Implemented infinite loops

src/build/asm/Assembler.go

@@ -44,14 +44,32 @@ func (a *Assembler) Finalize() ([]byte, []byte) {
 
 		case CALL:
 			code = x64.Call(code, 0x00_00_00_00)
+			size := 4
 			label := x.Data.(*Label)
-			nextInstructionAddress := len(code)
+			nextInstructionAddress := Address(len(code))
 
 			pointers = append(pointers, Pointer{
-				Position: Address(len(code) - 4),
+				Position: Address(len(code) - size),
+				Size:     uint8(size),
 				Resolve: func() Address {
 					destination := labels[label.Name]
-					distance := int32(destination) - int32(nextInstructionAddress)
+					distance := destination - nextInstructionAddress
+					return Address(distance)
+				},
+			})
+
+		case JUMP:
+			code = x64.Jump8(code, 0x00)
+			size := 1
+			label := x.Data.(*Label)
+			nextInstructionAddress := Address(len(code))
+
+			pointers = append(pointers, Pointer{
+				Position: Address(len(code) - size),
+				Size:     uint8(size),
+				Resolve: func() Address {
+					destination := labels[label.Name]
+					distance := destination - nextInstructionAddress
 					return Address(distance)
 				},
 			})
@@ -67,8 +85,22 @@ func (a *Assembler) Finalize() ([]byte, []byte) {
 	// dataStart := config.BaseAddress + config.CodeOffset + Address(len(code))
 
 	for _, pointer := range pointers {
-		slice := code[pointer.Position : pointer.Position+4]
-		binary.LittleEndian.PutUint32(slice, pointer.Resolve())
+		slice := code[pointer.Position : pointer.Position+Address(pointer.Size)]
+		address := pointer.Resolve()
+
+		switch pointer.Size {
+		case 1:
+			slice[0] = uint8(address)
+
+		case 2:
+			binary.LittleEndian.PutUint16(slice, uint16(address))
+
+		case 4:
+			binary.LittleEndian.PutUint32(slice, uint32(address))
+
+		case 8:
+			binary.LittleEndian.PutUint64(slice, uint64(address))
+		}
 	}
 
 	return code, data

src/build/asm/Instructions.go

@@ -44,6 +44,16 @@ func (a *Assembler) Call(name string) {
 	})
 }
 
+// Jump jumps to a position that is identified by a label.
+func (a *Assembler) Jump(name string) {
+	a.Instructions = append(a.Instructions, Instruction{
+		Mnemonic: JUMP,
+		Data: &Label{
+			Name: name,
+		},
+	})
+}
+
 // Return returns back to the caller.
 func (a *Assembler) Return() {
 	a.Instructions = append(a.Instructions, Instruction{Mnemonic: RETURN})

src/build/asm/Mnemonic.go

@@ -9,6 +9,7 @@ const (
 	SYSCALL
 	LABEL
 	CALL
+	JUMP
 )
 
 // String returns a human readable version.
@@ -28,6 +29,9 @@ func (m Mnemonic) String() string {
 
 	case CALL:
 		return "call"
+
+	case JUMP:
+		return "jump"
 	}
 
 	return "NONE"

src/build/asm/Pointer.go

@@ -8,5 +8,6 @@ type Address = uint32
 // Resolve:  The function that will return the final address.
 type Pointer struct {
 	Position Address
+	Size     uint8
 	Resolve  func() Address
 }