poly1305: cleanup ppc64le R0/$0 usage
There is some implicit R0 == $0 here which may not be desired.
"CMP $0, Rx" translates to "cmpd r0, rX" which is less preferred
than "cmpdi r0, 0". Likewise, "ADDE $0, Rx" also turns into
"adde R0, Rx, Rx" which can be simplified to a similar instruction
which adds to zero with carry, "ADDZE Rx, Rx".
Change-Id: I5de17ff5b02c7c9d57daf014c7fe9420bfbeeeab
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/311372
Reviewed-by: Carlos Eduardo Seo <carlos.seo@linaro.org>
Trust: Carlos Eduardo Seo <carlos.seo@linaro.org>
Trust: Lynn Boger <laboger@linux.vnet.ibm.com>
diff --git a/poly1305/sum_ppc64le.s b/poly1305/sum_ppc64le.s
index 5cd7494..3cede53 100644
--- a/poly1305/sum_ppc64le.s
+++ b/poly1305/sum_ppc64le.s
@@ -82,7 +82,7 @@
BGE loop
bytes_between_0_and_15:
- CMP $0, R5
+ CMP R5, $0
BEQ done
MOVD $0, R16 // h0
MOVD $0, R17 // h1
@@ -122,7 +122,7 @@
// Exactly 8
MOVD (R4), R16
- CMP $0, R17
+ CMP R17, $0
// Check if we've already set R17; if not
// set 1 to indicate end of msg.
@@ -151,7 +151,7 @@
ADD $2, R4
less2:
- CMP $0, R5
+ CMP R5, $0
BEQ insert1
MOVBZ (R4), R21
SLD R22, R21, R21
@@ -166,12 +166,12 @@
carry:
// Add new values to h0, h1, h2
- ADDC R16, R8
- ADDE R17, R9
- ADDE $0, R10
- MOVD $16, R5
- ADD R5, R4
- BR multiply
+ ADDC R16, R8
+ ADDE R17, R9
+ ADDZE R10, R10
+ MOVD $16, R5
+ ADD R5, R4
+ BR multiply
done:
// Save h0, h1, h2 in state
