On Tue, Sep 19, 2023 at 02:35:25PM +0000, David Laight wrote: > From: Matthew Wilcox <willy@xxxxxxxxxxxxx> > > Sent: 19 September 2023 15:26 > > > > On Tue, Sep 19, 2023 at 01:23:08PM +0000, David Laight wrote: > > > > Well, that sucks. What do you suggest for Coldfire? > > > > > > Can you just do a 32bit xor ? > > > Unless you've got smp m68k I'd presume it is ok? > > > (And assuming you aren't falling off a page.) > > > > Patch welcome. > > My 68020 book seems to be at work and I'm at home. > (The 286, 386 and cy7c600 (sparc 32) books don't help). > > But if the code is trying to do *ptr ^= 0x80 and check the > sign flag then you just need to use eor.l with 0x80000000 > on the same address. I have a 68020 book; what I don't have is a Coldfire manual. Anyway, that's not the brief. We're looking to (eg) clear bit 0 and test whether bit 7 was set. So it's the sign bit of the byte, not the sign bit of the int.
