator.
+tay		; Transfer the accumulator to the y register.
+tax		; Do the same thing, but with the x register.
+jmp $1		; Loop forever.
+
+.org $FF50
+.qword $8000
+
+; Execute the program.
+done
+