ppc: Use vaddcuw instruction.

diff --git a/ChangeLog b/ChangeLog
index 7659795092ad035a0a48512a6a95fd2bf551d898..82de3a48172cb5e7668f6e2eaa43a30e408cb31f 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2020-11-28  Niels Möller  <nisse@lysator.liu.se>
 
+       * powerpc64/p7/chacha-2core.asm: Simplify counter carry handling
+       using the vaddcuw instruction.
+
        Merge changes by Marco Bodrato and Torbjorn Granlund, from the
        gmp/mini-gmp copy of this file.
        * run-tests: Delete special handling of zero arguments. Update

diff --git a/powerpc64/p7/chacha-2core.asm b/powerpc64/p7/chacha-2core.asm
index 265918b604c96bf0831a7558bf4d295eca8a016d..4d4f49064321048fe04cab2e38d1893b412186f2 100644 (file)
--- a/powerpc64/p7/chacha-2core.asm
+++ b/powerpc64/p7/chacha-2core.asm
@@ -73,9 +73,7 @@ PROLOGUE(_nettle_chacha_2core)
 
        lxvw4x  VSR(X3), r8, SRC
 
-       vsubuwm X0, X0, X1      C {-1,0,...,0}
-       vcmpequw Y3, X3, X0
-       vand    Y3, Y3, X1      C Counter carry out
+       vaddcuw Y3, X3, X1      C Counter carry out
        vsldoi  Y3, Y3, Y3, 12
        vor     Y3, Y3, X1