string.h

一个微型操作系统源码

/*
 * OSV
 * Copyright (C) 2002 Ciprian DOSOFTEI <[e-mail]>
 * All rights reserved.
 * 
 * http://backster.free.fr/osv
 *
 * This file is part of the OSV project. OSV is free software, also known as
 * "open source"; you can redistribute it and/or modify it under the terms 
 * of the GNU General Public License (GPL), version 2, as published by the Free
 * Software Foundation (FSF). To explore alternate licensing terms, contact 
 * the author at [e-mail] or [phone].
 * 
 * OSV 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 GPL for more details.  You should have
 * received a copy of the GPL along with OSV; see the file COPYING.  If
 * not, write to the FSF, 59 Temple Place #330, Boston, MA 02111-1307, USA.
 */

#ifndef INCSTRING
#define INCSTRING

#include <types.h>

#define __HAVE_ARCH_STRCPY
extern inline char * strcpy(char * dest, const char *src) {
    int d0, d1, d2;
    
    __asm__ __volatile__(
	"cld\n"
	"1:\tlodsb\n\t"
	"stosb\n\t"
	"testb %%al,%%al\n\t"
	"jne 1b"
	: "=&S" (d0), "=&D" (d1), "=&a" (d2)
	:"0" (src),"1" (dest) : "memory");
    return dest;
}

#define __HAVE_ARCH_STRNCPY
extern inline char * strncpy(char * dest, const char *src, size_t count) {
    int d0, d1, d2, d3;
    
    __asm__ __volatile__(
	"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" (d0), "=&D" (d1), "=&c" (d2), "=&a" (d3)
	:"0" (src),"1" (dest),"2" (count) : "memory");
    return dest;
}

#define __HAVE_ARCH_STRCAT
extern inline char * strcat(char * dest, const char * src) {
    int d0, d1, d2, d3;
    
    __asm__ __volatile__(
	"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" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3)
	: "0" (src), "1" (dest), "2" (0), "3" (0xffffffff):"memory");
    return dest;
}

#define __HAVE_ARCH_STRNCAT
extern inline char * strncat(char * dest, const char * src, size_t count) {
    int d0, d1, d2, d3;
    
    __asm__ __volatile__(
	"cld\n\t"
	"repne\n\t"
	"scasb\n\t"
	"decl %1\n\t"
	"movl %8,%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" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3)
	: "0" (src),"1" (dest),"2" (0),"3" (0xffffffff), "g" (count)
	: "memory");
    return dest;
}

#define __HAVE_ARCH_STRCMP
extern inline int strcmp(const char * cs, const char * ct) {
    int d0, d1;
    register int __res;
    
    __asm__ __volatile__(
	"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:\tsbbl %%eax,%%eax\n\t"
	"orb $1,%%al\n"
	"3:"
	:"=a" (__res), "=&S" (d0), "=&D" (d1)
		     :"1" (cs),"2" (ct));
    return __res;
}

#define __HAVE_ARCH_STRNCMP
extern inline int strncmp(const char * cs, const char * ct, size_t count) {
    register int __res;
    int d0, d1, d2;
    
    __asm__ __volatile__(
	"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:\tsbbl %%eax,%%eax\n\t"
	"orb $1,%%al\n"
	"4:"
		     :"=a" (__res), "=&S" (d0), "=&D" (d1), "=&c" (d2)
		     :"1" (cs),"2" (ct),"3" (count));
    return __res;
}

#define __HAVE_ARCH_STRCHR
extern inline char * strchr(const char * s, int c) {
    int d0;
    register char * __res;
    
    __asm__ __volatile__(
	"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" (d0) : "1" (s),"0" (c));
    return __res;
}

#define __HAVE_ARCH_STRRCHR
extern inline char * strrchr(const char * s, int c) {
    int d0, d1;
    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"
	:"=g" (__res), "=&S" (d0), "=&a" (d1) :"0" (0),"1" (s),"2" (c));
    return __res;
}

#define __HAVE_ARCH_STRLEN
extern inline size_t strlen(const char * s) {
    int d0;
    register int __res;
    
    __asm__ __volatile__(
	"cld\n\t"
	"repne\n\t"
	"scasb\n\t"
	"notl %0\n\t"
	"decl %0"
	:"=c" (__res), "=&D" (d0) :"1" (s),"a" (0), "0" (0xffffffff));
    return __res;
}

extern inline void * __memcpy(void * to, const void * from, size_t n) {
    int d0, d1, d2;
    
