Subversion Repositories openrisc_2011-10-31

/*

 * strcmp.c -- strcmp function.  On at least some MIPS chips, a strcmp that is

 * unrolled twice is faster than the 'optimized' C version in newlib.

 *

 * Copyright (c) 2001 Red Hat, Inc.

 *

 * The authors hereby grant permission to use, copy, modify, distribute,

 * and license this software and its documentation for any purpose, provided

 * that existing copyright notices are retained in all copies and that this

 * notice is included verbatim in any distributions. No written agreement,

 * license, or royalty fee is required for any of the authorized uses.

 * Modifications to this software may be copyrighted by their authors

 * and need not follow the licensing terms described here, provided that

 * the new terms are clearly indicated on the first page of each file where

 * they apply.  */

#include <stddef.h>

#include <string.h>

#include <stdlib.h>

int

strcmp (const char *s1, const char *s2)

{

  unsigned const char *us1 = (unsigned const char *)s1;

  unsigned const char *us2 = (unsigned const char *)s2;

  int c1a, c1b;

  int c2a, c2b;

  /* If the pointers aren't both aligned to a 16-byte boundary, do the

     comparison byte by byte, so that we don't get an invalid page fault if we

     are comparing a string whose null byte is at the last byte on the last

     valid page.  */

  if (((((long)us1) | ((long)us2)) & 1) == 0)

    {

      c1a = *us1;

      for (;;)

        {

          c1b = *us2;

          us1 += 2;

          if (c1a == '\0')

            goto ret1;

          c2a = us1[-1];

          if (c1a != c1b)

            goto ret1;

          c2b = us2[1];

          us2 += 2;

          if (c2a == '\0')

            break;

          c1a = *us1;

          if (c2a != c2b)

            break;

        }

      return c2a - c2b;

    }

  else

    {

      do

        {

          c1a = *us1++;

          c1b = *us2++;

        }

      while (c1a != '\0' && c1a == c1b);

    }

 ret1:

  return c1a - c1b;

}