string-486.h

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#ifndef _I386_STRING_I486_H_
#define _I386_STRING_I486_H_

/*
 * 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. 
 *
 *              Copyright (C) 1991, 1992 Linus Torvalds
 *              Revised and optimized for i486/pentium
 *              1994/03/15 by Alberto Vignani/Davide Parodi @crf.it
 *
 *      Split into 2 CPU specific files by Alan Cox to keep #ifdef noise down.
 */

#define __HAVE_ARCH_STRCPY
extern inline char * strcpy(char * dest,const char *src)
{
register char *tmp= (char *)dest;
register char dummy;
__asm__ __volatile__(
        "\n1:\t"
        "movb (%0),%2\n\t"
        "incl %0\n\t"
        "movb %2,(%1)\n\t"
        "incl %1\n\t"
        "testb %2,%2\n\t"
        "jne 1b"
        :"=r" (src), "=r" (tmp), "=q" (dummy)
        :"0" (src), "1" (tmp)
        :"memory");
return dest;
}

#define __HAVE_ARCH_STRNCPY
extern inline char * strncpy(char * dest,const char *src,size_t count)
{
register char *tmp= (char *)dest;
register char dummy;
if (count) {
__asm__ __volatile__(
        "\n1:\t"
        "movb (%0),%2\n\t"
        "incl %0\n\t"
        "movb %2,(%1)\n\t"
        "incl %1\n\t"
        "decl %3\n\t"
        "je 3f\n\t"
        "testb %2,%2\n\t"
        "jne 1b\n\t"
        "2:\tmovb %2,(%1)\n\t"
        "incl %1\n\t"
        "decl %3\n\t"
        "jne 2b\n\t"
        "3:"
        :"=r" (src), "=r" (tmp), "=q" (dummy), "=r" (count)
        :"0" (src), "1" (tmp), "3" (count)
        :"memory");
    } /* if (count) */
return dest;
}

#define __HAVE_ARCH_STRCAT
extern inline char * strcat(char * dest,const char * src)
{
register char *tmp = (char *)(dest-1);
register char dummy;
__asm__ __volatile__(
        "\n1:\tincl %1\n\t"
        "cmpb $0,(%1)\n\t"
        "jne 1b\n"
        "2:\tmovb (%2),%b0\n\t"
        "incl %2\n\t"
        "movb %b0,(%1)\n\t"
        "incl %1\n\t"
        "testb %b0,%b0\n\t"
        "jne 2b\n"
        :"=q" (dummy), "=r" (tmp), "=r" (src)
        :"1"  (tmp), "2"  (src)
        :"memory");
return dest;
}

#define __HAVE_ARCH_STRNCAT
extern inline char * strncat(char * dest,const char * src,size_t count)
{
register char *tmp = (char *)(dest-1);
register char dummy;
__asm__ __volatile__(
        "\n1:\tincl %1\n\t"
        "cmpb $0,(%1)\n\t"
        "jne 1b\n"
        "2:\tdecl %3\n\t"
        "js 3f\n\t"
        "movb (%2),%b0\n\t"
        "incl %2\n\t"
        "movb %b0,(%1)\n\t"
        "incl %1\n\t"
        "testb %b0,%b0\n\t"
        "jne 2b\n"
        "3:\txorl %0,%0\n\t"
        "movb %b0,(%1)\n\t"
        :"=q" (dummy), "=r" (tmp), "=r" (src), "=r" (count)
        :"1"  (tmp), "2"  (src), "3"  (count)
        :"memory");
return dest;
}

#define __HAVE_ARCH_STRCMP
extern inline int strcmp(const char * cs,const char * ct)
{
register int __res;
__asm__ __volatile__(
        "\n1:\tmovb (%1),%b0\n\t"
        "incl %1\n\t"
        "cmpb %b0,(%2)\n\t"
        "jne 2f\n\t"
        "incl %2\n\t"
        "testb %b0,%b0\n\t"
        "jne 1b\n\t"
        "xorl %0,%0\n\t"
        "jmp 3f\n"
        "2:\tmovl $1,%0\n\t"
        "jb 3f\n\t"
        "negl %0\n"
        "3:"
        :"=q" (__res), "=r" (cs), "=r" (ct)
        :"1" (cs), "2" (ct)
        : "memory" );
return __res;
}

