* [PATCH] crypto: x86/poly1305-intel: Use TEST %reg,%reg instead of CMP $0,%reg
@ 2020-11-27 10:18 Uros Bizjak
2020-12-04 7:15 ` Herbert Xu
0 siblings, 1 reply; 2+ messages in thread
From: Uros Bizjak @ 2020-11-27 10:18 UTC (permalink / raw)
To: linux-crypto, x86
Cc: Uros Bizjak, Herbert Xu, Borislav Petkov, H. Peter Anvin
CMP $0,%reg can't set overflow flag, so we can use shorter TEST %reg,%reg
instruction when only zero and sign flags are checked (E,L,LE,G,GE conditions).
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
---
arch/x86/crypto/poly1305-x86_64-cryptogams.pl | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/crypto/poly1305-x86_64-cryptogams.pl b/arch/x86/crypto/poly1305-x86_64-cryptogams.pl
index 7d568012cc15..71fae5a09e56 100644
--- a/arch/x86/crypto/poly1305-x86_64-cryptogams.pl
+++ b/arch/x86/crypto/poly1305-x86_64-cryptogams.pl
@@ -251,7 +251,7 @@ $code.=<<___;
mov %rax,8($ctx)
mov %rax,16($ctx)
- cmp \$0,$inp
+ test $inp,$inp
je .Lno_key
___
$code.=<<___ if (!$kernel);
--
2.26.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] crypto: x86/poly1305-intel: Use TEST %reg,%reg instead of CMP $0,%reg
2020-11-27 10:18 [PATCH] crypto: x86/poly1305-intel: Use TEST %reg,%reg instead of CMP $0,%reg Uros Bizjak
@ 2020-12-04 7:15 ` Herbert Xu
0 siblings, 0 replies; 2+ messages in thread
From: Herbert Xu @ 2020-12-04 7:15 UTC (permalink / raw)
To: Uros Bizjak; +Cc: linux-crypto, x86, Borislav Petkov, H. Peter Anvin
On Fri, Nov 27, 2020 at 11:18:12AM +0100, Uros Bizjak wrote:
> CMP $0,%reg can't set overflow flag, so we can use shorter TEST %reg,%reg
> instruction when only zero and sign flags are checked (E,L,LE,G,GE conditions).
>
> Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
> Cc: Herbert Xu <herbert@gondor.apana.org.au>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> ---
> arch/x86/crypto/poly1305-x86_64-cryptogams.pl | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Patch applied. Thanks.
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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2020-11-27 10:18 [PATCH] crypto: x86/poly1305-intel: Use TEST %reg,%reg instead of CMP $0,%reg Uros Bizjak
2020-12-04 7:15 ` Herbert Xu
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