glibc/string/strncpy.c
H.J. Lu ab6a873fe0 SSSE3 strcpy/stpcpy for x86-64
This patch adds SSSE3 strcpy/stpcpy. I got up to 4X speed up on Core 2
and Core i7.  I disabled it on Atom since SSSE3 version is slower for
shorter (<64byte) data.
2009-07-02 03:39:03 -07:00

89 lines
1.7 KiB
C

/* Copyright (C) 1991, 1997, 2003 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 Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <string.h>
#include <memcopy.h>
#undef strncpy
#ifndef STRNCPY
#define STRNCPY strncpy
#endif
char *
STRNCPY (char *s1, const char *s2, size_t n)
{
reg_char c;
char *s = s1;
--s1;
if (n >= 4)
{
size_t n4 = n >> 2;
for (;;)
{
c = *s2++;
*++s1 = c;
if (c == '\0')
break;
c = *s2++;
*++s1 = c;
if (c == '\0')
break;
c = *s2++;
*++s1 = c;
if (c == '\0')
break;
c = *s2++;
*++s1 = c;
if (c == '\0')
break;
if (--n4 == 0)
goto last_chars;
}
n = n - (s1 - s) - 1;
if (n == 0)
return s;
goto zero_fill;
}
last_chars:
n &= 3;
if (n == 0)
return s;
do
{
c = *s2++;
*++s1 = c;
if (--n == 0)
return s;
}
while (c != '\0');
zero_fill:
do
*++s1 = '\0';
while (--n > 0);
return s;
}
libc_hidden_builtin_def (strncpy)