On Thu, 2014-11-27 at 10:08 -0600, Segher Boessenkool wrote: > On Wed, Nov 26, 2014 at 05:50:27PM -0600, Peter Bergner wrote: > > Nope, you don't get a SIGILL when executing 64-bit instructions in > > 32-bit mode, so it'll happily just execute the instruction, doing > > a full 64-bit compare. I'm guessing that the upper 32-bits of both > > r3 and r4 contain zeros, so we're probably just getting lucky. > > You will get a SIGILL if you run on 32-bit hardware.
Ha, I completely forgot about 32-bit hardware. Anyway, I looked at the ISA, and cmpdi and cmpwi are just extended mnemonics for cmpi, with cmpdi setting the L field to 1. Probably on 32-bit hardware, the hardware is just ignoring the L bit being set and doing a cmpwi for us??? Peter _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
