/* strtok (str, delim) -- Return next DELIM separated token from STR. For AMD x86-64. Copyright (C) 1998-2016 Free Software Foundation, Inc. This file is part of the GNU C Library. Based on i686 version contributed by Ulrich Drepper , 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 . */ #include #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)