लिनक्स/linux-0.01.tar/include/string.h
< लिनक्स | linux-0.01.tar
#ifndef _STRING_H_
#define _STRING_H_
#ifndef NULL
#define NULL ((void *) 0)
#endif
#ifndef _SIZE_T
#define _SIZE_T
typedef unsigned int size_t;
#endif
extern char * strerror(int errno);
/*
* This string-include defines all string functions as inline
* functions. Use gcc. It also assumes ds=es=data space, this should be
* normal. Most of the string-functions are rather heavily hand-optimized,
* see especially strtok,strstr,str[c]spn. They should work, but are not
* very easy to understand. Everything is done entirely within the register
* set, making the functions fast and clean. String instructions have been
* used through-out, making for "slightly" unclear code :-)
*
* (C) 1991 Linus Torvalds
*/
extern inline char * strcpy(char * dest,const char *src)
{
__asm__("cld\n"
"1:\tlodsb\n\t"
"stosb\n\t"
"testb %%al,%%al\n\t"
"jne 1b"
::"S" (src),"D" (dest):"si","di","ax");
return dest;
}
extern inline char * strncpy(char * dest,const char *src,int count)
{
__asm__("cld\n"
"1:\tdecl %2\n\t"
"js 2f\n\t"
"lodsb\n\t"
"stosb\n\t"
"testb %%al,%%al\n\t"
"jne 1b\n\t"
"rep\n\t"
"stosb\n"
"2:"
::"S" (src),"D" (dest),"c" (count):"si","di","ax","cx");
return dest;
}
extern inline char * strcat(char * dest,const char * src)
{
__asm__("cld\n\t"
"repne\n\t"
"scasb\n\t"
"decl %1\n"
"1:\tlodsb\n\t"
"stosb\n\t"
"testb %%al,%%al\n\t"
"jne 1b"
::"S" (src),"D" (dest),"a" (0),"c" (0xffffffff):"si","di","ax","cx");
return dest;
}
extern inline char * strncat(char * dest,const char * src,int count)
{
__asm__("cld\n\t"
"repne\n\t"
"scasb\n\t"
"decl %1\n\t"
"movl %4,%3\n"
"1:\tdecl %3\n\t"
"js 2f\n\t"
"lodsb\n\t"
"stosb\n\t"
"testb %%al,%%al\n\t"
"jne 1b\n"
"2:\txorl %2,%2\n\t"
"stosb"
::"S" (src),"D" (dest),"a" (0),"c" (0xffffffff),"g" (count)
:"si","di","ax","cx");
return dest;
}
extern inline int strcmp(const char * cs,const char * ct)
{
register int __res __asm__("ax");
__asm__("cld\n"
"1:\tlodsb\n\t"
"scasb\n\t"
"jne 2f\n\t"
"testb %%al,%%al\n\t"
"jne 1b\n\t"
"xorl %%eax,%%eax\n\t"
"jmp 3f\n"
"2:\tmovl $1,%%eax\n\t"
"jl 3f\n\t"
"negl %%eax\n"
"3:"
:"=a" (__res):"D" (cs),"S" (ct):"si","di");
return __res;
}
extern inline int strncmp(const char * cs,const char * ct,int count)
{
register int __res __asm__("ax");
__asm__("cld\n"
"1:\tdecl %3\n\t"
"js 2f\n\t"
"lodsb\n\t"
"scasb\n\t"
"jne 3f\n\t"
"testb %%al,%%al\n\t"
"jne 1b\n"
"2:\txorl %%eax,%%eax\n\t"
"jmp 4f\n"
"3:\tmovl $1,%%eax\n\t"
"jl 4f\n\t"
"negl %%eax\n"
"4:"
:"=a" (__res):"D" (cs),"S" (ct),"c" (count):"si","di","cx");
