Prepare for radical source tree reorganization.zack/build-layout-experiment

All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).

1 files changed, 202 insertions, 0 deletions

diff --git a/REORG.TODO/sysdeps/generic/memcopy.h b/REORG.TODO/sysdeps/generic/memcopy.h
new file mode 100644
index 0000000000..83b8fd6de8
--- /dev/null
+++ b/REORG.TODO/sysdeps/generic/memcopy.h
@@ -0,0 +1,202 @@
+/* memcopy.h -- definitions for memory copy functions.  Generic C version.
+   Copyright (C) 1991-2017 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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _MEMCOPY_H
+#define _MEMCOPY_H	1
+
+/* The strategy of the memory functions is:
+
+     1. Copy bytes until the destination pointer is aligned.
+
+     2. Copy words in unrolled loops.  If the source and destination
+     are not aligned in the same way, use word memory operations,
+     but shift and merge two read words before writing.
+
+     3. Copy the few remaining bytes.
+
+   This is fast on processors that have at least 10 registers for
+   allocation by GCC, and that can access memory at reg+const in one
+   instruction.
+
+   I made an "exhaustive" test of this memmove when I wrote it,
+   exhaustive in the sense that I tried all alignment and length
+   combinations, with and without overlap.  */
+
+#include <sys/cdefs.h>
+#include <endian.h>
+#include <pagecopy.h>
+
+/* The macros defined in this file are:
+
+   BYTE_COPY_FWD(dst_beg_ptr, src_beg_ptr, nbytes_to_copy)
+
+   BYTE_COPY_BWD(dst_end_ptr, src_end_ptr, nbytes_to_copy)
+
+   WORD_COPY_FWD(dst_beg_ptr, src_beg_ptr, nbytes_remaining, nbytes_to_copy)
+
+   WORD_COPY_BWD(dst_end_ptr, src_end_ptr, nbytes_remaining, nbytes_to_copy)
+
+   MERGE(old_word, sh_1, new_word, sh_2)
+     [I fail to understand.  I feel stupid.  --roland]
+*/
+
+/* Type to use for aligned memory operations.
+   This should normally be the biggest type supported by a single load
+   and store.  */
+#define	op_t	unsigned long int
+#define OPSIZ	(sizeof(op_t))
+
+/* Type to use for unaligned operations.  */
+typedef unsigned char byte;
+
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+#define MERGE(w0, sh_1, w1, sh_2) (((w0) >> (sh_1)) | ((w1) << (sh_2)))
+#endif
+#if __BYTE_ORDER == __BIG_ENDIAN
+#define MERGE(w0, sh_1, w1, sh_2) (((w0) << (sh_1)) | ((w1) >> (sh_2)))
+#endif
+
+/* Copy exactly NBYTES bytes from SRC_BP to DST_BP,
+   without any assumptions about alignment of the pointers.  */
+#define BYTE_COPY_FWD(dst_bp, src_bp, nbytes)				      \
+  do									      \
+    {									      \
+      size_t __nbytes = (nbytes);					      \
+      while (__nbytes > 0)						      \
+	{								      \
+	  byte __x = ((byte *) src_bp)[0];				      \
+	  src_bp += 1;							      \
+	  __nbytes -= 1;						      \
+	  ((byte *) dst_bp)[0] = __x;					      \
+	  dst_bp += 1;							      \
+	}								      \
+    } while (0)
+
+/* Copy exactly NBYTES_TO_COPY bytes from SRC_END_PTR to DST_END_PTR,
+   beginning at the bytes right before the pointers and continuing towards
+   smaller addresses.  Don't assume anything about alignment of the
+   pointers.  */
+#define BYTE_COPY_BWD(dst_ep, src_ep, nbytes)				      \
+  do									      \
+    {									      \
+      size_t __nbytes = (nbytes);					      \
+      while (__nbytes > 0)						      \
+	{								      \
+	  byte __x;							      \
+	  src_ep -= 1;							      \
+	  __x = ((byte *) src_ep)[0];					      \
+	  dst_ep -= 1;							      \
+	  __nbytes -= 1;						      \
+	  ((byte *) dst_ep)[0] = __x;					      \
+	}								      \
+    } while (0)
+
+/* Copy *up to* NBYTES bytes from SRC_BP to DST_BP, with
+   the assumption that DST_BP is aligned on an OPSIZ multiple.  If
+   not all bytes could be easily copied, store remaining number of bytes
+   in NBYTES_LEFT, otherwise store 0.  */
