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glibc/sysdeps/i386/strtok.S

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/* strtok (str, delim) -- Return next DELIM separated token from STR.
For Intel 80x86, x>=3.
Copyright (C) 1996-1998,2000,2001,2005,2006 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
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. */
#include <sysdep.h>
#include "asm-syntax.h"
#include "bp-sym.h"
#include "bp-asm.h"
/* This file can be used for three variants of the strtok function:
strtok:
INPUT PARAMETER:
str (sp + 4)
delim (sp + 8)
strtok_r:
INPUT PARAMETER:
str (sp + 4)
delim (sp + 8)
save_ptr (sp + 12)
We do a common implementation here. */
#ifdef USE_AS_STRTOK_R
# define SAVE_PTR 0(%ecx)
#else
.bss
.local save_ptr
ASM_TYPE_DIRECTIVE (save_ptr, @object)
.size save_ptr, 4
save_ptr:
# if __BOUNDED_POINTERS__
.space 12
# else
.space 4
# endif
# ifdef PIC
# define SAVE_PTR save_ptr@GOTOFF(%ebx)
# else
# define SAVE_PTR save_ptr
# endif
# define FUNCTION strtok
#endif
#define PARMS LINKAGE /* no space for saved regs */
#define RTN PARMS
#define STR RTN+RTN_SIZE
#define DELIM STR+PTR_SIZE
#define SAVE DELIM+PTR_SIZE
.text
ENTRY (BP_SYM (FUNCTION))
ENTER
movl STR(%esp), %edx
movl DELIM(%esp), %eax
CHECK_BOUNDS_LOW (%eax, DELIM(%esp))
#if !defined USE_AS_STRTOK_R && defined PIC
pushl %ebx /* Save PIC register. */
cfi_adjust_cfa_offset (4)
call L(here)
cfi_adjust_cfa_offset (4)
cfi_rel_offset (ebx, 0)
L(here):
popl %ebx
cfi_adjust_cfa_offset (-4)
addl $_GLOBAL_OFFSET_TABLE_+[.-L(here)], %ebx
#endif
/* If the pointer is NULL we have to use the stored value of
the last run. */
cmpl $0, %edx
#if __BOUNDED_POINTERS__
movl SAVE(%esp), %ecx
je L(0)
/* Save bounds of incoming non-NULL STR into save area. */
movl 4+STR(%esp), %eax
movl %eax, 4+SAVE_PTR
movl 8+STR(%esp), %eax
movl %eax, 8+SAVE_PTR
CHECK_BOUNDS_LOW (%edx, SAVE_PTR)
jmp L(1)
L(0): movl SAVE_PTR, %edx
CHECK_BOUNDS_LOW (%edx, SAVE_PTR)
jmp L(1)
#else
jne L(1)
#endif
#ifdef USE_AS_STRTOK_R
/* The value is stored in the third argument. */
movl SAVE(%esp), %edx
movl (%edx), %edx
#else
/* The value is in the local variable defined above. But
we have to take care for PIC code. */
movl SAVE_PTR, %edx
#endif
testl %edx, %edx
jz L(returnNULL)
L(1):
/* First we create a table with flags for all possible characters.
For the ASCII (7bit/8bit) or ISO-8859-X character sets which are
supported by the C string functions we have 256 characters.
Before inserting marks for the stop characters we clear the whole
table. The unrolled form is much faster than a loop. */
xorl %ecx, %ecx /* %ecx = 0 !!! */
pushl %ecx /* make a 256 bytes long block filled with 0 */
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl %ecx
cfi_adjust_cfa_offset (4)
pushl $0 /* These immediate values make the label 2 */
cfi_adjust_cfa_offset (4)
pushl $0 /* to be aligned on a 16 byte boundary to */
cfi_adjust_cfa_offset (4)
pushl $0 /* get a better performance of the loop. */
cfi_adjust_cfa_offset (4)
pushl $0
cfi_adjust_cfa_offset (4)
pushl $0
cfi_adjust_cfa_offset (4)
pushl $0
cfi_adjust_cfa_offset (4)
/* For understanding the following code remember that %ecx == 0 now.
