"Marco Bodrato" <bodr...@mail.dm.unipi.it> writes:
I saw this change go in:
diff -r 118627eed635 -r bb86e66536d5 mpn/x86_64/coreihwl/gcd_11.asm
--- a/mpn/x86_64/coreihwl/gcd_11.asm Tue Aug 13 22:20:06 2019 +0200
+++ b/mpn/x86_64/coreihwl/gcd_11.asm Wed Aug 14 01:06:08 2019 +0200
@@ -79,10 +79,10 @@
ALIGN(16) C
L(top): bsf v0, %rcx C
+ mov u0, %r9 C
sub %rax, u0 C u - v
cmovc v0, u0 C u = |u - v|
cmovc %r9, %rax C v = min(u,v)
- shrx( %rcx, u0, %r9) C
shrx( %rcx, u0, u0) C
mov %rax, v0 C
sub u0, v0 C v - u
What's the purpose of this change?
Did you time it on hwl, bwl, skl to make sure it's not slower than the
changed code?
The double shrx was not a mistake; it sped things up quite a bit.
(I use the same trick for zen and zen2.)
--
Torbjörn
Please encrypt, key id 0xC8601622
_______________________________________________
gmp-devel mailing list
gmp-devel@gmplib.org
https://gmplib.org/mailman/listinfo/gmp-devel
