Improved code generation

src/build/core/CompileCall.go

@@ -35,6 +35,12 @@ func (f *Function) CompileCall(root *expression.Expression) error {
 		return err
 	}
 
+	f.SaveRegister(f.cpu.Output[0])
+
+	for _, register := range registers {
+		f.SaveRegister(register)
+	}
+
 	// Push
 	for _, register := range f.cpu.General {
 		if f.cpu.IsUsed(register) {