mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-18 02:50:09 +00:00
97 lines
3.0 KiB
ArmAsm
97 lines
3.0 KiB
ArmAsm
/* Copy SRC to DEST returning the address of the terminating '\0' in DEST.
|
|
For Intel 80x86, x>=3.
|
|
Copyright (C) 1994,1995,1996,1997,2000,2002 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Ulrich Drepper (drepper@gnu.ai.mit.edu).
|
|
|
|
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, write to the Free
|
|
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
|
|
02111-1307 USA. */
|
|
|
|
/* This function is defined neither in ANSI nor POSIX standards but is
|
|
also not invented here. */
|
|
|
|
#include <sysdep.h>
|
|
#include "asm-syntax.h"
|
|
#include "bp-sym.h"
|
|
#include "bp-asm.h"
|
|
|
|
#define PARMS LINKAGE /* no space for saved regs */
|
|
#define RTN PARMS
|
|
#define DEST RTN+RTN_SIZE
|
|
#define SRC DEST+PTR_SIZE
|
|
|
|
.text
|
|
ENTRY (BP_SYM (__stpcpy))
|
|
ENTER
|
|
|
|
movl DEST(%esp), %eax
|
|
movl SRC(%esp), %ecx
|
|
CHECK_BOUNDS_LOW (%eax, DEST(%esp))
|
|
CHECK_BOUNDS_LOW (%ecx, SRC(%esp))
|
|
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):
|
|
CHECK_BOUNDS_HIGH (%eax, DEST(%esp), jb)
|
|
RETURN_BOUNDED_POINTER (DEST(%esp))
|
|
|
|
LEAVE
|
|
RET_PTR
|
|
END (BP_SYM (__stpcpy))
|
|
|
|
weak_alias (BP_SYM (__stpcpy), BP_SYM (stpcpy))
|
|
libc_hidden_def (__stpcpy)
|