conditional registers per function, possible or not?

[Andi Kleen]

Dylan_S_Cuthbert@hq.scei.sony.co.jp writes:

> I didn't get a response to my last question along these lines:
> 
> Is it at all possible within the current gcc frame work to be able to use
> conditional registers selected on a per function basis?
> 
> Something like this perhaps:
> 
> int SpecialFunction( ) __attribute__ ((registers_begin( $8))) __attribute__
> ((registers_end( $20)));
> 
> Ideas?

Linux kernel does this sometimes. It just uses an asm with the appropiate
clobbers and codes the function call in inline assembler.

Disadvantage: not schedulable

-Andi