    __asm__ __volatile__(
	"cld\n\t"
	"rep ; movsl\n\t"
	"testb $2,%b4\n\t"
	"je 1f\n\t"
	"movsw\n"
	"1:\ttestb $1,%b4\n\t"
	"je 2f\n\t"
	"movsb\n"
	"2:"
	: "=&c" (d0), "=&D" (d1), "=&S" (d2)
	:"0" (n/4), "q" (n),"1" ((long) to),"2" ((long) from)
	: "memory");
    return (to);
}

extern inline void * __constant_memcpy(void * to, const void * from, size_t n)
{
	switch (n) {
		case 0:
			return to;
		case 1:
			*(unsigned char *)to = *(const unsigned char *)from;
			return to;
		case 2:
			*(unsigned short *)to = *(const unsigned short *)from;
			return to;
		case 3:
			*(unsigned short *)to = *(const unsigned short *)from;
			*(2+(unsigned char *)to) = *(2+(const unsigned char *)from);
			return to;
		case 4:
			*(unsigned long *)to = *(const unsigned long *)from;
			return to;
		case 6:	/* for Ethernet addresses */
			*(unsigned long *)to = *(const unsigned long *)from;
			*(2+(unsigned short *)to) = *(2+(const unsigned short *)from);
			return to;
		case 8:
			*(unsigned long *)to = *(const unsigned long *)from;
			*(1+(unsigned long *)to) = *(1+(const unsigned long *)from);
			return to;
		case 12:
			*(unsigned long *)to = *(const unsigned long *)from;
			*(1+(unsigned long *)to) = *(1+(const unsigned long *)from);
			*(2+(unsigned long *)to) = *(2+(const unsigned long *)from);
			return to;
		case 16:
			*(unsigned long *)to = *(const unsigned long *)from;
			*(1+(unsigned long *)to) = *(1+(const unsigned long *)from);
			*(2+(unsigned long *)to) = *(2+(const unsigned long *)from);
			*(3+(unsigned long *)to) = *(3+(const unsigned long *)from);
			return to;
		case 20:
			*(unsigned long *)to = *(const unsigned long *)from;
			*(1+(unsigned long *)to) = *(1+(const unsigned long *)from);
			*(2+(unsigned long *)to) = *(2+(const unsigned long *)from);
			*(3+(unsigned long *)to) = *(3+(const unsigned long *)from);
			*(4+(unsigned long *)to) = *(4+(const unsigned long *)from);
			return to;
	}
#define COMMON(x) \
__asm__ __volatile__( \
	"cld\n\t" \
	"rep ; movsl" \
	x \
	: "=&c" (d0), "=&D" (d1), "=&S" (d2) \
	: "0" (n/4),"1" ((long) to),"2" ((long) from) \
	: "memory");
{
	int d0, d1, d2;
	switch (n % 4) {
		case 0: COMMON(""); return to;
		case 1: COMMON("\n\tmovsb"); return to;
		case 2: COMMON("\n\tmovsw"); return to;
		default: COMMON("\n\tmovsw\n\tmovsb"); return to;
	}
}

#undef COMMON
}

#define __HAVE_ARCH_MEMCPY
#define memcpy(t, f, n) \
(__builtin_constant_p(n) ? \
 __constant_memcpy((t),(f),(n)) : \
 __memcpy((t),(f),(n)))

#define __HAVE_ARCH_MEMMOVE
extern inline void * memmove(void * dest, const void * src, size_t n) {
    int d0, d1, d2;
    
    if (dest<src)
    __asm__ __volatile__(
	"cld\n\t"
	"rep\n\t"
	"movsb"
	: "=&c" (d0), "=&S" (d1), "=&D" (d2)
	:"0" (n),"1" (src),"2" (dest)
	: "memory");
    else
    __asm__ __volatile__(
	"std\n\t"
	"rep\n\t"
	"movsb\n\t"
	"cld"
	: "=&c" (d0), "=&S" (d1), "=&D" (d2)
	:"0" (n),
	 "1" (n-1+(const char *)src),
	 "2" (n-1+(char *)dest)
	:"memory");
    return dest;
}

#define memcmp __builtin_memcmp

#define __HAVE_ARCH_MEMCHR
extern inline void * memchr(const void * cs, int c, size_t count) {
    int d0;
    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), "=&c" (d0) : "a" (c),"0" (cs),"1" (count));
    return __res;
}

extern inline void * __memset_generic(void * s, char c, size_t count) {
    int d0, d1;
    