#define __HAVE_ARCH_STRNCMP
extern inline int strncmp(const char * cs,const char * ct,size_t count)
{
register int __res;
__asm__ __volatile__(
        "\n1:\tdecl %3\n\t"
        "js 2f\n\t"
        "movb (%1),%b0\n\t"
        "incl %1\n\t"
        "cmpb %b0,(%2)\n\t"
        "jne 3f\n\t"
        "incl %2\n\t"
        "testb %b0,%b0\n\t"
        "jne 1b\n"
        "2:\txorl %0,%0\n\t"
        "jmp 4f\n"
        "3:\tmovl $1,%0\n\t"
        "jb 4f\n\t"
        "negl %0\n"
        "4:"
        :"=q" (__res), "=r" (cs), "=r" (ct), "=r" (count)
        :"1"  (cs), "2"  (ct),  "3" (count));
return __res;
}

#define __HAVE_ARCH_STRCHR
extern inline char * strchr(const char * s, int c)
{
register char * __res;
__asm__ __volatile__(
        "movb %%al,%%ah\n"
        "1:\tmovb (%1),%%al\n\t"
        "cmpb %%ah,%%al\n\t"
        "je 2f\n\t"
        "incl %1\n\t"
        "testb %%al,%%al\n\t"
        "jne 1b\n\t"
        "xorl %1,%1\n"
        "2:\tmovl %1,%0\n\t"
        :"=a" (__res), "=r" (s)
        :"0" (c),      "1"  (s));
return __res;
}

#define __HAVE_ARCH_STRRCHR
extern inline char * strrchr(const char * s, int c)
{
register char * __res;
__asm__ __volatile__(
        "cld\n\t"
        "movb %%al,%%ah\n"
        "1:\tlodsb\n\t"
        "cmpb %%ah,%%al\n\t"
        "jne 2f\n\t"
        "leal -1(%%esi),%0\n"
        "2:\ttestb %%al,%%al\n\t"
        "jne 1b"
        :"=d" (__res):"0" (0),"S" (s),"a" (c):"ax","si");
return __res;
}

#define __HAVE_ARCH_STRSPN
extern inline size_t strspn(const char * cs, const char * ct)
{
register char * __res;
__asm__ __volatile__(
        "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;
}

#define __HAVE_ARCH_STRCSPN
extern inline size_t strcspn(const char * cs, const char * ct)
{
register char * __res;
__asm__ __volatile__(
        "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;
}

#define __HAVE_ARCH_STRPBRK
extern inline char * strpbrk(const char * cs,const char * ct)
{
register char * __res;
__asm__ __volatile__(
        "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;
}

#define __HAVE_ARCH_STRSTR
extern inline char * strstr(const char * cs,const char * ct)
{
register char * __res;
__asm__ __volatile__(
        "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;
}

#define __HAVE_ARCH_STRLEN
extern inline size_t strlen(const char * s)
{
/*
 * slightly slower on a 486, but with better chances of
 * register allocation
 */
register char dummy, *tmp= (char *)s;
__asm__ __volatile__(
        "\n1:\t"
        "movb\t(%0),%1\n\t"
        "incl\t%0\n\t"
        "testb\t%1,%1\n\t"
        "jne\t1b"
        :"=r" (tmp),"=q" (dummy)
        :"0" (s)
        : "memory" );
return (tmp-s-1);
}

/* Added by Gertjan van Wingerde to make minix and sysv module work */
#define __HAVE_ARCH_STRNLEN
extern inline size_t strnlen(const char * s, size_t count)
{
register int __res;
__asm__ __volatile__(
        "movl %1,%0\n\t"
        "jmp 2f\n"
        "1:\tcmpb $0,(%0)\n\t"
        "je 3f\n\t"
        "incl %0\n"
        "2:\tdecl %2\n\t"
        "cmpl $-1,%2\n\t"
        "jne 1b\n"
        "3:\tsubl %1,%0"
        :"=a" (__res)
        :"c" (s),"d" (count)
        :"dx");
return __res;
}
/* end of additional stuff */

#define __HAVE_ARCH_STRTOK
extern inline char * strtok(char * s,const char * ct)
{
register char * __res;
__asm__ __volatile__(
        "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 delimiter-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","memory");
return __res;
}

#define __memcpy_c(d,s,count) \
((count%4==0) ? \
 __memcpy_by4((d),(s),(count)) : \
 ((count%2==0) ? \
  __memcpy_by2((d),(s),(count)) : \
  __memcpy_g((d),(s),(count))))

