1 files changed, 31 insertions, 0 deletions
diff --git a/sux.c b/sux.c
new file mode 100644
index 0000000..4e64277
--- /dev/null
+++ b/sux.c
@@ -0,0 +1,31 @@
+#include <limits.h>
+#include "opcode.h"
+#include <stdint.h>
+uint64_t a; /* Accumulator. */
+uint64_t y; /* Y index. */
+uint64_t x; /* X index. */
+uint64_t ps; /* Processor status. */
+
+uint64_t alu(uint8_t opcode, uint64_t value) {
+	uint64_t sum;
+	uint8_t carry, vf;
+	switch(opcode) {
+		/* Add with carry. */
+		case ADC:
+			sum = a+value+carry;
+			vf = (~(a^value) & (a^sum & 0x80));
+			carry = (sum < value) ? 1 : 0;
+			a |= sum;
+			break;
+		/* Subtract with carry. */
+		case SBC:
+			sum = a-value-!carry
+			vf = (a^value) & (a^sum) & 0x80;
+			carry = (sum > value) ? 1 : 0;
+			a |= sum;
+			break;
+
+
+
+	}
+}