Although all the following instruction only modify %cl we always
have a correct zero-extended 32-bit value in %ecx. */
L(2): movb (%eax), %cl /* get byte from stopset */
testb %cl, %cl /* is NUL char? */
jz L(1_1) /* yes => start compare loop */
movb %cl, (%esp,%ecx) /* set corresponding byte in stopset table */
movb 1(%eax), %cl /* get byte from stopset */
testb $0xff, %cl /* is NUL char? */
jz L(1_2) /* yes => start compare loop */
movb %cl, (%esp,%ecx) /* set corresponding byte in stopset table */
movb 2(%eax), %cl /* get byte from stopset */
testb $0xff, %cl /* is NUL char? */
jz L(1_3) /* yes => start compare loop */
movb %cl, (%esp,%ecx) /* set corresponding byte in stopset table */
movb 3(%eax), %cl /* get byte from stopset */
addl $4, %eax /* increment stopset pointer */
movb %cl, (%esp,%ecx) /* set corresponding byte in stopset table */
testb $0xff, %cl /* is NUL char? */
jnz L(2) /* no => process next dword from stopset */
#if __BOUNDED_POINTERS__
jmp L(1_0) /* pointer is correct for bounds check */
L(1_3): incl %eax /* adjust pointer for bounds check */
L(1_2): incl %eax /* ditto */
L(1_1): incl %eax /* ditto */
L(1_0): CHECK_BOUNDS_HIGH (%eax, DELIM(%esp), jbe)
#else
L(1_3):; L(1_2):; L(1_1): /* fall through */
#endif
leal -4(%edx), %eax /* prepare loop */
/* We use a neat trick for the following loop. Normally we would
have to test for two termination conditions
1. a character in the stopset was found
and
2. the end of the string was found
As a sign that the character is in the stopset we store its
value in the table. The value of NUL is NUL so the loop
terminates for NUL in every case. */
L(3): addl $4, %eax /* adjust pointer for full loop round */
movb (%eax), %cl /* get byte from string */
testb %cl, (%esp,%ecx) /* is it contained in stopset? */
jz L(4) /* no => start of token */
movb 1(%eax), %cl /* get byte from string */
testb %cl, (%esp,%ecx) /* is it contained in stopset? */
jz L(5) /* no => start of token */
movb 2(%eax), %cl /* get byte from string */
testb %cl, (%esp,%ecx) /* is it contained in stopset? */
jz L(6) /* no => start of token */
movb 3(%eax), %cl /* get byte from string */
testb %cl, (%esp,%ecx) /* is it contained in stopset? */
jnz L(3) /* yes => start of loop */
incl %eax /* adjust pointer */
L(6): incl %eax
L(5): incl %eax
/* Now we have to terminate the string. */
L(4): leal -4(%eax), %edx /* We use %EDX for the next run. */
L(7): addl $4, %edx /* adjust pointer for full loop round */
movb (%edx), %cl /* get byte from string */
cmpb %cl, (%esp,%ecx) /* is it contained in skipset? */
je L(8) /* yes => return */
movb 1(%edx), %cl /* get byte from string */
cmpb %cl, (%esp,%ecx) /* is it contained in skipset? */
je L(9) /* yes => return */
movb 2(%edx), %cl /* get byte from string */
cmpb %cl, (%esp,%ecx) /* is it contained in skipset? */
je L(10) /* yes => return */
movb 3(%edx), %cl /* get byte from string */
cmpb %cl, (%esp,%ecx) /* is it contained in skipset? */
jne L(7) /* no => start loop again */
incl %edx /* adjust pointer */
L(10): incl %edx
L(9): incl %edx
L(8): /* Remove the stopset table. */
addl $256, %esp
cfi_adjust_cfa_offset (-256)
cmpl %eax, %edx
je L(returnNULL) /* There was no token anymore. */
movb $0, (%edx) /* Terminate string. */
/* Are we at end of string? */
cmpb $0, %cl
je L(11)
incl %edx
L(11):
/* Store the pointer to the next character. */
#ifdef USE_AS_STRTOK_R
movl SAVE(%esp), %ecx
#endif
movl %edx, SAVE_PTR
CHECK_BOUNDS_HIGH (%edx, SAVE_PTR, jb)
RETURN_BOUNDED_POINTER (SAVE_PTR)
L(epilogue):
#if !defined USE_AS_STRTOK_R && defined PIC
popl %ebx
cfi_adjust_cfa_offset (-4)
cfi_restore (ebx)
#endif
LEAVE
RET_PTR
L(returnNULL):
xorl %eax, %eax
#ifdef USE_AS_STRTOK_R
movl SAVE(%esp), %ecx
#endif
movl %edx, SAVE_PTR
RETURN_NULL_BOUNDED_POINTER
jmp L(epilogue)
END (BP_SYM (FUNCTION))
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