diff options
Diffstat (limited to 'sysdeps/i386')
| -rw-r--r-- | sysdeps/i386/bits/string.h | 60 | ||||
| -rw-r--r-- | sysdeps/i386/i486/bits/string.h | 60 | ||||
| -rw-r--r-- | sysdeps/i386/stackinfo.h | 28 | ||||
| -rw-r--r-- | sysdeps/i386/strchrnul.S | 275 |
4 files changed, 423 insertions, 0 deletions
diff --git a/sysdeps/i386/bits/string.h b/sysdeps/i386/bits/string.h index 4bd65af7f1..5a67c1b4e1 100644 --- a/sysdeps/i386/bits/string.h +++ b/sysdeps/i386/bits/string.h @@ -517,6 +517,66 @@ __strchr_c (__const char *__s, int __c) } +/* Find the first occurrence of C in S or the final NUL byte. */ +#define _HAVE_STRING_ARCH_strchrnul 1 +#define __strchrnul(s, c) \ + (__extension__ (__builtin_constant_p (c) \ + ? ((c) == '\0' \ + ? (char *) __rawmemchr (s, c) \ + : __strchrnul_c (s, ((c) & 0xff) << 8)) \ + : __strchrnul_g (s, c))) + +__STRING_INLINE char *__strchrnul_g (__const char *__s, int __c); + +__STRING_INLINE char * +__strchrnul_g (__const char *__s, int __c) +{ + register unsigned long int __d0; + register char *__res; + __asm__ __volatile__ + ("cld\n\t" + "movb %%al,%%ah\n" + "1:\n\t" + "lodsb\n\t" + "cmpb %%ah,%%al\n\t" + "je 2f\n\t" + "testb %%al,%%al\n\t" + "jne 1b\n\t" + "2:\n\t" + "movl %1,%0" + : "=a" (__res), "=&S" (__d0) + : "0" (__c), "1" (__s) + : "cc"); + return __res - 1; +} + +__STRING_INLINE char *__strchrnul_c (__const char *__s, int __c); + +__STRING_INLINE char * +__strchrnul_c (__const char *__s, int __c) +{ + register unsigned long int __d0; + register char *__res; + __asm__ __volatile__ + ("cld\n\t" + "1:\n\t" + "lodsb\n\t" + "cmpb %%ah,%%al\n\t" + "je 2f\n\t" + "testb %%al,%%al\n\t" + "jne 1b\n\t" + "2:\n\t" + "movl %1,%0" + : "=a" (__res), "=&S" (__d0) + : "0" (__c), "1" (__s) + : "cc"); + return __res - 1; +} +#ifdef __USE_GNU +# define strchrnul(s, c) __strchrnul (s, c) +#endif + + /* Return the length of the initial segment of S which consists entirely of characters not in REJECT. */ #define _HAVE_STRING_ARCH_strcspn 1 diff --git a/sysdeps/i386/i486/bits/string.h b/sysdeps/i386/i486/bits/string.h index 6e5c3fed1f..cb0229b5cd 100644 --- a/sysdeps/i386/i486/bits/string.h +++ b/sysdeps/i386/i486/bits/string.h @@ -1056,6 +1056,66 @@ __strchr_g (__const char *__s, int __c) } +/* Find the first occurrence of C in S or the final NUL byte. */ +#define _HAVE_STRING_ARCH_strchrnul 1 +#define __strchrnul(s, c) \ + (__extension__ (__builtin_constant_p (c) \ + ? ((c) == '\0' \ + ? (char *) __rawmemchr (s, c) \ + : __strchrnul_c (s, ((c) & 0xff) << 8)) \ + : __strchrnul_g (s, c))) + +__STRING_INLINE char *__strchrnul_c (__const char *__s, int __c); + +__STRING_INLINE char * +__strchrnul_c (__const char *__s, int __c) +{ + register unsigned long int __d0; + register char *__res; + __asm__ __volatile__ + ("1:\n\t" + "movb (%0),%%al\n\t" + "cmpb %%ah,%%al\n\t" + "je 2f\n\t" + "leal 1(%0),%0\n\t" + "testb %%al,%%al\n\t" + "jne 1b\n\t" + "decl %0\n" + "2:" + : "=r" (__res), "=&a" (__d0) + : "0" (__s), "1" (__c) + : "cc"); + return __res; +} + +__STRING_INLINE char *__strchrnul_g (__const char *__s, int __c); + +__STRING_INLINE char * +__strchrnul_g (__const char *__s, int __c) +{ + register unsigned long int __d0; + register char *__res; + __asm__ __volatile__ + ("movb %%al,%%ah\n" + "1:\n\t" + "movb (%0),%%al\n\t" + "cmpb %%ah,%%al\n\t" + "je 2f\n\t" + "leal 1(%0),%0\n\t" + "testb %%al,%%al\n\t" + "jne 1b\n\t" + "decl %0\n" + "2:" + : "=r" (__res), "=&a" (__d0) + : "0" (__s), "1" (__c) + : "cc"); + return __res; +} +#ifdef __USE_GNU +# define strchrnul(s, c) __strchrnul (s, c) +#endif + + #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED /* Find