Have memmove call __builtin_memcopy on PowerPC if src and dest don't overlap.

2025-02-23 13:09:58 +08:00 · 2012-04-18 16:44:27 -05:00 · 2012-04-18 16:44:27 -05:00 · 8ff41c4601
commit 8ff41c4601
parent 6b652f46c3
2 changed files with 125 additions and 0 deletions
--- a/6
+++ b/6
@ -1,3 +1,9 @@
+2012-04-18  Will Schmidt  <will_schmidt@vnet.ibm.com>
+
+	* sysdeps/powerpc/memmove.c: New file based on string/memmove.c where
+	__builtin_memcopy is called when src and dest ranges are known to not
+	overlap.
+
 2012-04-18  Will Schmidt  <will_schmidt@vnet.ibm.com>

 	* sysdeps/powerpc/powerpc64/power6/wordcopy.c
--- a/sysdeps/powerpc/memmove.c
+++ b/sysdeps/powerpc/memmove.c
@ -0,0 +1,119 @@
+/* Copy memory to memory until the specified number of bytes
+   has been copied.  Overlap is handled correctly.
+   Copyright (C) 1991-2012 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   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 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.  */
+
+#include <string.h>
+#include <memcopy.h>
+#include <pagecopy.h>
+
+/* All this is so that bcopy.c can #include
+   this file after defining some things.  */
+#ifndef        a1
+#define        a1      dest    /* First arg is DEST.  */
+#define        a1const
+#define        a2      src     /* Second arg is SRC.  */
+#define        a2const const
+#undef memmove
+#endif
+#if    !defined(RETURN) || !defined(rettype)
+#define        RETURN(s)       return (s)      /* Return DEST.  */
+#define        rettype         void *
+#endif
+
+#ifndef MEMMOVE
+#define MEMMOVE memmove
+#endif
+
+rettype
+MEMMOVE (a1, a2, len)
+     a1const void *a1;
+     a2const void *a2;
+     size_t len;
+{
+  unsigned long int dstp = (long int) dest;
+  unsigned long int srcp = (long int) src;
+
+  /* If there is no overlap between ranges, call the builtin memcpy.  */
+  if ( (dstp >= (srcp + len)) || (srcp > (dstp + len)) )
+    return __builtin_memcpy (dest, src, len);
+
+  /* This test makes the forward copying code be used whenever possible.
+     Reduces the working set.  */
+  if (dstp - srcp >= len)      /* *Unsigned* compare!  */
+    {
+      /* Copy from the beginning to the end.  */
+
+      /* If there not too few bytes to copy, use word copy.  */
+      if (len >= OP_T_THRES)
+       {
+         /* Copy just a few bytes to make DSTP aligned.  */
+         len -= (-dstp) % OPSIZ;
+         BYTE_COPY_FWD (dstp, srcp, (-dstp) % OPSIZ);
+
+         /* Copy whole pages from SRCP to DSTP by virtual address
+            manipulation, as much as possible.  */
+
+         PAGE_COPY_FWD_MAYBE (dstp, srcp, len, len);
+
+         /* Copy from SRCP to DSTP taking advantage of the known
+            alignment of DSTP.  Number of bytes remaining is put
+            in the third argument, i.e. in LEN.  This number may
+            vary from machine to machine.  */
+
+         WORD_COPY_FWD (dstp, srcp, len, len);
+
+         /* Fall out and copy the tail.  */
+       }
+
+      /* There are just a few bytes to copy.  Use byte memory operations.  */
+      BYTE_COPY_FWD (dstp, srcp, len);
+    }
+  else
+    {
+      /* Copy from the end to the beginning.  */
+      srcp += len;
+      dstp += len;
+
+      /* If there not too few bytes to copy, use word copy.  */
+      if (len >= OP_T_THRES)
+       {
+         /* Copy just a few bytes to make DSTP aligned.  */
+         len -= dstp % OPSIZ;
+         BYTE_COPY_BWD (dstp, srcp, dstp % OPSIZ);
+
+         /* Copy from SRCP to DSTP taking advantage of the known
+            alignment of DSTP.  Number of bytes remaining is put
+            in the third argument, i.e. in LEN.  This number may
+            vary from machine to machine.  */
+
+         WORD_COPY_BWD (dstp, srcp, len, len);
+
+         /* Fall out and copy the tail.  */
+       }
+
+      /* There are just a few bytes to copy.  Use byte memory operations.  */
+      BYTE_COPY_BWD (dstp, srcp, len);
+    }
+
+  RETURN (dest);
+}
+#ifndef memmove
+libc_hidden_builtin_def (memmove)
+#endif