implement JMZ

2 files changed, 55 insertions, 1 deletions

diff --git a/src/vm/instruction.js b/src/vm/instruction.js
index 878d20b..2afd3f7 100644
--- a/src/vm/instruction.js
+++ b/src/vm/instruction.js
@@ -107,3 +107,20 @@ exports.JMP = function(core, pc, ins) {
 	const dstLoc = core.getLocation(pc, ins.a);
 	return [dstLoc];
 }
+
+
+exports.JMZ = function(core, pc, ins) {
+	let test
+	if (ins.b.mode === AddrMode.Immediate) {
+		test = (ins.b.value === 0);
+	} else {
+		const src = core.getValue(pc, ins.b);
+		test = (src.b.value === 0);
+	}
+
+	if (test) {
+		return [core.getLocation(pc, ins.a)];
+	} else {
+		return [core.normalize(pc, 1)];
+	}
+}
diff --git a/src/vm/instruction.test.js b/src/vm/instruction.test.js
index 8efa47f..6175ab2 100644
--- a/src/vm/instruction.test.js
+++ b/src/vm/instruction.test.js
@@ -4,7 +4,7 @@ const { Core } = require('./core.js');
 const { 
 	DAT, 
 	MOV, ADD, SUB, CMP, SLT,
-	JMP,
+	JMP, JMZ, JMN, DJN, SPL,
 } = require('./instruction.js');
 
 
@@ -391,3 +391,40 @@ test('JMP correctly jumps', () => {
 
 	expect(JMP(core, pc, ins)).toEqual([CORESIZE-1]);
 });
+
+
+test('JMZ correctly jumps in non-immediate mode', () => {
+	const core = new Core(CORESIZE);
+	const pc = 2;
+	core.data[pc] = {
+		opcode: 'JMZ',
+		a: { mode: 'direct', value: -3 },
+		b: { mode: 'direct', value: 1 },
+	};
+	core.data[pc+1] = {
+		opcode: 'JMZ',
+		a: { mode: 'direct', value: -3 },
+		b: { mode: 'direct', value: 1 },
+	};
+	const ins = core.data[pc];
+
+	expect(JMZ(core, pc, ins)).toEqual([pc+1]);
+	core.data[pc+1].b.value = 0;
+	expect(JMZ(core, pc, ins)).toEqual([CORESIZE-1]);
+});
+
+
+test('JMZ correctly jumps in immediate mode', () => {
+	const core = new Core(CORESIZE);
+	const pc = 2;
+	core.data[pc] = {
+		opcode: 'JMZ',
+		a: { mode: 'direct', value: -3 },
+		b: { mode: 'immediate', value: 1 },
+	};
+	const ins = core.data[pc];
+
+	expect(JMZ(core, pc, ins)).toEqual([pc+1]);
+	core.data[pc].b.value = 0;
+	expect(JMZ(core, pc, ins)).toEqual([CORESIZE-1]);
+});