the first occurrence of C in S. This is the BSD name. */ # define _HAVE_STRING_ARCH_index 1 diff --git a/sysdeps/i386/stackinfo.h b/sysdeps/i386/stackinfo.h new file mode 100644 index 0000000000..2fe865a364 --- /dev/null +++ b/sysdeps/i386/stackinfo.h @@ -0,0 +1,28 @@ +/* Copyright (C) 1999 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +/* This file contains a bit of information about the stack allocation + of the processor. */ + +#ifndef _STACKINFO_H +#define _STACKINFO_H 1 + +/* On x86 the stack grows down. */ +#define _STACK_GROWS_DOWN 1 + +#endif /* stackinfo.h */ diff --git a/sysdeps/i386/strchrnul.S b/sysdeps/i386/strchrnul.S new file mode 100644 index 0000000000..45950c3564 --- /dev/null +++ b/sysdeps/i386/strchrnul.S @@ -0,0 +1,275 @@ +/* strchrnul (str, ch) -- Return pointer to first occurrence of CH in STR + or the final NUL byte. + For Intel 80x86, x>=3. + Copyright (C) 1994, 1995, 1996, 1997, 1999 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@gnu.org> + Some optimisations by Alan Modra <Alan@SPRI.Levels.UniSA.Edu.Au> + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. 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" + +/* + INPUT PARAMETERS: + str (sp + 4) + ch (sp + 8) +*/ + + .text +ENTRY (__strchrnul) + pushl %edi /* Save callee-safe registers used here. */ + + movl 8(%esp), %eax /* get string pointer */ + movl 12(%esp), %edx /* get character we are looking for */ + + /* At the moment %edx contains C. What we need for the + algorithm is C in all bytes of the dword. Avoid + operations on 16 bit words because these require an + prefix byte (and one more cycle). */ + movb %dl, %dh /* now it is 0|0|c|c */ + movl %edx, %ecx + shll $16, %edx /* now it is c|c|0|0 */ + movw %cx, %dx /* and finally c|c|c|c */ + + /* Before we start with the main loop we process single bytes + until the source pointer is aligned. This has two reasons: + 1. aligned 32-bit memory access is faster + and (more important) + 2. we process in the main loop 32 bit in one step although + we don't know the end of the string. But accessing at + 4-byte alignment guarantees that we never access illegal + memory if this would not also be done by the trivial + implementation (this is because all processor inherent + boundaries are multiples of 4. */ + + testb $3, %eax /* correctly aligned ? */ + jz L(11) /* yes => begin loop */ + movb (%eax), %cl /* load byte in question (we need it twice) */ + cmpb %cl, %dl /* compare byte */ + je L(6) /* target found => return */ + testb %cl, %cl /* is NUL? */ + jz L(6) /* yes => return NULL */ + incl %eax /* increment pointer */ + + testb $3, %eax /* correctly aligned ? */ + jz L(11) /* yes => begin loop */ + movb (%eax), %cl /* load byte in question (we need it twice) */ + cmpb %cl, %dl /* compare byte */ + je L(6) /* target found => return */ + testb %cl, %cl /* is NUL? */ + jz L(6) /* yes => return NULL */ + incl %eax /* increment pointer */ + + testb $3, %eax /* correctly aligned ? */ + jz L(11) /* yes => begin loop */ + movb (%eax), %cl /* load byte in question (we need it twice) */ + cmpb %cl, %dl /* compare byte */ + je L(6) /* target found => return */ + testb %cl, %cl /* is NUL? */ + jz L(6) /* yes => return NULL */ + incl %eax /* increment pointer */ + + /* No we have reached alignment. */ + jmp L(11) /* begin loop */ + + /* We exit the loop if adding MAGIC_BITS to LONGWORD fails to + change any of the hole bits of LONGWORD. + + 1) Is this safe? Will it catch all the zero bytes? + Suppose there is a byte with all zeros. Any carry bits + propagating from its left will fall into the hole at its + least significant bit and stop. Since