return __res;
}
extern inline char * strchr(const char * s,char c)
{
register char * __res __asm__("ax");
__asm__("cld\n\t"
"movb %%al,%%ah\n"
"1:\tlodsb\n\t"
"cmpb %%ah,%%al\n\t"
"je 2f\n\t"
"testb %%al,%%al\n\t"
"jne 1b\n\t"
"movl $1,%1\n"
"2:\tmovl %1,%0\n\t"
"decl %0"
:"=a" (__res):"S" (s),"0" (c):"si");
return __res;
}
extern inline char * strrchr(const char * s,char c)
{
register char * __res __asm__("dx");
__asm__("cld\n\t"
"movb %%al,%%ah\n"
"1:\tlodsb\n\t"
"cmpb %%ah,%%al\n\t"
"jne 2f\n\t"
"movl %%esi,%0\n\t"
"decl %0\n"
"2:\ttestb %%al,%%al\n\t"
"jne 1b"
:"=d" (__res):"0" (0),"S" (s),"a" (c):"ax","si");
return __res;
}
extern inline int strspn(const char * cs, const char * ct)
{
register char * __res __asm__("si");
__asm__("cld\n\t"
"movl %4,%%edi\n\t"
"repne\n\t"
"scasb\n\t"
"notl %%ecx\n\t"
"decl %%ecx\n\t"
"movl %%ecx,%%edx\n"
"1:\tlodsb\n\t"
"testb %%al,%%al\n\t"
"je 2f\n\t"
"movl %4,%%edi\n\t"
"movl %%edx,%%ecx\n\t"
"repne\n\t"
"scasb\n\t"
"je 1b\n"
"2:\tdecl %0"
:"=S" (__res):"a" (0),"c" (0xffffffff),"0" (cs),"g" (ct)
:"ax","cx","dx","di");
return __res-cs;
}
extern inline int strcspn(const char * cs, const char * ct)
{
register char * __res __asm__("si");
__asm__("cld\n\t"
"movl %4,%%edi\n\t"
"repne\n\t"
"scasb\n\t"
"notl %%ecx\n\t"
"decl %%ecx\n\t"
"movl %%ecx,%%edx\n"
"1:\tlodsb\n\t"
"testb %%al,%%al\n\t"
"je 2f\n\t"
"movl %4,%%edi\n\t"
"movl %%edx,%%ecx\n\t"
"repne\n\t"
"scasb\n\t"
"jne 1b\n"
"2:\tdecl %0"
:"=S" (__res):"a" (0),"c" (0xffffffff),"0" (cs),"g" (ct)
:"ax","cx","dx","di");
return __res-cs;
}
extern inline char * strpbrk(const char * cs,const char * ct)
{
register char * __res __asm__("si");
__asm__("cld\n\t"
"movl %4,%%edi\n\t"
"repne\n\t"
"scasb\n\t"
"notl %%ecx\n\t"
"decl %%ecx\n\t"
"movl %%ecx,%%edx\n"
"1:\tlodsb\n\t"
"testb %%al,%%al\n\t"
"je 2f\n\t"
"movl %4,%%edi\n\t"
"movl %%edx,%%ecx\n\t"
"repne\n\t"
"scasb\n\t"
"jne 1b\n\t"
"decl %0\n\t"
"jmp 3f\n"
"2:\txorl %0,%0\n"
"3:"
:"=S" (__res):"a" (0),"c" (0xffffffff),"0" (cs),"g" (ct)
:"ax","cx","dx","di");
return __res;
}
extern inline char * strstr(const char * cs,const char * ct)
{
register char * __res __asm__("ax");
__asm__("cld\n\t" \
"movl %4,%%edi\n\t"
"repne\n\t"
"scasb\n\t"
"notl %%ecx\n\t"
"decl %%ecx\n\t" /* NOTE! This also sets Z if searchstring='' */
"movl %%ecx,%%edx\n"
"1:\tmovl %4,%%edi\n\t"
"movl %%esi,%%eax\n\t"
"movl %%edx,%%ecx\n\t"
"repe\n\t"
"cmpsb\n\t"
"je 2f\n\t" /* also works for empty string, see above */
"xchgl %%eax,%%esi\n\t"
"incl %%esi\n\t"
"cmpb $0,-1(%%eax)\n\t"
"jne 1b\n\t"
