diff --git a/src/build/register/RegisterNumber.go b/src/build/register/RegisterNumber.go
index 298c4d7..a6b5aa6 100644
--- a/src/build/register/RegisterNumber.go
+++ b/src/build/register/RegisterNumber.go
@@ -11,20 +11,27 @@ func (f *Machine) RegisterNumber(mnemonic asm.Mnemonic, a cpu.Register, b int) {
 		f.SaveRegister(a)
 	}
 
-	if sizeof.Signed(int64(b)) == 8 {
-		tmp := f.NewRegister()
-		f.Assembler.RegisterNumber(asm.MOVE, tmp, b)
-		f.UseRegister(tmp)
-		f.postInstruction()
-		f.Assembler.RegisterRegister(mnemonic, a, tmp)
-		f.postInstruction()
-		f.FreeRegister(tmp)
-	} else {
+	// The `MOVE` operation is very flexible and works with any type of immediate number.
+	if mnemonic == asm.MOVE {
 		f.Assembler.RegisterNumber(mnemonic, a, b)
+		f.UseRegister(a)
 		f.postInstruction()
+		return
 	}
 
-	if mnemonic == asm.MOVE {
-		f.UseRegister(a)
+	// If the number only needs 32 bits, we can encode the instruction.
+	if sizeof.Signed(int64(b)) <= 4 {
+		f.Assembler.RegisterNumber(mnemonic, a, b)
+		f.postInstruction()
+		return
 	}
+
+	// If the number needs 64 bits, we need to use a temporary register.
+	tmp := f.NewRegister()
+	f.Assembler.RegisterNumber(asm.MOVE, tmp, b)
+	f.UseRegister(tmp)
+	f.postInstruction()
+	f.Assembler.RegisterRegister(mnemonic, a, tmp)
+	f.postInstruction()
+	f.FreeRegister(tmp)
 }