#define __HAVE_ARCH_MEMCPY
#define memcpy(d,s,count) \
(__builtin_constant_p(count) ? \
 __memcpy_c((d),(s),(count)) : \
 __memcpy_g((d),(s),(count)))

/*
 *      These ought to get tweaked to do some cache priming.
 */
 
extern inline void * __memcpy_by4(void * to, const void * from, size_t n)
{
register void *tmp = (void *)to;
register int dummy1,dummy2;
__asm__ __volatile__ (
        "\n1:\tmovl (%2),%0\n\t"
        "addl $4,%2\n\t"
        "movl %0,(%1)\n\t"
        "addl $4,%1\n\t"
        "decl %3\n\t"
        "jnz 1b"
        :"=r" (dummy1), "=r" (tmp), "=r" (from), "=r" (dummy2) 
        :"1" (tmp), "2" (from), "3" (n/4)
        :"memory");
return (to);
}

extern inline void * __memcpy_by2(void * to, const void * from, size_t n)
{
register void *tmp = (void *)to;
register int dummy1,dummy2;
__asm__ __volatile__ (
        "shrl $1,%3\n\t"
        "jz 2f\n"                 /* only a word */
        "1:\tmovl (%2),%0\n\t"
        "addl $4,%2\n\t"
        "movl %0,(%1)\n\t"
        "addl $4,%1\n\t"
        "decl %3\n\t"
        "jnz 1b\n"
        "2:\tmovw (%2),%w0\n\t"
        "movw %w0,(%1)"
        :"=r" (dummy1), "=r" (tmp), "=r" (from), "=r" (dummy2) 
        :"1" (tmp), "2" (from), "3" (n/2)
        :"memory");
return (to);
}

extern inline void * __memcpy_g(void * to, const void * from, size_t n)
{
register void *tmp = (void *)to;
__asm__ __volatile__ (
        "cld\n\t"
        "shrl $1,%%ecx\n\t"
        "jnc 1f\n\t"
        "movsb\n"
        "1:\tshrl $1,%%ecx\n\t"
        "jnc 2f\n\t"
        "movsw\n"
        "2:\trep\n\t"
        "movsl"
        : /* no output */
        :"c" (n),"D" ((long) tmp),"S" ((long) from)
        :"cx","di","si","memory");
return (to);
}


#define __HAVE_ARCH_MEMMOVE
extern inline void * memmove(void * dest,const void * src, size_t n)
{
register void *tmp = (void *)dest;
if (dest<src)
__asm__ __volatile__ (
        "cld\n\t"
        "rep\n\t"
        "movsb"
        : /* no output */
        :"c" (n),"S" (src),"D" (tmp)
        :"cx","si","di");
else
__asm__ __volatile__ (
        "std\n\t"
        "rep\n\t"
        "movsb\n\t"
        "cld"
        : /* no output */
        :"c" (n), "S" (n-1+(const char *)src), "D" (n-1+(char *)tmp)
        :"cx","si","di","memory");
return dest;
}

extern inline int memcmp(const void * cs,const void * ct,size_t count)
{
register int __res;
__asm__ __volatile__(
        "cld\n\t"
        "repe\n\t"
        "cmpsb\n\t"
        "je 1f\n\t"
        "sbbl %0,%0\n\t"
        "orb $1,%b0\n"
        "1:"
        :"=abd" (__res):"0" (0),"S" (cs),"D" (ct),"c" (count)
        :"si","di","cx");
return __res;
}

#define __HAVE_ARCH_MEMCHR
extern inline void * memchr(const void * cs,int c,size_t count)
{
register void * __res;
if (!count)
        return NULL;
__asm__ __volatile__(
        "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;
}

#define __memset_cc(s,c,count) \
((count%4==0) ? \
 __memset_cc_by4((s),(c),(count)) : \
 ((count%2==0) ? \
  __memset_cc_by2((s),(c),(count)) : \
  __memset_cg((s),(c),(count))))

#define __memset_gc(s,c,count) \
((count%4==0) ? \
 __memset_gc_by4((s),(c),(count)) : \
 ((count%2==0) ? \
  __memset_gc_by2((s),(c),(count)) : \
  __memset_gg((s),(c),(count))))

#define __HAVE_ARCH_MEMSET
#define memset(s,c,count) \
(__builtin_constant_p(c) ? \
 (__builtin_constant_p(count) ? \
  __memset_cc((s),(c),(count)) : \
  __memset_cg((s),(c),(count))) : \
 (__builtin_constant_p(count) ? \
  __memset_gc((s),(c),(count)) : \
  __memset_gg((s),(c),(count))))

extern inline void * __memset_cc_by4(void * s, char c, size_t count)
{
/*
 * register char *tmp = s;
 */
register char *tmp = (char *)s;
register int  dummy;
__asm__ __volatile__ (
        "\n1:\tmovl %2,(%0)\n\t"
        "addl $4,%0\n\t"
        "decl %1\n\t"
        "jnz 1b"
        :"=r" (tmp), "=r" (dummy)
        :"q" (0x01010101UL * (unsigned char) c), "0" (tmp), "1" (count/4)
        :"memory");
return s;
}

extern inline void * __memset_cc_by2(void * s, char c, size_t count)
{
register void *tmp = (void *)s;
register int  dummy;
__asm__ __volatile__ (
        "shrl $1,%1\n\t"          /* may be divisible also by 4 */
        "jz 2f\n"
        "\n1:\tmovl %2,(%0)\n\t"
        "addl $4,%0\n\t"
        "decl %1\n\t"
        "jnz 1b\n"
        "2:\tmovw %w2,(%0)"
        :"=r" (tmp), "=r" (dummy)
        :"q" (0x01010101UL * (unsigned char) c), "0" (tmp), "1" (count/2)
        :"memory");
return s;
}

extern inline void * __memset_gc_by4(void * s, char c, size_t count)
{
register void *tmp = (void *)s;
register int dummy;
__asm__ __volatile__ (
        "movb %b0,%h0\n"
        "pushw %w0\n\t"
        "shll $16,%0\n\t"
        "popw %w0\n"
        "1:\tmovl %0,(%1)\n\t"
        "addl $4,%1\n\t"
        "decl %2\n\t"
        "jnz 1b\n"
        :"=q" (c), "=r" (tmp), "=r" (dummy)
        :"0" ((unsigned) c),  "1"  (tmp), "2" (count/4)
        :"memory");
return s;
}

extern inline void * __memset_gc_by2(void * s, char c, size_t count)
{
register void *tmp = (void *)s;
register int dummy1,dummy2;
__asm__ __volatile__ (
        "movb %b0,%h0\n\t"
        "shrl $1,%2\n\t"          /* may be divisible also by 4 */
        "jz 2f\n\t"
        "pushw %w0\n\t"
        "shll $16,%0\n\t"
        "popw %w0\n"
        "1:\tmovl %0,(%1)\n\t"
        "addl $4,%1\n\t"
        "decl %2\n\t"
        "jnz 1b\n"
        "2:\tmovw %w0,(%1)"
        :"=q" (dummy1), "=r" (tmp), "=r" (dummy2)
        :"0" ((unsigned) c),  "1"  (tmp), "2" (count/2)
        :"memory");
return s;
}

extern inline void * __memset_cg(void * s, char c, size_t count)
{
register void *tmp = (void *)s;
__asm__ __volatile__ (
        "shrl $1,%%ecx\n\t"
        "rep\n\t"
        "stosw\n\t"
        "jnc 1f\n\t"
        "movb %%al,(%%edi)\n"
        "1:"
        : /* no output */
        :"c" (count),"D" (tmp), "a" (0x0101U * (unsigned char) c)
        :"cx","di","memory");
return s;
}

extern inline void * __memset_gg(void * s,char c,size_t count)
{
register void *tmp = (void *)s;
__asm__ __volatile__ (
        "movb %%al,%%ah\n\t"
        "shrl $1,%%ecx\n\t"
        "rep\n\t"
        "stosw\n\t"
        "jnc 1f\n\t"
        "movb %%al,(%%edi)\n"
        "1:"
        : /* no output */
        :"c" (count),"D" (tmp), "a" (c)
        :"cx","di","memory");
return s;
}


/*
 * find the first occurrence of byte 'c', or 1 past the area if none
 */
#define __HAVE_ARCH_MEMSCAN
extern inline void * memscan(void * addr, int c, size_t size)
{
        if (!size)
                return addr;
        __asm__("cld
                repnz; scasb
                jnz 1f
                dec %%edi
1:              "
                : "=D" (addr), "=c" (size)
                : "0" (addr), "1" (size), "a" (c));
        return addr;
}

#endif

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