From 892bb11e4eb1e2fa931e2e4f5268dafb848c87db Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Thu, 27 Aug 2015 07:57:36 -0700 Subject: Move i486/strlen.S to strlen.S Since glibc doesn't support i386 any more, we can move i486/strlen.S to strlen.S. * sysdeps/i386/i486/strlen.S: Moved to ... * sysdeps/i386/strlen.S: Here. --- sysdeps/i386/i486/strlen.S | 132 --------------------------------------------- sysdeps/i386/strlen.S | 132 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 132 insertions(+), 132 deletions(-) delete mode 100644 sysdeps/i386/i486/strlen.S create mode 100644 sysdeps/i386/strlen.S (limited to 'sysdeps/i386') diff --git a/sysdeps/i386/i486/strlen.S b/sysdeps/i386/i486/strlen.S deleted file mode 100644 index fa0e0fe..0000000 --- a/sysdeps/i386/i486/strlen.S +++ /dev/null @@ -1,132 +0,0 @@ -/* strlen(str) -- determine the length of the string STR. - Optimized for Intel 80x86, x>=4. - Copyright (C) 1991-2015 Free Software Foundation, Inc. - Contributed by Ulrich Drepper . - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - . */ - -#include -#include "asm-syntax.h" - -#define PARMS 4 /* no space for saved regs */ -#define STR PARMS - - .text -ENTRY (strlen) - - movl STR(%esp), %ecx - movl %ecx, %eax /* duplicate it */ - - andl $3, %ecx /* mask alignment bits */ - jz L(1) /* aligned => start loop */ - cmpb %ch, (%eax) /* is byte NUL? */ - je L(2) /* yes => return */ - incl %eax /* increment pointer */ - - xorl $3, %ecx /* was alignment = 3? */ - jz L(1) /* yes => now it is aligned and start loop */ - cmpb %ch, (%eax) /* is byte NUL? */ - je L(2) /* yes => return */ - addl $1, %eax /* increment pointer */ - - subl $1, %ecx /* was alignment = 2? */ - jz L(1) /* yes => now it is aligned and start loop */ - cmpb %ch, (%eax) /* is byte NUL? */ - je L(2) /* yes => return */ - -/* Don't change the above `addl $1,%eax' and `subl $1, %ecx' into `incl %eax' - and `decl %ecx' resp. The additional two byte per instruction make the - label 4 to be aligned on a 16 byte boundary with nops. - - The following `sub $15, %eax' is part of this trick, too. Together with - the next instruction (`addl $16, %eax') it is in fact a `incl %eax', just - as expected from the algorithm. But doing so has the advantage that - no jump to label 1 is necessary and so the pipeline is not flushed. */ - - subl $15, %eax /* effectively +1 */ - - -L(4): addl $16, %eax /* adjust pointer for full loop */ - -L(1): movl (%eax), %ecx /* get word (= 4 bytes) in question */ - movl $0xfefefeff, %edx /* magic value */ - addl %ecx, %edx /* add the magic value to the word. We get - carry bits reported for each byte which - is *not* 0 */ - jnc L(3) /* highest byte is NUL => return pointer */ - xorl %ecx, %edx /* (word+magic)^word */ - orl $0xfefefeff, %edx /* set all non-carry bits */ - incl %edx /* add 1: if one carry bit was *not* set - the addition will not result in 0. */ - jnz L(3) /* found NUL => return pointer */ - - movl 4(%eax), %ecx /* get word (= 4 bytes) in question */ - movl $0xfefefeff, %edx /* magic value */ - addl %ecx, %edx /* add the magic value to the word. We get - carry bits reported for each byte which - is *not* 0 */ - jnc L(5) /* highest byte is NUL => return pointer */ - xorl %ecx, %edx /* (word+magic)^word */ - orl $0xfefefeff, %edx /* set all non-carry bits */ - incl %edx /* add 1: if one carry bit was *not* set - the addition will not result in 0. */ - jnz L(5) /* found NUL => return pointer */ - - movl 8(%eax), %ecx /* get word (= 4 bytes) in question */ - movl $0xfefefeff, %edx /* magic value */ - addl %ecx, %edx /* add the magic value to the word. We get - carry bits reported for each byte which - is *not* 0 */ - jnc L(6) /* highest byte is NUL => return pointer */ - xorl %ecx, %edx /* (word+magic)^word */ - orl $0xfefefeff, %edx /* set all non-carry bits */ - incl %edx /* add 1: if one carry bit was *not* set - the addition will not result in 0. */ - jnz L(6) /* found NUL => return pointer */ - - movl 12(%eax), %ecx /* get word (= 4 bytes) in question */ - movl $0xfefefeff, %edx /* magic value */ - addl %ecx, %edx /* add the magic value to the word. We get - carry bits reported for each byte which - is *not* 0 */ - jnc L(7) /* highest byte is NUL => return pointer */ - xorl %ecx, %edx /* (word+magic)^word */ - orl $0xfefefeff, %edx /* set all non-carry bits */ - incl %edx /* add 1: if one carry bit was *not* set - the addition will not result in 0. */ - jz L(4) /* no NUL found => continue loop */ - -L(7): addl $4, %eax /* adjust pointer */ -L(6): addl $4, %eax -L(5): addl $4, %eax - -L(3): testb %cl, %cl /* is first byte NUL? */ - jz L(2) /* yes => return */ - incl %eax /* increment pointer */ - - testb %ch, %ch /* is