From: Denys Vlasenko <vda.linux@googlemail.com>
Date: Thu, 19 Jan 2017 15:45:41 +0000 (+0100)
Subject: tls: fix ROL/ROR x86 optimization
X-Git-Tag: 1_27_0~202
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=f7806f9d8fc889f1d6cd365b69d9d99a4a5a6e26;p=oweals%2Fbusybox.git
tls: fix ROL/ROR x86 optimization
ALWAYS_INLINE:
function old new delta
psAesInitKey 825 824 -1
ROR 5 - -5
setup_mix2 148 134 -14
psAesDecryptBlock 1184 1139 -45
psAesEncryptBlock 1193 1102 -91
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 0/4 up/down: 0/-156) Total: -156 bytes
ALWAYS_INLINE + __builtin_constant_p(shift_cnt):
function old new delta
ROR 5 - -5
psAesInitKey 825 818 -7
setup_mix2 148 123 -25
psAesDecryptBlock 1184 1078 -106
psAesEncryptBlock 1193 1017 -176
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 0/4 up/down: 0/-319) Total: -319 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
---
diff --git a/networking/tls_symmetric.h b/networking/tls_symmetric.h
index b6b55c78c..8488b437e 100644
--- a/networking/tls_symmetric.h
+++ b/networking/tls_symmetric.h
@@ -7,9 +7,6 @@
/* The part below is a section of matrixssl-3-7-2b-open/crypto/cryptolib.h
* Changes are flagged with //bbox
- * TODO:
- * Take a look at "roll %%cl" part... rotates by constant use fewer registers,
- * and on many Intel CPUs rotates by %cl are slower: they take 2 cycles, not 1.
*/
/******************************************************************************/
@@ -28,16 +25,28 @@
#elif defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)) && \
!defined(INTEL_CC) && !defined(PS_NO_ASM)
-static inline unsigned ROL(unsigned word, int i)
+static ALWAYS_INLINE unsigned ROL(unsigned word, int i)
{
+ if (__builtin_constant_p(i)) //box
+ // Rotates by constant use fewer registers,
+ // and on many Intel CPUs rotates by %cl take 2 cycles, not 1.
+ asm ("roll %2,%0" //box
+ :"=r" (word)
+ :"0" (word),"i" (i));
+ else //box
asm ("roll %%cl,%0"
:"=r" (word)
:"0" (word),"c" (i));
return word;
}
-static inline unsigned ROR(unsigned word, int i)
+static ALWAYS_INLINE unsigned ROR(unsigned word, int i)
{
+ if (__builtin_constant_p(i)) //box
+ asm ("rorl %2,%0" //box
+ :"=r" (word)
+ :"0" (word),"i" (i));
+ else //box
asm ("rorl %%cl,%0"
:"=r" (word)
:"0" (word),"c" (i));