On Mon, Apr 12, 2021 at 05:02:38PM -0500, will schmidt wrote: > On Fri, 2021-04-09 at 17:09 -0400, Michael Meissner wrote: > > - li r8,trampoline_size /* verify that the trampoline is big > > enough */ > > - cmpw cr1,r8,r4 > > + cmpwi cr1,r4,trampoline_size /* verify that the trampoline is big > > enough */ > > Hmm, I spent several minutes trying to determine how cmpw behaves > differently than cmpwi before noticing you also swapped the > order of the r4,r8 operands. > > That seems OK. > > A statement in the description indicating that you used a cmpwi instead > of a cmpw since you were in the neighborhood would help call that out.
In general, don't do two unrelated things, esp. when not pointing it out explicitly. > The #elif _CALL_ELF == 2 portion of tramp.S (line 159 or so) has a > similar compare stanza with respect to the order of operands on the > compare. Will this also have a backwards greater-than less-than issue? > > li r8,trampoline_size /* verify that the trampoline is big > enough */ > cmpw cr1,r8,r4 > srwi r4,r4,3 /* # doublewords to move */ > addi r9,r3,-8 /* adjust pointer for stdu */ > mtctr r4 > blt cr1,.Labort Not sure... It should use cmpwi as well though, and then it is easier to see. Segher
