initial import

1 files changed, 81 insertions, 0 deletions

diff --git a/sysdeps/i386/bzero.c b/sysdeps/i386/bzero.c
new file mode 100644
index 0000000000..659e54df22
--- /dev/null
+++ b/sysdeps/i386/bzero.c
@@ -0,0 +1,81 @@
+/* bzero -- set a block of memory to zero.
+   For Intel 80x86, x>=3.
+   Copyright (C) 1991, 1992, 1993 Free Software Foundation, Inc.
+   Contributed by Torbjorn Granlund (tege@sics.se).
+
+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 <ansidecl.h>
+#include <string.h>
+#include <memcopy.h>
+
+#undef	bzero
+
+#ifdef	__GNUC__
+
+void
+DEFUN(bzero, (dstpp, len),
+      PTR dstpp AND size_t len)
+{
+  /* N.B.: This code is almost verbatim from memset.c.  */
+
+  unsigned long int dstp = (unsigned long int) dstpp;
+
+  /* This explicit register allocation
+     improves code very much indeed.  */
+  register op_t x asm("ax");
+
+  x = 0;
+
+  /* Clear the direction flag, so filling will move forward.  */
+  asm volatile("cld");
+
+  /* This threshold value is optimal.  */
+  if (len >= 12)
+    {
+      /* Adjust LEN for the bytes handled in the first loop.  */
+      len -= (-dstp) % OPSIZ;
+
+      /* There are at least some bytes to set.
+	 No need to test for LEN == 0 in this alignment loop.  */
+
+      /* Fill bytes until DSTP is aligned on a longword boundary.  */
+      asm volatile("rep\n"
+		   "stosb" /* %0, %2, %3 */ :
+		   "=D" (dstp) :
+		   "0" (dstp), "c" ((-dstp) % OPSIZ), "a" (x) :
+		   "cx");
+
+      /* Fill longwords.  */
+      asm volatile("rep\n"
+		   "stosl" /* %0, %2, %3 */ :
+		   "=D" (dstp) :
+		   "0" (dstp), "c" (len / OPSIZ), "a" (x) :
+		   "cx");
+      len %= OPSIZ;
+    }
+
+  /* Write the last few bytes.  */
+  asm volatile("rep\n"
+	       "stosb" /* %0, %2, %3 */ :
+	       "=D" (dstp) :
+	       "0" (dstp), "c" (len), "a" (x) :
+	       "cx");
+}
+
+#else
+#include <sysdeps/generic/bzero.c>
+#endif