Add TYA instruction

src/6502/6502.h

@@ -31,6 +31,7 @@ typedef unsigned short word; // 16 bit
 #define INS_TSX 0xBA // TSX Implied
 #define INS_TXA 0x8A // TXA Implied
 #define INS_TXS 0x9A // TXS Implied
+#define INS_TYA 0x98 // TYA Implied
 
 #define INS_JSR 0x20 // JSR
 #define INS_RTS 0x60 // RTS

src/6502/main.c

@@ -157,6 +157,14 @@ void execute() {
 			        cpu.SP = cpu.X;
 				cpu.PC++;
 			        break;
+         		case INS_TYA:
+			        cpu.A = cpu.Y;
+				cpu.Z = (cpu.A == 0);
+				cpu.N = (cpu.A & 0b1000000) > 0;
+				cpu.PC++;
+			        break;
+		        
+				
 	   		case INS_JSR:
 				word jsr_addr = fetch_word();
 				write_word(cpu.PC - 1, cpu.SP);

src/6502/test.bin

@@ -1 +1 @@
-<EFBFBD>B<EFBFBD>
+<EFBFBD>S<EFBFBD>