This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: handling of FIXED_REGISTERS
Olatunji Ruwase <tjruwase@transmeta.com> writes:
> Therefore it is possible to use sp in inline assembly as follows,
> register int foo asm("sp")
> allowing the programmer code to clobber "sp" arbitrarily.
> While I cant think of any useful reason to write code of such nature, I m
> curious as to why gcc is designed not to reject it.
There is nothing wrong with using a fixed register for a register
variable, as long as you know what you do. Moreover, you can mark
additional registers as fixed with -ffixed-<reg> and use it for your own
special purpose.
Andreas.
--
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux AG, Maxfeldstraße 5, 90409 Nürnberg, Germany
Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."