there will be no + carry from its most significant bit, the LSB of the + byte to the left will be unchanged, and the zero will be + detected. + + 2) Is this worthwhile? Will it ignore everything except + zero bytes? Suppose every byte of LONGWORD has a bit set + somewhere. There will be a carry into bit 8. If bit 8 + is set, this will carry into bit 16. If bit 8 is clear, + one of bits 9-15 must be set, so there will be a carry + into bit 16. Similarly, there will be a carry into bit + 24. If one of bits 24-31 is set, there will be a carry + into bit 32 (=carry flag), so all of the hole bits will + be changed. + + 3) But wait! Aren't we looking for C, not zero? + Good point. So what we do is XOR LONGWORD with a longword, + each of whose bytes is C. This turns each byte that is C + into a zero. */ + + /* Each round the main loop processes 16 bytes. */ + + ALIGN(4) + +L(1): addl $16, %eax /* adjust pointer for whole round */ + +L(11): movl (%eax), %ecx /* get word (= 4 bytes) in question */ + xorl %edx, %ecx /* XOR with word c|c|c|c => bytes of str == c + are now 0 */ + movl $0xfefefeff, %edi /* magic value */ + addl %ecx, %edi /* add the magic value to the word. We get + carry bits reported for each byte which + is *not* C */ + + /* According to the algorithm we had to reverse the effect of the + XOR first and then test the overflow bits. But because the + following XOR would destroy the carry flag and it would (in a + representation with more than 32 bits) not alter then last + overflow, we can now test this condition. If no carry is signaled + no overflow must have occurred in the last byte => it was 0. */ + jnc L(7) + + /* We are only interested in carry bits that change due to the + previous add, so remove original bits */ + xorl %ecx, %edi /* ((word^charmask)+magic)^(word^charmask) */ + + /* Now test for the other three overflow bits. */ + orl $0xfefefeff, %edi /* set all non-carry bits */ + incl %edi /* add 1: if one carry bit was *not* set + the addition will not result in 0. */ + + /* If at least one byte of the word is C we don't get 0 in %edi. */ + jnz L(7) /* found it => return pointer */ + + /* Now we made sure the dword does not contain the character we are + looking for. But because we deal with strings we have to check + for the end of string before testing the next dword. */ + + xorl %edx, %ecx /* restore original dword without reload */ + movl $0xfefefeff, %edi /* magic value */ + addl %ecx, %edi /* add the magic value to the word. We get + carry bits reported for each byte which + is *not* 0 */ + jnc L(71) /* highest byte is NUL => return NULL */ + xorl %ecx, %edi /* (word+magic)^word */ + orl $0xfefefeff, %edi /* set all non-carry bits */ + incl %edi /* add 1: if one carry bit was *not* set + the addition will not result in 0. */ + jnz L(71) /* found NUL => return NULL */ + + movl 4(%eax), %ecx /* get word (= 4 bytes) in question */ + xorl %edx, %ecx /* XOR with word c|c|c|c => bytes of str == c + are now 0 */ + movl $0xfefefeff, %edi /* magic value */ + addl %ecx, %edi /* add the magic value to the word. We get + carry bits reported for each byte which + is *not* C */ + jnc L(71) /* highest byte is C => return pointer */ + xorl %ecx, %edi /* ((word^charmask)+magic)^(word^charmask) */ + orl $0xfefefeff, %edi /* set all non-carry bits */ + incl %edi /* add 1: if one carry bit was *not* set + the addition will not result in 0. */ + jnz L(71) /* found it => return pointer */ + xorl %edx, %ecx /* restore original dword without reload */ + movl $0xfefefeff, %edi /* magic value */ + addl %ecx, %edi /* add the magic value to the word. We get + carry bits