initial import

1 files changed, 86 insertions, 0 deletions

diff --git a/sysdeps/alpha/memchr.c b/sysdeps/alpha/memchr.c
new file mode 100644
index 0000000000..11ff542f25
--- /dev/null
+++ b/sysdeps/alpha/memchr.c
@@ -0,0 +1,86 @@
+/* Copyright (C) 1992, 1993, 1994 Free Software Foundation, Inc.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <string.h>
+
+/* Search no more than N bytes of S for C.  */
+
+void *
+memchr (const void *s, int c, size_t n)
+{
+  const char *char_ptr;
+  const unsigned long int *longword_ptr;
+  unsigned long int charmask;
+  size_t x;
+
+  c = (unsigned char) c;
+
+  /* Handle the first few characters by reading one character at a time.
+     Do this until STR is aligned on a 8-byte border.  */
+  for (char_ptr = s; n > 0 && ((unsigned long int) char_ptr & 7) != 0;
+       --n, ++char_ptr)
+    if (*char_ptr == c)
+      return (void *) char_ptr;
+
+  if (n == (size_t)0)
+    return NULL;
+
+  x = n;
+
+  longword_ptr = (unsigned long int *) char_ptr;
+
+  /* Set up a longword, each of whose bytes is C.  */
+  charmask = c | (c << 8);
+  charmask |= charmask << 16;
+  charmask |= charmask << 32;
+
+  for (;;)
+    {
+      const unsigned long int longword = *longword_ptr++;
+      int ge, le;
+
+      if (x < 4)
+	x = (size_t) 0;
+      else
+	x -= 4;
+
+      /* Set bits in GE if bytes in CHARMASK are >= bytes in LONGWORD.  */
+      asm ("cmpbge %1, %2, %0" : "=r" (ge) : "r" (charmask), "r" (longword));
+
+      /* Set bits in LE if bytes in CHARMASK are <= bytes in LONGWORD.  */
+      asm ("cmpbge %2, %1, %0" : "=r" (le) : "r" (charmask), "r" (longword));
+
+      /* Bytes that are both <= and >= are == to C.  */
+      if (ge & le)
+	{
+	  /* Which of the bytes was the C?  */
+
+	  unsigned char *cp = (unsigned char *) (longword_ptr - 1);
+	  int i;
+
+	  for (i = 0; i < 6; i++)
+	    if (cp[i] == c)
+	      return &cp[i];
+	  return &cp[7];
+	}
+
+      if (x == (size_t)0)
+	break;
+    }
+
+  return NULL;
+}