When generating code for a modern programming language, one quickly realizes that there are commands that are not provided by a specific machine. On the other hand, the instruction sets of modern computers change so rapidly that it doesn't make sense to tie the compiler too closely to randomly available operations. Such a restriction could mean that one would have to completely rewrite the compiler after just a few years. To avoid this, code is generated for an idealized machine, whose instructions only need to be implemented on the various specific target machines. On one hand, this approach facilitates the portability of the compiler. On the other hand, it also simplifies the translation itself, as the instruction set can be adjusted accordingly.