glibc/sysdeps/i386/stpcpy.S
Siddhesh Poyarekar 30891f35fa Remove "Contributed by" lines
We stopped adding "Contributed by" or similar lines in sources in 2012
in favour of git logs and keeping the Contributors section of the
glibc manual up to date.  Removing these lines makes the license
header a bit more consistent across files and also removes the
possibility of error in attribution when license blocks or files are
copied across since the contributed-by lines don't actually reflect
reality in those cases.

Move all "Contributed by" and similar lines (Written by, Test by,
etc.) into a new file CONTRIBUTED-BY to retain record of these
contributions.  These contributors are also mentioned in
manual/contrib.texi, so we just maintain this additional record as a
courtesy to the earlier developers.

The following scripts were used to filter a list of files to edit in
place and to clean up the CONTRIBUTED-BY file respectively.  These
were not added to the glibc sources because they're not expected to be
of any use in future given that this is a one time task:

https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc
https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-09-03 22:06:44 +05:30

88 lines
2.6 KiB
ArmAsm

/* Copy SRC to DEST returning the address of the terminating '\0' in DEST.
For Intel 80x86, x>=3.
Copyright (C) 1994-2021 Free Software Foundation, Inc.
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
<https://www.gnu.org/licenses/>. */
/* This function is defined neither in ANSI nor POSIX standards but is
also not invented here. */
#include <sysdep.h>
#include "asm-syntax.h"
#define PARMS 4 /* no space for saved regs */
#define RTN PARMS
#define DEST RTN
#define SRC DEST+4
.text
ENTRY (__stpcpy)
movl DEST(%esp), %eax
movl SRC(%esp), %ecx
subl %eax, %ecx /* magic: reduce number of loop variants
to one using addressing mode */
/* Here we would like to write
subl $4, %eax
ALIGN (4)
but the assembler is too smart and optimizes for the shortest
form where the number only needs one byte. But if we could
have the long form we would not need the alignment. */
.byte 0x81, 0xe8 /* This is `subl $0x00000004, %eax' */
.long 0x00000004
/* Four times unfolded loop with only one loop counter. This
is achieved by the use of index+base addressing mode. As the
loop counter we use the destination address because this is
also the result. */
L(1): addl $4, %eax /* increment loop counter */
movb (%eax,%ecx), %dl /* load current char */
movb %dl, (%eax) /* and store it */
testb %dl, %dl /* was it NUL? */
jz L(2) /* yes, then exit */
movb 1(%eax,%ecx), %dl /* load current char */
movb %dl, 1(%eax) /* and store it */
testb %dl, %dl /* was it NUL? */
jz L(3) /* yes, then exit */
movb 2(%eax,%ecx), %dl /* load current char */
movb %dl, 2(%eax) /* and store it */
testb %dl, %dl /* was it NUL? */
jz L(4) /* yes, then exit */
movb 3(%eax,%ecx), %dl /* load current char */
movb %dl, 3(%eax) /* and store it */
testb %dl, %dl /* was it NUL? */
jnz L(1) /* no, then continue loop */
incl %eax /* correct loop counter */
L(4): incl %eax
L(3): incl %eax
L(2):
ret
END (__stpcpy)
weak_alias (__stpcpy, stpcpy)
libc_hidden_def (__stpcpy)
libc_hidden_builtin_def (stpcpy)