The branch master has been updated
via e72bf967186a2ac26459926a20dbf03dc119eb5b (commit)
from c39e4048b538ec76313c264e860cfb5cd677a9ac (commit)
- Log -----------------------------------------------------------------
commit e72bf967186a2ac26459926a20dbf03dc119eb5b
Author: Andy Polyakov <[email protected]>
Date: Tue Feb 27 19:02:21 2018 +0100
ec/asm/x25519-x86_64.pl: remove redundant carry chain.
Why is it redundant? We're looking at carry from addition of small,
11-bit number to 256-bit one. And carry would mean only one thing,
resulting first limb being small number and remaing ones - zeros.
Hence adding 38 to first limb can't carry.
Reviewed-by: Rich Salz <[email protected]>
(Merged from https://github.com/openssl/openssl/pull/5476)
-----------------------------------------------------------------------
Summary of changes:
crypto/ec/asm/x25519-x86_64.pl | 21 ++++++---------------
1 file changed, 6 insertions(+), 15 deletions(-)
diff --git a/crypto/ec/asm/x25519-x86_64.pl b/crypto/ec/asm/x25519-x86_64.pl
index 9a56939..930d7bd 100755
--- a/crypto/ec/asm/x25519-x86_64.pl
+++ b/crypto/ec/asm/x25519-x86_64.pl
@@ -40,12 +40,12 @@
# P4 +22% +40%
# Sandy Bridge -3% +11%
# Haswell -1% +13%
-# Broadwell(***) +26% +30%
-# Skylake(***) +30% +47%
+# Broadwell(***) +30% +35%
+# Skylake(***) +33% +47%
# Silvermont +20% +26%
# Goldmont +40% +50%
# Bulldozer +20% +9%
-# Ryzen(***) +35% +32%
+# Ryzen(***) +43% +40%
# VIA +170% +120%
#
# (*) amd64-51 is popular assembly implementation with 2^51 radix,
@@ -631,13 +631,10 @@ x25519_fe64_sqr:
and \$38,%rax
add %rax,$acc0
- adc \$0,$acc1
- mov $acc0,8*0(%rdi)
- adc \$0,$acc2
mov $acc1,8*1(%rdi)
- adc \$0,$acc3
mov $acc2,8*2(%rdi)
mov $acc3,8*3(%rdi)
+ mov $acc0,8*0(%rdi)
mov 8*3(%rsp),%r15
mov 8*4(%rsp),%r14
@@ -674,13 +671,10 @@ x25519_fe64_mul121666:
and \$38,%rax
add %rax,$acc0
- adc \$0,$acc1
- mov $acc0,8*0(%rdi)
- adc \$0,$acc2
mov $acc1,8*1(%rdi)
- adc \$0,$acc3
mov $acc2,8*2(%rdi)
mov $acc3,8*3(%rdi)
+ mov $acc0,8*0(%rdi)
ret
.size x25519_fe64_mul121666,.-x25519_fe64_mul121666
@@ -769,14 +763,11 @@ x25519_fe64_tobytes:
and \$19,%rax
add %rax,$acc0
- adc \$0,$acc1
- adc \$0,$acc2
- adc \$0,$acc3
- mov $acc0,8*0(%rdi)
mov $acc1,8*1(%rdi)
mov $acc2,8*2(%rdi)
mov $acc3,8*3(%rdi)
+ mov $acc0,8*0(%rdi)
ret
.size x25519_fe64_tobytes,.-x25519_fe64_tobytes
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