    __asm__ __volatile__(
	"cld\n\t"
	"rep\n\t"
	"stosb"
	: "=&c" (d0), "=&D" (d1)
	:"a" (c),"1" (s),"0" (count)
	:"memory");
    return s;
}

/* we might want to write optimized versions of these later */
#define __constant_count_memset(s,c,count) __memset_generic((s),(c),(count))

/*
 * memset(x,0,y) is a reasonably common thing to do, so we want to fill
 * things 32 bits at a time even when we don't know the size of the
 * area at compile-time..
 */
extern inline void * __constant_c_memset(void * s, unsigned long c, size_t count) {
    int d0, d1;
    
    __asm__ __volatile__(
	"cld\n\t"
	"rep ; stosl\n\t"
	"testb $2,%b3\n\t"
	"je 1f\n\t"
	"stosw\n"
	"1:\ttestb $1,%b3\n\t"
	"je 2f\n\t"
	"stosb\n"
	"2:"
	: "=&c" (d0), "=&D" (d1)
	:"a" (c), "q" (count), "0" (count/4), "1" ((long) s)
	:"memory");
    return (s);
}

/* 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) {
    int d0;
    register int __res;
    
    __asm__ __volatile__(
	"movl %2,%0\n\t"
	"jmp 2f\n"
	"1:\tcmpb $0,(%0)\n\t"
	"je 3f\n\t"
	"incl %0\n"
	"2:\tdecl %1\n\t"
	"cmpl $-1,%1\n\t"
	"jne 1b\n"
	"3:\tsubl %2,%0"
	:"=a" (__res), "=&d" (d0)
	:"c" (s),"1" (count));
    return __res;
}
/* end of additional stuff */

extern inline void * __constant_c_and_count_memset(void * s, unsigned long pattern, size_t count) {
	switch (count) {
		case 0:
			return s;
		case 1:
			*(unsigned char *)s = pattern;
			return s;
		case 2:
			*(unsigned short *)s = pattern;
			return s;
		case 3:
			*(unsigned short *)s = pattern;
			*(2+(unsigned char *)s) = pattern;
			return s;
		case 4:
			*(unsigned long *)s = pattern;
			return s;
	}
#define COMMON(x) \
__asm__  __volatile__("cld\n\t" \
	"rep ; stosl" \
	x \
	: "=&c" (d0), "=&D" (d1) \
	: "a" (pattern),"0" (count/4),"1" ((long) s) \
	: "memory")
{
	int d0, d1;
	switch (count % 4) {
		case 0: COMMON(""); return s;
		case 1: COMMON("\n\tstosb"); return s;
		case 2: COMMON("\n\tstosw"); return s;
		default: COMMON("\n\tstosw\n\tstosb"); return s;
	}
}

#undef COMMON
}

#define __constant_c_x_memset(s, c, count) \
(__builtin_constant_p(count) ? \
 __constant_c_and_count_memset((s),(c),(count)) : \
 __constant_c_memset((s),(c),(count)))

#define __memset(s, c, count) \
(__builtin_constant_p(count) ? \
 __constant_count_memset((s),(c),(count)) : \
 __memset_generic((s),(c),(count)))

#define __HAVE_ARCH_MEMSET
#define memset(s, c, count) \
(__builtin_constant_p(c) ? \
 __constant_c_x_memset((s),(0x01010101UL*(unsigned char)(c)),(count)) : \
 __memset((s),(c),(count)))

/*
 * 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;
}

#define __HAVE_ARCH_MOVEDATA
extern inline void movedata(unsigned src_seg, unsigned src_off,
		unsigned dst_seg, unsigned dst_off, size_t count)
{
	__asm__("pushl %%ds\n"
		"	movl %0,%%es\n"
		"	movl %1,%%ds\n"
/* xxx - handle overlapping src and dst */
		"	cld\n"
/* take care of odd-length (byte) */
		"	shr %%ecx\n"
		"	jnc 1f\n"
		"	movsb\n"
/* take care of word */
		"1:	shr %%ecx\n"
		"	jnc 2f\n"
		"	movsw\n"
/* now copy 32 bits at a time */
		"2:	rep\n"
		"	movsl\n"
		"popl %%ds\n"
		:
		: "m"(dst_seg), "m"(src_seg), "c"(count),
			"D"(dst_off), "S"(src_off));
}

#define  bcopy(src,dst,len) memcpy((src),(dst),(len))
#define  bzero(b,len) memset((void *)(b),0,(size_t)(len))

#endif