implement CMP

1 files changed, 29 insertions, 0 deletions

diff --git a/src/vm/instruction.js b/src/vm/instruction.js
index 146a88b..df5369d 100644
--- a/src/vm/instruction.js
+++ b/src/vm/instruction.js
@@ -52,3 +52,32 @@ exports.SUB = function(core, pc, ins) {
 
 	return [pc + 1];
 }
+
+
+exports.CMP = function(core, pc, ins) {
+	if (ins.a.mode === AddrMode.Immediate) {
+		const test = core.getValue(pc, ins.b);
+		if (test.b.value === ins.a.value) {
+			return [pc + 2];
+		} else {
+			return [pc + 1];
+		}
+	} else {
+		const left = core.getValue(pc, ins.a);
+		const right = core.getValue(pc, ins.b);
+		if (
+			// compare opcode
+			left.opcode  === right.opcode  &&
+			// compare a-field
+			left.a.mode  === right.a.mode  &&
+			left.a.value === right.a.value &&
+			// compare b-field
+			left.b.mode  === right.b.mode  &&
+			left.b.value === right.b.value
+		) {
+			return [pc + 2];
+		} else {
+			return [pc + 1];
+		}
+	}
+}