diff --git a/cpu.c b/cpu.c
index 65e60d4..8c88959 100644
--- a/cpu.c
+++ b/cpu.c
@@ -244,7 +244,7 @@ bit(uint8_t arg)
 {
 	regs.status.zero = (regs.a & arg) == 0;
 	regs.status.overflow = (arg & (1 << 6)) > 0;
-	regs.status.negative = (arg & (1 << 7)) > 0;
+	STATUS_UPDATE_NEGATIVE(arg);
 }
 
 static void
@@ -329,7 +329,7 @@ cmp(uint8_t arg)
 
 	regs.status.carry = regs.a >= arg;
 	regs.status.zero = regs.a == arg;
-	regs.status.negative = (tmp & (1 << 7)) > 0;
+	STATUS_UPDATE_NEGATIVE(tmp);
 }
 
 static void
@@ -341,7 +341,7 @@ cpx(uint8_t arg)
 
 	regs.status.carry = regs.x >= arg;
 	regs.status.zero = regs.x == arg;
-	regs.status.negative = (tmp & (1 << 7)) > 0;
+	STATUS_UPDATE_NEGATIVE(tmp);
 }
 
 static void
@@ -353,37 +353,52 @@ cpy(uint8_t arg)
 
 	regs.status.carry = regs.y >= arg;
 	regs.status.zero = regs.y == arg;
-	regs.status.negative = (tmp & (1 << 7)) > 0;
+	STATUS_UPDATE_NEGATIVE(tmp);
 }
 
 static void
 dec(uint16_t mem)
 {
 	memwrite(mem, peek(mem) - 1);
+
+	STATUS_UPDATE_ZERO(peek(mem));
+	STATUS_UPDATE_NEGATIVE(peek(mem));
 }
 
 static void
-dex(uint8_t arg)
+dex(void)
 {
-/* TODO: complete this */
+	regs.x--;
+
+	STATUS_UPDATE_ZERO(regs.x);
+	STATUS_UPDATE_NEGATIVE(regs.x);
 }
 
 static void
-dey(uint8_t arg)
+dey(void)
 {
-/* TODO: complete this */
+	regs.y--;
+
+	STATUS_UPDATE_ZERO(regs.y);
+	STATUS_UPDATE_NEGATIVE(regs.y);
 }
 
 static void
 eor(uint8_t arg)
 {
-/* TODO: complete this */
+	regs.a ^= arg;
+
+	STATUS_UPDATE_ZERO(regs.a);
+	STATUS_UPDATE_NEGATIVE(regs.a);
 }
 
 static void
-inc(uint8_t arg)
+inc(uint16_t mem)
 {
-/* TODO: complete this */
+	memwrite(mem, peek(mem) + 1);
+
+	STATUS_UPDATE_ZERO(peek(mem));
+	STATUS_UPDATE_NEGATIVE(peek(mem));
 }
 
 static void
@@ -398,13 +413,16 @@ inx(void)
 static void
 iny(uint8_t arg)
 {
-/* TODO: complete this */
+	regs.y++;
+
+	STATUS_UPDATE_ZERO(regs.y);
+	STATUS_UPDATE_NEGATIVE(regs.y);
 }
 
 static void
 jmp(uint8_t arg)
 {
-/* TODO: complete this */
+	regs.pc = arg;
 }
 
 static void
@@ -416,7 +434,6 @@ jsr(uint8_t arg)
 static void
 lda(uint8_t arg)
 {
-	printf("arg1 $%02X\n", arg);
 	regs.a = arg;
 
 	STATUS_UPDATE_ZERO(regs.a);
@@ -426,13 +443,19 @@ lda(uint8_t arg)
 static void
 ldx(uint8_t arg)
 {
-/* TODO: complete this */
+	regs.x = arg;
+
+	STATUS_UPDATE_ZERO(regs.x);
+	STATUS_UPDATE_NEGATIVE(regs.x);
 }
 
 static void
 ldy(uint8_t arg)
 {
-/* TODO: complete this */
+	regs.y = arg;
+
+	STATUS_UPDATE_ZERO(regs.y);
+	STATUS_UPDATE_NEGATIVE(regs.y);
 }
 
 static void
@@ -444,13 +467,16 @@ lsr(uint8_t arg)
 static void
 nop(uint8_t arg)
 {
-/* TODO: complete this */
+	return;
 }
 
 static void
 ora(uint8_t arg)
 {
-/* TODO: complete this */
+	regs.a |= arg;
+
+	STATUS_UPDATE_ZERO(regs.a);
+	STATUS_UPDATE_NEGATIVE(regs.a);
 }
 
 static void
@@ -975,11 +1001,11 @@ interpret(void)
 			cycles += 7;
 			break;
 		case 0xca:
-			dex(opcode_arg(AM_ACC));
+			dex();
 			cycles += 2;
 			break;
 		case 0x88:
-			dey(opcode_arg(AM_ACC));
+			dey();
 			cycles += 2;
 			break;
 		case 0x49: