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String-handling functions for the new x86 setup code.

strcmp(), memcpy(), memset(), as well as routines to copy to and from
other segments (as pointed to by fs and gs).

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
H. Peter Anvin 2007-07-11 12:18:41 -07:00 committed by Linus Torvalds
parent ad7e906d56
commit 5be8656615
2 changed files with 153 additions and 0 deletions
arch/i386/boot

101
arch/i386/boot/copy.S Normal file
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/* ----------------------------------------------------------------------- *
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright 2007 rPath, Inc. - All Rights Reserved
*
* This file is part of the Linux kernel, and is made available under
* the terms of the GNU General Public License version 2.
*
* ----------------------------------------------------------------------- */
/*
* arch/i386/boot/copy.S
*
* Memory copy routines
*/
.code16gcc
.text
.globl memcpy
.type memcpy, @function
memcpy:
pushw %si
pushw %di
movw %ax, %di
movw %dx, %si
pushw %cx
shrw $2, %cx
rep; movsl
popw %cx
andw $3, %cx
rep; movsb
popw %di
popw %si
ret
.size memcpy, .-memcpy
.globl memset
.type memset, @function
memset:
pushw %di
movw %ax, %di
movzbl %dl, %eax
imull $0x01010101,%eax
pushw %cx
shrw $2, %cx
rep; stosl
popw %cx
andw $3, %cx
rep; stosb
popw %di
ret
.size memset, .-memset
.globl copy_from_fs
.type copy_from_fs, @function
copy_from_fs:
pushw %ds
pushw %fs
popw %ds
call memcpy
popw %ds
ret
.size copy_from_fs, .-copy_from_fs
.globl copy_to_fs
.type copy_to_fs, @function
copy_to_fs:
pushw %es
pushw %fs
popw %es
call memcpy
popw %es
ret
.size copy_to_fs, .-copy_to_fs
#if 0 /* Not currently used, but can be enabled as needed */
.globl copy_from_gs
.type copy_from_gs, @function
copy_from_gs:
pushw %ds
pushw %gs
popw %ds
call memcpy
popw %ds
ret
.size copy_from_gs, .-copy_from_gs
.globl copy_to_gs
.type copy_to_gs, @function
copy_to_gs:
pushw %es
pushw %gs
popw %es
call memcpy
popw %es
ret
.size copy_to_gs, .-copy_to_gs
#endif

52
arch/i386/boot/string.c Normal file
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/* -*- linux-c -*- ------------------------------------------------------- *
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright 2007 rPath, Inc. - All Rights Reserved
*
* This file is part of the Linux kernel, and is made available under
* the terms of the GNU General Public License version 2.
*
* ----------------------------------------------------------------------- */
/*
* arch/i386/boot/string.c
*
* Very basic string functions
*/
#include "boot.h"
int strcmp(const char *str1, const char *str2)
{
const unsigned char *s1 = (const unsigned char *)str1;
const unsigned char *s2 = (const unsigned char *)str2;
int delta = 0;
while (*s1 || *s2) {
delta = *s2 - *s1;
if (delta)
return delta;
s1++;
s2++;
}
return 0;
}
size_t strnlen(const char *s, size_t maxlen)
{
const char *es = s;
while (*es && maxlen) {
es++;
maxlen--;
}
return (es - s);
}
unsigned int atou(const char *s)
{
unsigned int i = 0;
while (isdigit(*s))
i = i * 10 + (*s++ - '0');
return i;
}