Re: [PATCH] MIPS gas: 64 bit aware rol/ror macros

[Thiemo Seufer <ica2_ts at csv dot ica dot uni-stuttgart dot de>]

cgd@broadcom.com wrote:
> At Sat, 11 May 2002 09:26:22 +0000 (UTC), "Thiemo Seufer" wrote:
> > this extends the rotate macros of MIPS gas to do the right
> > thing for 64 bit registers.
> 
> Personally, I disagree with this.
> 
> Manuals such as See Mips Run document rol/ror to be 32-bit, and add
> drol/dror macros to do 64-bit rotates.  (SMR pages 188-189, 196.)

And immediate rotate macros aren't mentioned there at all. I don't
know how reliable SMR is WRT.

> Further, if you redefine rol/ror to be 64-bit on machines with 64-bit
> GPRs... well, how do you do 32-bit rotates on those machines?

I thought about using drol/dror, but why should someone expect to have
a 32 bit "rotate" of a 64 bit register? It looks like the la/dla
weirdness.

IOW, what would you expect as the result from a 32 bit rotate of
a 64 bit register, especially if the 64 bit value isn't a 32 bit
sign extended one?


Thiemo