Implemented complex expressions

src/build/Function.go

@@ -122,60 +122,45 @@ func (f *Function) CompileInstruction(line token.List) error {
 
 // ExpressionToRegister moves the result of an expression into the given register.
 func (f *Function) ExpressionToRegister(root *expression.Expression, register cpu.Register) error {
+	operation := root.Token
+
 	if root.IsLeaf() {
-		return f.TokenToRegister(root.Token, register)
+		return f.TokenToRegister(operation, register)
 	}
 
 	left := root.Children[0]
 	right := root.Children[1]
 
-	f.ExpressionToRegister(left, register)
+	err := f.ExpressionToRegister(left, register)
 
-	if right.IsLeaf() {
-		value := right.Token.Text()
-		n, err := strconv.Atoi(value)
-
-		if err != nil {
-			return err
-		}
-
-		switch root.Token.Text() {
-		case "+":
-			f.Assembler.RegisterNumber(asm.ADD, register, n)
-
-		case "-":
-			f.Assembler.RegisterNumber(asm.SUB, register, n)
-
-		case "*":
-			f.Assembler.RegisterNumber(asm.MUL, register, n)
-
-		case "/":
-			f.Assembler.RegisterNumber(asm.DIV, register, n)
-		}
-
-		return nil
-	} else {
-		temporary, _ := f.CPU.FindFree(f.CPU.General)
-		f.CPU.Use(temporary)
-		f.ExpressionToRegister(right, temporary)
-		f.CPU.Free(temporary)
-
-		switch root.Token.Text() {
-		case "+":
-			f.Assembler.RegisterRegister(asm.ADD, register, temporary)
-
-		case "-":
-			f.Assembler.RegisterRegister(asm.SUB, register, temporary)
-
-		case "*":
-			f.Assembler.RegisterRegister(asm.MUL, register, temporary)
-
-		case "/":
-			f.Assembler.RegisterRegister(asm.DIV, register, temporary)
-		}
+	if err != nil {
+		return err
 	}
 
-	return errors.New(errors.NotImplemented, f.File, root.Token.Position)
+	return f.Execute(operation, register, right)
+}
+
+// Execute executes an operation on a register with a value operand.
+func (f *Function) Execute(operation token.Token, register cpu.Register, value *expression.Expression) error {
+	if value.IsLeaf() {
+		return f.Calculate(register, operation, value.Token)
+	}
+
+	temporary, found := f.CPU.FindFree(f.CPU.General)
+
+	if !found {
+		panic("no free registers")
+	}
+
+	f.CPU.Use(temporary)
+	defer f.CPU.Free(temporary)
+	err := f.ExpressionToRegister(value, temporary)
+
+	if err != nil {
+		return err
+	}
+
+	return f.CalculateRegisterRegister(operation, register, temporary)
 }
 
 // TokenToRegister moves a token into a register.
@@ -190,7 +175,7 @@ func (f *Function) TokenToRegister(t token.Token, register cpu.Register) error {
 			return errors.New(&errors.UnknownIdentifier{Name: name}, f.File, t.Position)
 		}
 
-		f.Assembler.MoveRegisterRegister(register, variable.Register)
+		f.Assembler.RegisterRegister(asm.MOVE, register, variable.Register)
 		return nil
 
 	case token.Number: