newlib/libc/machine/riscv/strcpy.c

   1 /* Copyright (c) 2017  SiFive Inc. All rights reserved.
   2
   3    This copyrighted material is made available to anyone wishing to use,
   4    modify, copy, or redistribute it subject to the terms and conditions
   5    of the FreeBSD License.   This program is distributed in the hope that
   6    it will be useful, but WITHOUT ANY WARRANTY expressed or implied,
   7    including the implied warranties of MERCHANTABILITY or FITNESS FOR
   8    A PARTICULAR PURPOSE.  A copy of this license is available at
   9    http://www.opensource.org/licenses.
  10 */
  11
  12 #include <string.h>
  13 #include <stdint.h>
  14
  15 char *strcpy(char *dst, const char *src)
  16 {
  17   char *dst0 = dst;
  18
  19 #if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__)
  20   int misaligned = ((uintptr_t)dst | (uintptr_t)src) & (sizeof (long) - 1);
  21   if (__builtin_expect(!misaligned, 1))
  22     {
  23       long *ldst = (long *)dst;
  24       const long *lsrc = (const long *)src;
  25
  26       while (!__libc_detect_null(*lsrc))
  27         *ldst++ = *lsrc++;
  28
  29       dst = (char *)ldst;
  30       src = (const char *)lsrc;
  31
  32       char c0 = src[0];
  33       char c1 = src[1];
  34       char c2 = src[2];
  35       if (!(*dst++ = c0)) return dst0;
  36       if (!(*dst++ = c1)) return dst0;
  37       char c3 = src[3];
  38       if (!(*dst++ = c2)) return dst0;
  39       if (sizeof (long) == 4) goto out;
  40       char c4 = src[4];
  41       if (!(*dst++ = c3)) return dst0;
  42       char c5 = src[5];
  43       if (!(*dst++ = c4)) return dst0;
  44       char c6 = src[6];
  45       if (!(*dst++ = c5)) return dst0;
  46       if (!(*dst++ = c6)) return dst0;
  47
  48 out:
  49       *dst++ = 0;
  50       return dst0;
  51     }
  52 #endif /* not PREFER_SIZE_OVER_SPEED */
  53
  54   char ch;
  55   do
  56     {
  57       ch = *src;
  58       src++;
  59       dst++;
  60       *(dst - 1) = ch;
  61     } while (ch);
  62
  63   return dst0;
  64 }