Implemented if statements

src/build/asm/Assembler.go

@@ -66,8 +66,32 @@ func (a Assembler) Finalize() ([]byte, []byte) {
 		case COMMENT:
 			continue
 
-		case JUMP:
-			code = x64.Jump8(code, 0x00)
+		case COMPARE:
+			switch operands := x.Data.(type) {
+			case *RegisterNumber:
+				code = x64.CompareRegisterNumber(code, operands.Register, operands.Number)
+			case *RegisterRegister:
+				code = x64.CompareRegisterRegister(code, operands.Destination, operands.Source)
+			}
+
+		case JUMP, JE, JNE, JG, JL, JGE, JLE:
+			switch x.Mnemonic {
+			case JUMP:
+				code = x64.Jump8(code, 0x00)
+			case JE:
+				code = x64.Jump8IfEqual(code, 0x00)
+			case JNE:
+				code = x64.Jump8IfNotEqual(code, 0x00)
+			case JG:
+				code = x64.Jump8IfGreater(code, 0x00)
+			case JL:
+				code = x64.Jump8IfLess(code, 0x00)
+			case JGE:
+				code = x64.Jump8IfGreaterOrEqual(code, 0x00)
+			case JLE:
+				code = x64.Jump8IfLessOrEqual(code, 0x00)
+			}
+
 			size := 1
 			label := x.Data.(*Label)
 			nextInstructionAddress := Address(len(code))

src/build/asm/Instructions.go

@@ -34,10 +34,10 @@ func (a *Assembler) Register(mnemonic Mnemonic, register cpu.Register) {
 	})
 }
 
-// Label adds a label at the current position.
-func (a *Assembler) Label(name string) {
+// Label adds an instruction using a label.
+func (a *Assembler) Label(mnemonic Mnemonic, name string) {
 	a.Instructions = append(a.Instructions, Instruction{
-		Mnemonic: LABEL,
+		Mnemonic: mnemonic,
 		Data: &Label{
 			Name: name,
 		},

src/build/asm/Mnemonic.go

@@ -7,7 +7,14 @@ const (
 	ADD
 	CALL
 	COMMENT
+	COMPARE
 	DIV
+	JE
+	JNE
+	JG
+	JGE
+	JL
+	JLE
 	JUMP
 	MUL
 	LABEL
@@ -28,10 +35,24 @@ func (m Mnemonic) String() string {
 		return "call"
 	case COMMENT:
 		return "comment"
+	case COMPARE:
+		return "compare"
 	case DIV:
 		return "div"
 	case JUMP:
 		return "jump"
+	case JE:
+		return "jump =="
+	case JNE:
+		return "jump !="
+	case JL:
+		return "jump <"
+	case JG:
+		return "jump >"
+	case JLE:
+		return "jump <="
+	case JGE:
+		return "jump >="
 	case LABEL:
 		return "label"
 	case MOVE: