On Fri, Jul 03, 2009 at 10:57:12PM +0200, Andreas Schwab wrote: > Brad Boyer <flar@xxxxxxxxxxxxx> writes: > > > On Fri, Jul 03, 2009 at 12:14:41PM +0530, kernel mailz wrote: > >> b. using m or Z with a memory address. I tried replacing m/Z but no change > >> Is there some guideline ? > >> gcc documentation says Z is obsolete. Is m/Z replaceable ? > > > > No idea. I don't remember ever seeing 'Z' used in anything. Maybe somebody > > else remembers what it used to mean. > > The 'Z' constraint is required for a memory operand for insns that don't > have an update form (which would be selected by the %U modifier). Hmmm, I believed that it was for instructions that only have an indexed form (all Altivec, byte reverse, and l?arx/st?cx for atomic operations). Of course none of these instructions have an update form, but they don't have an offset encoded in the instruction either. Gabriel