second byte NUL? */ - jz L(2) /* yes => return */ - incl %eax /* increment pointer */ - - testl $0xff0000, %ecx /* is third byte NUL? */ - jz L(2) /* yes => return pointer */ - incl %eax /* increment pointer */ - -L(2): subl STR(%esp), %eax /* compute difference to string start */ - - ret -END (strlen) -libc_hidden_builtin_def (strlen) diff --git a/sysdeps/i386/strlen.S b/sysdeps/i386/strlen.S new file mode 100644 index 0000000..fa0e0fe --- /dev/null +++ b/sysdeps/i386/strlen.S @@ -0,0 +1,132 @@ +/* strlen(str) -- determine the length of the string STR. + Optimized for Intel 80x86, x>=4. + Copyright (C) 1991-2015 Free Software Foundation, Inc. + Contributed by Ulrich Drepper . + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include "asm-syntax.h" + +#define PARMS 4 /* no space for saved regs */ +#define STR PARMS + + .text +ENTRY (strlen) + + movl STR(%esp), %ecx + movl %ecx, %eax /* duplicate it */ + + andl $3, %ecx /* mask alignment bits */ + jz L(1) /* aligned => start loop */ + cmpb %ch, (%eax) /* is byte NUL? */ + je L(2) /* yes => return */ + incl %eax /* increment pointer */ + + xorl $3, %ecx /* was alignment = 3? */ + jz L(1) /* yes => now it is aligned and start loop */ + cmpb %ch, (%eax) /* is byte NUL? */ + je L(2) /* yes => return */ + addl $1, %eax /* increment pointer */ + + subl $1, %ecx /* was alignment = 2? */ + jz L(1) /* yes => now it is aligned and start loop */ + cmpb %ch, (%eax) /* is byte NUL? */ + je L(2) /* yes => return */ + +/* Don't change the above `addl $1,%eax' and `subl $1, %ecx' into `incl %eax' + and `decl %ecx' resp. The additional two byte per instruction make the + label 4 to be aligned on a 16 byte boundary with nops. + + The following `sub $15, %eax' is part of this trick, too. Together with + the next instruction (`addl $16, %eax') it is in fact a `incl %eax', just + as expected from the algorithm. But doing so has the advantage that + no jump to label 1 is necessary and so the pipeline is not flushed. */ + + subl $15, %eax /* effectively +1 */ + + +L(4): addl $16, %eax /* adjust pointer for full loop */ + +L(1): movl (%eax), %ecx /* get word (= 4 bytes) in question */ + movl $0xfefefeff, %edx /* magic value */ + addl %ecx, %edx /* add the magic value to the word. We get + carry bits reported for each byte which + is *not* 0 */ + jnc L(3) /* highest byte is NUL => return pointer */ + xorl %ecx, %edx /* (word+magic)^word */ + orl $0xfefefeff, %edx /* set all non-carry bits */ + incl %edx /* add 1: if one carry bit was *not* set + the addition will not result in 0. */ + jnz L(3) /* found NUL => return pointer */ + + movl 4(%eax), %ecx /* get word (= 4 bytes) in question */ + movl $0xfefefeff, %edx /* magic value */ + addl %ecx, %edx /* add the magic value to the word. We get + carry bits reported for each byte which + is *not* 0 */ + jnc L(5) /* highest byte is NUL => return pointer */ + xorl %ecx, %edx /* (word+magic)^word */ + orl $0xfefefeff, %edx /* set all non-carry bits */ + incl %edx /* add 1: if one carry bit was *not* set + the addition will not result in 0. */ + jnz L(5) /* found NUL => return pointer */ + + movl 8(%eax), %ecx /* get word (= 4 bytes) in question */ + movl $0xfefefeff, %edx /* magic value */ + addl %ecx, %edx /* add the magic value to the word. We get + carry bits reported for each byte which + is *not* 0 */ + jnc L(6) /* highest byte is NUL => return pointer */ + xorl %ecx, %edx /* (word+magic)^word */ + orl $0xfefefeff, %edx /* set all non-carry bits */ + incl %edx /* add 1: if one carry bit was *not* set + the addition will not result in 0. */ + jnz L(6) /* found NUL => return pointer */ + + movl 12(%eax), %ecx /* get word (= 4 bytes) in question */ + movl $0xfefefeff, %edx /* magic value */ + addl %ecx, %edx /* add the magic value to the word. We get + carry bits reported for each byte which + is *not* 0 */ + jnc L(7) /* highest byte is NUL => return pointer */ + xorl %ecx, %edx /* (word+magic)^word */ + orl $0xfefefeff, %edx /* set all non-carry bits */ + incl %edx /* add 1: if one carry bit was *not* set + the addition will not result in 0. */ + jz L(4) /* no NUL found => continue loop */ + +L(7): addl $4, %eax /* adjust pointer */ +L(6): addl $4, %eax +L(5): addl $4, %eax + +L(3): testb %cl, %cl /* is first byte NUL? */ + jz L(2) /* yes => return */ + incl %eax /* increment pointer */ + + testb %ch, %ch /* is second byte NUL? */ + jz L(2) /* yes => return */ + incl %eax /* increment pointer */ + + testl $0xff0000, %ecx /* is third byte NUL? */ + jz L(2) /* yes => return pointer */ + incl %eax /* increment pointer */ + +L(2): subl STR(%esp), %eax /* compute difference to string start */ + + ret +END (strlen) +libc_hidden_builtin_def (strlen) -- cgit v1.1