On Fri, Jun 08, 2018 at 01:45:13PM +0200, Gabriel Paubert wrote: > On Fri, Jun 08, 2018 at 10:20:41AM +0000, Christophe Leroy wrote: > > + rlwinm. r8, r9, 0, 0xff000000 > > + beq 20f > > + rlwinm. r8, r9, 0, 0x00ff0000 > > + beq 21f > > + rlwinm. r8, r9, 0, 0x0000ff00 > > + beq 22f > > +23: subf r3, r3, r10 > > Actually these rlwinm. can likely be replaced by a single > cntlzw /cntlzd; for 32 bit something like: > > cntlzw r8,r9 > subf r3,r3,r10 > srwi r8,r8,3 > add r3,r3,r8 > blr
The code is finding the first zero byte in the word, not how many leading zero bytes there are. Segher