+extern void _wordcopy_fwd_aligned (long int, long int, size_t)
+  attribute_hidden __THROW;
+extern void _wordcopy_fwd_dest_aligned (long int, long int, size_t)
+  attribute_hidden __THROW;
+#define WORD_COPY_FWD(dst_bp, src_bp, nbytes_left, nbytes)		      \
+  do									      \
+    {									      \
+      if (src_bp % OPSIZ == 0)						      \
+	_wordcopy_fwd_aligned (dst_bp, src_bp, (nbytes) / OPSIZ);	      \
+      else								      \
+	_wordcopy_fwd_dest_aligned (dst_bp, src_bp, (nbytes) / OPSIZ);	      \
+      src_bp += (nbytes) & -OPSIZ;					      \
+      dst_bp += (nbytes) & -OPSIZ;					      \
+      (nbytes_left) = (nbytes) % OPSIZ;					      \
+    } while (0)
+
+/* Copy *up to* NBYTES_TO_COPY bytes from SRC_END_PTR to DST_END_PTR,
+   beginning at the words (of type op_t) right before the pointers and
+   continuing towards smaller addresses.  May take advantage of that
+   DST_END_PTR is aligned on an OPSIZ multiple.  If not all bytes could be
+   easily copied, store remaining number of bytes in NBYTES_REMAINING,
+   otherwise store 0.  */
+extern void _wordcopy_bwd_aligned (long int, long int, size_t)
+  attribute_hidden __THROW;
+extern void _wordcopy_bwd_dest_aligned (long int, long int, size_t)
+  attribute_hidden __THROW;
+#define WORD_COPY_BWD(dst_ep, src_ep, nbytes_left, nbytes)		      \
+  do									      \
+    {									      \
+      if (src_ep % OPSIZ == 0)						      \
+	_wordcopy_bwd_aligned (dst_ep, src_ep, (nbytes) / OPSIZ);	      \
+      else								      \
+	_wordcopy_bwd_dest_aligned (dst_ep, src_ep, (nbytes) / OPSIZ);	      \
+      src_ep -= (nbytes) & -OPSIZ;					      \
+      dst_ep -= (nbytes) & -OPSIZ;					      \
+      (nbytes_left) = (nbytes) % OPSIZ;					      \
+    } while (0)
+
+/* The macro PAGE_COPY_FWD_MAYBE (dstp, srcp, nbytes_left, nbytes) is invoked
+   like WORD_COPY_FWD et al.  The pointers should be at least word aligned.
+   This will check if virtual copying by pages can and should be done and do it
+   if so.  The pointers will be aligned to PAGE_SIZE bytes.  The macro requires
+   that pagecopy.h defines at least PAGE_COPY_THRESHOLD to 0.  If
+   PAGE_COPY_THRESHOLD is non-zero, the header must also define PAGE_COPY_FWD
+   and PAGE_SIZE.
+*/
+#if PAGE_COPY_THRESHOLD
+
+# include <assert.h>
+
+# define PAGE_COPY_FWD_MAYBE(dstp, srcp, nbytes_left, nbytes)		      \
+  do									      \
+    {									      \
+      if ((nbytes) >= PAGE_COPY_THRESHOLD &&				      \
+	  PAGE_OFFSET ((dstp) - (srcp)) == 0) 				      \
+	{								      \
+	  /* The amount to copy is past the threshold for copying	      \
+	     pages virtually with kernel VM operations, and the		      \
+	     source and destination addresses have the same alignment.  */    \
+	  size_t nbytes_before = PAGE_OFFSET (-(dstp));			      \
+	  if (nbytes_before != 0)					      \
+	    {								      \
+	      /* First copy the words before the first page boundary.  */     \
+	      WORD_COPY_FWD (dstp, srcp, nbytes_left, nbytes_before);	      \
+	      assert (nbytes_left == 0);				      \
+	      nbytes -= nbytes_before;					      \
+	    }								      \
+	  PAGE_COPY_FWD (dstp, srcp, nbytes_left, nbytes);		      \
+	}								      \
+    } while (0)
+
+/* The page size is always a power of two, so we can avoid modulo division.  */
+# define PAGE_OFFSET(n)	((n) & (PAGE_SIZE - 1))
+
+#else
+
+# define PAGE_COPY_FWD_MAYBE(dstp, srcp, nbytes_left, nbytes) /* nada */
+
+#endif
+
+/* Threshold value for when to enter the unrolled loops.  */
+#define	OP_T_THRES	16
+
+/* Set to 1 if memcpy is safe to use for forward-copying memmove with
+   overlapping addresses.  This is 0 by default because memcpy implementations
+   are generally not safe for overlapping addresses.  */
+#define MEMCPY_OK_FOR_FWD_MEMMOVE 0
+
+#endif /* memcopy.h */