t...@gmplib.org (Torbjörn Granlund) writes: > ni...@lysator.liu.se (Niels Möller) writes: > > > Checking u1 = 0 and v1 = 0 separately as you suggest is a different > > thing, and it might not have zero cost in the gcd_22 loop. > > I think only the shifted number should be checked, and as the main loop > exit condition. > > OK, so we agree there!
But on second though, maybe while (u1 | v1) or while (u1 || v1) is even simpler and efficient enough. Then we need not do anything special when the first operand gets small enough to fit in one limb. > That would probably work fine, but maybe not simpler than an explicit > gcd_22. So then the normal case would call gcd_22 with u1 > 0, v1 > 0, > and exit the loop with u1 > 0, v1 == 0. I don't see why we'd need a > right shift here, I think one could just check if u1 > 0 and if so jump > back to gcd_22, and next time the loop exits we will have u1 = 0, v1 = > 0. > > What do you mean by an "explicit gcd_22"? Sorry, I meant "explicit gcd_21". Regards, /Niels -- Niels Möller. PGP-encrypted email is preferred. Keyid 368C6677. Internet email is subject to wholesale government surveillance. _______________________________________________ gmp-devel mailing list gmp-devel@gmplib.org https://gmplib.org/mailman/listinfo/gmp-devel
