1. A method of executing program code during conversion of subject code executable by a subject processor into target code executable by a target processor, in combination with native code that is natively executable by the target processor, said method comprising the steps of: executing a first subject code portion on the target processor as translated target code; calling from the first subject code portion to execute a native code portion natively on the target processor; calling from the native code portion to execute a second subject code portion as translated target code; returning from execution of the second subject code portion to execution of the native code portion; and returning from execution of the native code portion to execution of the first subject code portion.