"xorl %%eax,%%eax\n\t"
"2:"
:"=a" (__res):"0" (0),"c" (0xffffffff),"S" (cs),"g" (ct)
:"cx","dx","di","si");
return __res;
}
extern inline int strlen(const char * s)
{
register int __res __asm__("cx");
__asm__("cld\n\t"
"repne\n\t"
"scasb\n\t"
"notl %0\n\t"
"decl %0"
:"=c" (__res):"D" (s),"a" (0),"0" (0xffffffff):"di");
return __res;
}
extern char * ___strtok;
extern inline char * strtok(char * s,const char * ct)
{
register char * __res __asm__("si");
__asm__("testl %1,%1\n\t"
"jne 1f\n\t"
"testl %0,%0\n\t"
"je 8f\n\t"
"movl %0,%1\n"
"1:\txorl %0,%0\n\t"
"movl $-1,%%ecx\n\t"
"xorl %%eax,%%eax\n\t"
"cld\n\t"
"movl %4,%%edi\n\t"
"repne\n\t"
"scasb\n\t"
"notl %%ecx\n\t"
"decl %%ecx\n\t"
"je 7f\n\t" /* empty delimeter-string */
"movl %%ecx,%%edx\n"
"2:\tlodsb\n\t"
"testb %%al,%%al\n\t"
"je 7f\n\t"
"movl %4,%%edi\n\t"
"movl %%edx,%%ecx\n\t"
"repne\n\t"
"scasb\n\t"
"je 2b\n\t"
"decl %1\n\t"
"cmpb $0,(%1)\n\t"
"je 7f\n\t"
"movl %1,%0\n"
"3:\tlodsb\n\t"
"testb %%al,%%al\n\t"
"je 5f\n\t"
"movl %4,%%edi\n\t"
"movl %%edx,%%ecx\n\t"
"repne\n\t"
"scasb\n\t"
"jne 3b\n\t"
"decl %1\n\t"
"cmpb $0,(%1)\n\t"
"je 5f\n\t"
"movb $0,(%1)\n\t"
"incl %1\n\t"
"jmp 6f\n"
"5:\txorl %1,%1\n"
"6:\tcmpb $0,(%0)\n\t"
"jne 7f\n\t"
"xorl %0,%0\n"
"7:\ttestl %0,%0\n\t"
"jne 8f\n\t"
"movl %0,%1\n"
"8:"
:"=b" (__res),"=S" (___strtok)
:"0" (___strtok),"1" (s),"g" (ct)
:"ax","cx","dx","di");
return __res;
}
extern inline void * memcpy(void * dest,const void * src, int n)
{
__asm__("cld\n\t"
"rep\n\t"
"movsb"
::"c" (n),"S" (src),"D" (dest)
:"cx","si","di");
return dest;
}
extern inline void * memmove(void * dest,const void * src, int n)
{
if (dest<src)
__asm__("cld\n\t"
"rep\n\t"
"movsb"
::"c" (n),"S" (src),"D" (dest)
:"cx","si","di");
else
__asm__("std\n\t"
"rep\n\t"
"movsb"
::"c" (n),"S" (src+n-1),"D" (dest+n-1)
:"cx","si","di");
return dest;
}
extern inline int memcmp(const void * cs,const void * ct,int count)
{
register int __res __asm__("ax");
__asm__("cld\n\t"
"repe\n\t"
"cmpsb\n\t"
"je 1f\n\t"
"movl $1,%%eax\n\t"
"jl 1f\n\t"
"negl %%eax\n"
"1:"
:"=a" (__res):"0" (0),"D" (cs),"S" (ct),"c" (count)
:"si","di","cx");
return __res;
}
extern inline void * memchr(const void * cs,char c,int count)
{
register void * __res __asm__("di");
if (!count)
return NULL;
__asm__("cld\n\t"
"repne\n\t"
"scasb\n\t"
"je 1f\n\t"
"movl $1,%0\n"
"1:\tdecl %0"
:"=D" (__res):"a" (c),"D" (cs),"c" (count)
:"cx");
return __res;
}
extern inline void * memset(void * s,char c,int count)
{
__asm__("cld\n\t"
"rep\n\t"
"stosb"
::"a" (c),"D" (s),"c" (count)
:"cx","di");
return s;
}
#endif