glibc/string/stpncpy.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

102 lines
2.1 KiB
C

/* Copyright (C) 1993, 1995, 1996, 1997, 2002 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. */
/* This is almost copied from strncpy.c, written by Torbjorn Granlund. */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#ifdef _LIBC
# include <string.h>
#else
# include <sys/types.h>
#endif
#ifndef STPNCPY
# ifdef weak_alias
# define STPNCPY __stpncpy
weak_alias (__stpncpy, stpncpy)
# else
# define STPNCPY stpncpy
# endif
#endif
/* Copy no more than N characters of SRC to DEST, returning the address of
the terminating '\0' in DEST, if any, or else DEST + N. */
char *
STPNCPY (char *dest, const char *src, size_t n)
{
char c;
char *s = dest;
if (n >= 4)
{
size_t n4 = n >> 2;
for (;;)
{
c = *src++;
*dest++ = c;
if (c == '\0')
break;
c = *src++;
*dest++ = c;
if (c == '\0')
break;
c = *src++;
*dest++ = c;
if (c == '\0')
break;
c = *src++;
*dest++ = c;
if (c == '\0')
break;
if (--n4 == 0)
goto last_chars;
}
n -= dest - s;
goto zero_fill;
}
last_chars:
n &= 3;
if (n == 0)
return dest;
for (;;)
{
c = *src++;
--n;
*dest++ = c;
if (c == '\0')
break;
if (n == 0)
return dest;
}
zero_fill:
while (n-- > 0)
dest[n] = '\0';
return dest - 1;
}
#ifdef weak_alias
libc_hidden_def (__stpncpy)
#endif