reported for each byte which + is *not* 0 */ + jnc L(71) /* highest byte is NUL => return NULL */ + xorl %ecx, %edi /* (word+magic)^word */ + orl $0xfefefeff, %edi /* set all non-carry bits */ + incl %edi /* add 1: if one carry bit was *not* set + the addition will not result in 0. */ + jnz L(71) /* found NUL => return NULL */ + + movl 8(%eax), %ecx /* get word (= 4 bytes) in question */ + xorl %edx, %ecx /* XOR with word c|c|c|c => bytes of str == c + are now 0 */ + movl $0xfefefeff, %edi /* magic value */ + addl %ecx, %edi /* add the magic value to the word. We get + carry bits reported for each byte which + is *not* C */ + jnc L(72) /* highest byte is C => return pointer */ + xorl %ecx, %edi /* ((word^charmask)+magic)^(word^charmask) */ + orl $0xfefefeff, %edi /* set all non-carry bits */ + incl %edi /* add 1: if one carry bit was *not* set + the addition will not result in 0. */ + jnz L(72) /* found it => return pointer */ + xorl %edx, %ecx /* restore original dword without reload */ + movl $0xfefefeff, %edi /* magic value */ + addl %ecx, %edi /* add the magic value to the word. We get + carry bits reported for each byte which + is *not* 0 */ + jnc L(72) /* highest byte is NUL => return NULL */ + xorl %ecx, %edi /* (word+magic)^word */ + orl $0xfefefeff, %edi /* set all non-carry bits */ + incl %edi /* add 1: if one carry bit was *not* set + the addition will not result in 0. */ + jnz L(72) /* found NUL => return NULL */ + + movl 12(%eax), %ecx /* get word (= 4 bytes) in question */ + xorl %edx, %ecx /* XOR with word c|c|c|c => bytes of str == c + are now 0 */ + movl $0xfefefeff, %edi /* magic value */ + addl %ecx, %edi /* add the magic value to the word. We get + carry bits reported for each byte which + is *not* C */ + jnc L(73) /* highest byte is C => return pointer */ + xorl %ecx, %edi /* ((word^charmask)+magic)^(word^charmask) */ + orl $0xfefefeff, %edi /* set all non-carry bits */ + incl %edi /* add 1: if one carry bit was *not* set + the addition will not result in 0. */ + jnz L(73) /* found it => return pointer */ + xorl %edx, %ecx /* restore original dword without reload */ + movl $0xfefefeff, %edi /* magic value */ + addl %ecx, %edi /* add the magic value to the word. We get + carry bits reported for each byte which + is *not* 0 */ + jnc L(73) /* highest byte is NUL => return NULL */ + xorl %ecx, %edi /* (word+magic)^word */ + orl $0xfefefeff, %edi /* set all non-carry bits */ + incl %edi /* add 1: if one carry bit was *not* set + the addition will not result in 0. */ + jz L(1) /* no NUL found => restart loop */ + +L(73): addl $4, %eax /* adjust pointer */ +L(72): addl $4, %eax +L(71): addl $4, %eax + + /* We now scan for the byte in which the character was matched. + But we have to take care of the case that a NUL char is + found before this in the dword. */ + +L(7): testb %cl, %cl /* is first byte C? */ + jz L(6) /* yes => return pointer */ + cmpb %dl, %cl /* is first byte NUL? */ + je L(6) /* yes => return NULL */ + incl %eax /* it's not in the first byte */ + + testb %ch, %ch /* is second byte C? */ + jz L(6) /* yes => return pointer */ + cmpb %dl, %ch /* is second byte NUL? */ + je L(6) /* yes => return NULL? */ + incl %eax /* it's not in the second byte */ + + shrl $16, %ecx /* make upper byte accessible */ + testb %cl, %cl /* is third byte C? */ + jz L(6) /* yes => return pointer */ + cmpb %dl, %cl /* is third byte NUL? */ + je L(6) /* yes => return NULL */ + + /* It must be in the fourth byte and it cannot be NUL. */ + incl %eax + +L(6): popl %edi /* restore saved register content */ + + ret +END (__strchrnul) + +weak_alias (__strchrnul, strchrnul) |