fix peek

1 files changed, 11 insertions, 7 deletions

diff --git a/cpu.c b/cpu.c
index a8c6ceb..f018a44 100644
--- a/cpu.c
+++ b/cpu.c
@@ -47,12 +47,12 @@ uint8_t memory[0x16000];
 uint8_t program[] = { 0xa9, 0xc0, 0xaa, 0xe8, 0x00 };
 
 uint8_t
-peek(uint16_t addr)
+peek(uint8_t addr)
 {
 	return memory[addr];
 }
 
-uint16_t
+uint8_t
 peek16(uint16_t addr)
 {
 	/* bytes are stored in little-endian (low then high) */
@@ -93,7 +93,10 @@ lda(enum addressing_mode mode)
 {
 	uint8_t arg, val;
 
-	arg = peek(regs.pc++);
+	if (mode != AM_ABS && mode != AM_ABS_X && mode != AM_ABS_Y)
+		arg = peek(regs.pc++);
+	else
+		arg = peek16(regs.pc++);
 
 	switch (mode) {
 	case AM_IMM:	/* $A9 */
@@ -103,16 +106,16 @@ lda(enum addressing_mode mode)
 		val = peek(arg % 256);
 		break;
 	case AM_ABS:	/* $AD */
-		val = peek(arg);
+		val = peek16(arg);
 		break;
 	case AM_ZP_X:	/* $B5 */
 		val = peek((arg + regs.x) % 256);
 		break;
 	case AM_ABS_X:	/* $BD */
-		val = peek(arg + regs.x);
+		val = peek16(arg + regs.x);
 		break;
 	case AM_ABS_Y:	/* $B9 */
-		val = peek(arg + regs.y);
+		val = peek16(arg + regs.y);
 		break;
 	case AM_IND_X:	/* $A1 */
 		val = peek(peek((arg + regs.x) % 256) + peek((arg + regs.x + 1) % 256) * 256);
@@ -121,7 +124,8 @@ lda(enum addressing_mode mode)
 		val = peek(peek(arg) + peek((arg + 1) % 256) * 256 + regs.y);
 		break;
 	default:
-		regs.pc--;
+		fprintf(stderr, "INVALID LDA ADDRESSING MODE\n");
+		abort();
 		return;
 	}