Add loading programs from roms

src/6502/6502.h

@@ -7,15 +7,24 @@ typedef unsigned short word; // 16 bit
 
 #define INS_LDA_IM 0xA9 // LDA Immediate
 #define INS_LDA_ZP 0xA5 // LDA Zero Page
-#define INS_LDA_ZPX 0xB5 // LDA Zero Page.X
+#define INS_LDA_ZPX 0xB5 // LDA Zero Page,X
+#define INS_LDA_ABS 0xAD // LDA Absolute
+#define INS_LDA_ABSX 0xBD // LDA Absolute,X
+#define INS_LDA_ABSY 0xB9 // LDA Absolute,Y
+#define INS_LDA_INX 0xA1 // LDA Indirect,X
+#define INS_LDA_INY 0xB1 // LDA Indirect,Y
 
 #define INS_LDX_IM 0xA2 // LDX Immediate
 #define INS_LDX_ZP 0xA6 // LDX Zero Page
-#define INS_LDX_ZPY 0xB6 // LDX Zero Page.Y
+#define INS_LDX_ZPY 0xB6 // LDX Zero Page,Y
+#define INS_LDX_ABS 0xAE // LDX Absolute
+#define INS_LDX_ABSY 0xBE // LDX Absolute,Y
 
 #define INS_LDY_IM 0xA0 // LDY Immediate
 #define INS_LDY_ZP 0xA4 // LDY Zero Page
-#define INS_LDY_ZPX 0xB4 // LDY Zero Page.X
+#define INS_LDY_ZPX 0xB4 // LDY Zero Page,X
+#define INS_LDY_ABS 0xAC // LDY Absolute
+#define INS_LDY_ABSX 0xBC // LDY Absolute,X
 
 #define INS_JSR 0x20 // JSR
 #define INS_RTS 0x60 // RTS

src/6502/main.c

@@ -6,13 +6,13 @@ struct CPU cpu;
 struct MEMORY mem;
 byte cycles;
 
-void memory_init (){ // FIXME: Warning: mem not used
+void memory_init () {
 	for (int i = 0; i < MAX_MEMORY; i++){
 		mem.memory[i] = 0;
 	}
 }
 void reset () {
-	cpu.PC = 0xFFFC; 
+        cpu.PC = 0x0000; // FIXME //0xFFFC; 
 	cpu.SP = 0x0000; //FIXME
 	cpu.A = cpu.X = cpu.Y = 0;
 	cpu.C = cpu.Z = cpu.I = cpu.D = cpu.B = cpu.V = cpu.N = 0;
@@ -47,15 +47,18 @@ word fetch_word() {
 	return data;
 }
 
-byte read_byte(byte addr) {
+byte read_byte(word addr) {
 	byte data = mem.memory[addr];
 	cycles--;
+	cpu.PC++;
 	return data;
 }
 
-word read_word(byte addr) {
+word read_word(word addr) {
 	word data = mem.memory[addr];
 	data |= (mem.memory[addr+1] << 8);
+	cpu.PC++;
+	cpu.PC++;
 	cycles -= 2;
 	return data;
 }
@@ -118,7 +121,6 @@ void execute(byte exec_cycles) {
 				cpu.X = read_byte(zero_page_y_addr);	
 				cpu.Z = (cpu.X == 0);
 				cpu.N = (cpu.X & 0b1000000) > 0;
-				printf("test\n");
 				break;
 
 			case INS_LDY_IM:
@@ -152,33 +154,26 @@ void execute(byte exec_cycles) {
 				// TODO
 				break;
 			default: 
-				printf("Unhandled instruction: %04X\n", instruction);
-				cycles--;
+				printf("%04X: Unhandled instruction: %04X\n", cpu.PC, instruction);
+				cycles = 0;
 		}
 	}
 }
-int main() {
+int main(int argc, char *argv[]) {
 	reset();
-
-	mem.memory[0xFFFC] = INS_JSR;
-	mem.memory[0xFFFD] = 0x42;
-	mem.memory[0xFFFE] = 0x42;
-
-	mem.memory[0x4242] = INS_LDX_IM;
-	mem.memory[0x4243] = 0x66;
-
-	mem.memory[0x4244] = INS_LDY_IM;
-	mem.memory[0x4245] = 0x11;
-
-	mem.memory[0x4246] = INS_LDX_ZP;
-	mem.memory[0x4247] = 0x68;
-	mem.memory[0x68] = 0x75;
-
-	mem.memory[0x4248] = INS_LDY_ZP;
-	mem.memory[0x4249] = 0x69;
-	mem.memory[0x69] = 0x88;
-
-	execute(18);
+	// TODO make loading from rom
+	FILE *infile = fopen(argv[1], "rb");
+	char ch;
+	int pos = 0;
+	while (1) { // FIXME
+	  ch = fgetc(infile);
+	  if (ch == EOF)
+	    break;
+	  mem.memory[pos] = ch;
+	  pos++;
+	}
+        
+	execute(5); // FIXME: count how many circles is needed based on instructions
 	dump_cpu(cpu);
 	return 0;
 }

src/6502/test.bin

@@ -0,0 +1 @@
+ｩVV