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/* strtok (str, delim) -- Return next DELIM separated token from STR.
For AMD x86-64.
Copyright (C) 1998-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Based on i686 version contributed by Ulrich Drepper
<drepper@cygnus.com>, 1998.
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
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include "asm-syntax.h"
/* This file can be used for the strtok and strtok_r functions:
strtok:
INPUT PARAMETER:
str %rdi
delim %rsi
strtok_r:
INPUT PARAMETER:
str %rdi
delim %rsi
save_ptr %rdx
We do a common implementation here. */
#ifdef USE_AS_STRTOK_R
# define SAVE_PTR (%r9)
#else
.bss
.local save_ptr
.type save_ptr, @object
.size save_ptr, LP_SIZE
save_ptr:
.space LP_SIZE
# ifdef PIC
# define SAVE_PTR save_ptr(%rip)
# else
# define SAVE_PTR save_ptr
# endif
# define FUNCTION strtok
#endif
.text
ENTRY (FUNCTION)
/* 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. */
movq %rdi, %r8 /* Save value. */
subq $256, %rsp /* Make space for 256 bytes. */
cfi_adjust_cfa_offset(256)
movl $32, %ecx /* 32*8 bytes = 256 bytes. */
movq %rsp, %rdi
xorl %eax, %eax /* We store 0s. */
cld
rep
stosq
/* Note: %rcx = 0 !!! */
#ifdef USE_AS_STRTOK_R
/* The value is stored in the third argument. */
mov %RDX_LP, %R9_LP /* Save value - see def. of SAVE_PTR. */
mov (%rdx), %RAX_LP
#else
/* The value is in the local variable defined above. But
we have to take care for PIC code. */
mov SAVE_PTR, %RAX_LP
#endif
movq %r8, %rdx /* Get start of string. */
/* If the pointer is NULL we have to use the stored value of
the last run. */
cmpq $0, %rdx
cmove %rax, %rdx
testq %rdx, %rdx
jz L(returnNULL)
movq %rsi, %rax /* Get start of delimiter set. */
/* For understanding the following code remember that %rcx == 0 now.
Although all the following instruction only modify %cl we always
have a correct zero-extended 64-bit value in %rcx. */
L(2): movb (%rax), %cl /* get byte from stopset */
testb %cl, %cl /* is NUL char? */
jz L(1) /* yes => start compare loop */
movb %cl, (%rsp,%rcx) /* set corresponding byte in stopset table */
movb 1(%rax), %cl /* get byte from stopset */
testb $0xff, %cl /* is NUL char? */
jz L(1) /* yes => start compare loop */
movb %cl, (%rsp,%rcx) /* set corresponding byte in stopset table */
movb 2(%rax), %cl /* get byte from stopset */
testb $0xff, %cl /* is NUL char? */
jz L(1) /* yes => start compare loop */
movb %cl, (%rsp,%rcx) /* set corresponding byte in stopset table */
movb 3(%rax), %cl /* get byte from stopset */
addq $4, %rax /* increment stopset pointer */
movb %cl, (%rsp,%rcx) /* set corresponding byte in stopset table */
testb $0xff, %cl /* is NUL char? */
jnz L(2) /* no => process next dword from stopset */
L(1):
leaq -4(%rdx), %rax /* 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): addq $4, %rax /* adjust pointer for full loop round */
movb (%rax), %cl /* get byte from string */
testb %cl, (%rsp,%rcx) /* is it contained in stopset? */
jz L(4) /* no => start of token */
movb 1(%rax), %cl /* get byte from string */
testb %cl, (%rsp,%rcx) /* is it contained in stopset? */
jz L(5) /* no => start of token */
movb 2(%rax), %cl /* get byte from string */
testb %cl, (%rsp,%rcx) /* is it contained in stopset? */
jz L(6) /* no => start of token */
movb 3(%rax), %cl /* get byte from string */
testb %cl, (%rsp,%rcx) /* is it contained in stopset? */
jnz L(3) /* yes => start of loop */
incq %rax /* adjust pointer */
L(6): incq %rax
L(5): incq %rax
/* Now we have to terminate the string. */
L(4): leaq -4(%rax), %rdx /* We use %rDX for the next run. */
L(7): addq $4, %rdx /* adjust pointer for full loop round */
movb (%rdx), %cl /* get byte from string */
cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */
je L(8) /* yes => return */
movb 1(%rdx), %cl /* get byte from string */
cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */
je L(9) /* yes => return */
movb 2(%rdx), %cl /* get byte from string */
cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */
je L(10) /* yes => return */
movb 3(%rdx), %cl /* get byte from string */
cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */
jne L(7) /* no => start loop again */
incq %rdx /* adjust pointer */
L(10): incq %rdx
L(9): incq %rdx
L(8): cmpq %rax, %rdx
je L(returnNULL) /* There was no token anymore. */
movb $0, (%rdx) /* Terminate string. */
/* Are we at end of string? */
cmpb $0, %cl
leaq 1(%rdx), %rcx
cmovne %rcx, %rdx
/* Store the pointer to the next character. */
mov %RDX_LP, SAVE_PTR
L(epilogue):
/* Remove the stopset table. */
addq $256, %rsp
cfi_adjust_cfa_offset(-256)
retq
L(returnNULL):
xorl %eax, %eax
/* Store the pointer to the next character. */
mov %RDX_LP, SAVE_PTR
jmp L(epilogue)
END (FUNCTION)
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