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Re: Doc for -fcall-used-REG and -fcall-saved-REG
- To: Gavin Romig-Koch <gavin at cygnus dot com>
- Subject: Re: Doc for -fcall-used-REG and -fcall-saved-REG
- From: Jeffrey A Law <law at cygnus dot com>
- Date: Wed, 14 Oct 1998 10:22:24 -0600
- cc: egcs at cygnus dot com
- Reply-To: law at cygnus dot com
In message <m0zTED4-000s8JC@cetus.cygnus.com>you write:
> My question is whether we need to keep the above comment for
> other fixed pervasive role registers (other than the sp and fp);
> something like:
>
> Use of this flag for the stack pointer or the frame pointer is
> an error. Use of this flag for a register that has a fixed
> pervasive role in the machine's execution model, other than
> the stack pointer and frame pointer, will produce disastrous
> results.
>
> Or wether we know that there are no other such fixed registers,
> and can drop that second sentance? Does anyone know of other
> fixed pervasive role (perhaps machine specific) registers
> exist?
argument & return value registers come to mind. Registers which are in a class
by themselves (think HILO on mips, shift count registers and the like). The
return pointer may be another worth worrying about.
jeff