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Diffstat (limited to 'sysdeps/x86_64/strtok.S')
| -rw-r--r-- | sysdeps/x86_64/strtok.S | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/sysdeps/x86_64/strtok.S b/sysdeps/x86_64/strtok.S new file mode 100644 index 0000000..771bd2d --- /dev/null +++ b/sysdeps/x86_64/strtok.S @@ -0,0 +1,208 @@ +/* strtok (str, delim) -- Return next DELIM separated token from STR. + For AMD x86-64. + Copyright (C) 1998, 2000, 2001, 2002 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, 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 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 + ASM_TYPE_DIRECTIVE (save_ptr, @object) + .size save_ptr, 8 +save_ptr: + .space 8 + +# ifdef PIC +# define SAVE_PTR save_ptr(%rip) +# else +# define SAVE_PTR save_ptr +# endif + +# define FUNCTION strtok +#endif + + .text +ENTRY (BP_SYM (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. */ + movq $32, %rcx /* 32*8 bytes = 256 bytes. */ + movq %rsp, %rdi + xorq %rax, %rax /* We store 0s. */ + cld + rep + stosq + + /* Note: %rcx = 0 !!! */ + +#ifdef USE_AS_STRTOK_R + /* The value is stored in the third argument. */ + movq %rdx, %rax + movq %rdx, %r9 /* Save value - see def. of SAVE_PTR. */ + movq (%rax), %rax +#else + /* The value is in the local variable defined above. But + we have to take care for PIC code. */ + movq SAVE_PTR, %rax +#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. */ + movq %rdx, SAVE_PTR + +L(epilogue): + /* Remove the stopset table. */ + addq $256, %rsp + retq + +L(returnNULL): + xorq %rax, %rax + jmp L(epilogue) + +END (BP_SYM (FUNCTION)) |