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From: Uros Bizjak <ubizjak@gmail.com>
To: linux-crypto@vger.kernel.org, x86@kernel.org
Cc: Uros Bizjak <ubizjak@gmail.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>
Subject: [PATCH] crypto: x86/sha512-intel: Use TEST %reg,%reg instead of CMP $0,%reg
Date: Fri, 27 Nov 2020 10:59:43 +0100	[thread overview]
Message-ID: <20201127095943.62292-1-ubizjak@gmail.com> (raw)

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/sha512-avx-asm.S   | 2 +-
 arch/x86/crypto/sha512-ssse3-asm.S | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/crypto/sha512-avx-asm.S b/arch/x86/crypto/sha512-avx-asm.S
index 63470fd6ae32..684d58c8bc4f 100644
--- a/arch/x86/crypto/sha512-avx-asm.S
+++ b/arch/x86/crypto/sha512-avx-asm.S
@@ -278,7 +278,7 @@ frame_size = frame_GPRSAVE + GPRSAVE_SIZE
 # "blocks" is the message length in SHA512 blocks
 ########################################################################
 SYM_FUNC_START(sha512_transform_avx)
-	cmp $0, msglen
+	test msglen, msglen
 	je nowork
 
 	# Allocate Stack Space
diff --git a/arch/x86/crypto/sha512-ssse3-asm.S b/arch/x86/crypto/sha512-ssse3-asm.S
index 7946a1bee85b..50812af0b083 100644
--- a/arch/x86/crypto/sha512-ssse3-asm.S
+++ b/arch/x86/crypto/sha512-ssse3-asm.S
@@ -280,7 +280,7 @@ frame_size = frame_GPRSAVE + GPRSAVE_SIZE
 ########################################################################
 SYM_FUNC_START(sha512_transform_ssse3)
 
-	cmp $0, msglen
+	test msglen, msglen
 	je nowork
 
 	# Allocate Stack Space
-- 
2.26.2


             reply	other threads:[~2020-11-27 10:00 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-27  9:59 Uros Bizjak [this message]
2020-12-04  7:15 ` [PATCH] crypto: x86/sha512-intel: Use TEST %reg,%reg instead of CMP $0,%reg Herbert Xu

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