Commit 9a708bf9 authored by Andy Polyakov's avatar Andy Polyakov
Browse files

{arm64|x86_64}cpuid.pl: add special 16-byte case to OPENSSL_memcmp. 



OPENSSL_memcmp is a must in GCM decrypt and general-purpose loop takes
quite a portion of execution time for short inputs, more than GHASH for
few-byte inputs according to profiler. Special 16-byte case takes it off
top five list in profiler output.

Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6312)
parent c1b2569d

crypto/arm64cpuid.pl

+13 −0
Original line number Diff line number Diff line
@@ -115,6 +115,19 @@ OPENSSL_cleanse: 
CRYPTO_memcmp:

	eor	w3,w3,w3

	cbz	x2,.Lno_data	// len==0?

	cmp	x2,#16

	b.ne	.Loop_cmp

	ldp	x8,x9,[x0]

	ldp	x10,x11,[x1]

	eor	x8,x8,x10

	eor	x9,x9,x11

	orr	x8,x8,x9

	mov	x0,#1

	cmp	x8,#0

	csel	x0,xzr,x0,eq

	ret



.align	4

.Loop_cmp:

	ldrb	w4,[x0],#1

	ldrb	w5,[x1],#1

crypto/x86_64cpuid.pl

+12 −0
Original line number Diff line number Diff line
@@ -271,6 +271,18 @@ CRYPTO_memcmp: 
	xor	%r10,%r10

	cmp	\$0,$arg3

	je	.Lno_data

	cmp	\$16,$arg3

	jne	.Loop_cmp

	mov	($arg1),%r10

	mov	8($arg1),%r11

	mov	\$1,$arg3

	xor	($arg2),%r10

	xor	8($arg2),%r11

	or	%r11,%r10

	cmovnz	$arg3,%rax

	ret



.align	16

.Loop_cmp:

	mov	($arg1),%r10b

	lea	1($arg1),$arg1