[fpc-pascal] Does the compiler make prodigious use of use ENTER instruction?

[Marco van de Voort]

Op 12-12-2023 om 17:48 schreef Anthony Walter via fpc-pascal:
> Iwas reading this article today on the Microsoft website about the 
> mysterious x86 ENTER instruction. The article states that it's primary 
> purpose is to support Pascal and similar compilers to allow for 
> preserving local variables on the stack when using with nested functions.
>
> Here is the article:
>
> https://devblogs.microsoft.com/oldnewthing/20231211-00/?p=109126
>
> Do any of the compiler devs know if Pascal programs for the x86 
> instruction set are using ENTER and its second argument to the best 
> possible effect? I am curious.
>
No, and if they do, they don't do in the way they are meant to. These 
are very old instructions and the intended use has a nesting limit (of 
32 levels iiirc).  Because of that limit, modern compilers don't use them.

Some forms of enter and leave are use as peephole optimizations.