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, 127 insertions, 0 deletions

diff --git a/REORG.TODO/sysdeps/alpha/memset.S b/REORG.TODO/sysdeps/alpha/memset.S
new file mode 100644
index 0000000000..2e061b90e6
--- /dev/null
+++ b/REORG.TODO/sysdeps/alpha/memset.S
@@ -0,0 +1,127 @@
+/* Copyright (C) 1996-2017 Free Software Foundation, Inc.
+   Contributed by Richard Henderson (rth@tamu.edu)
+   This file is part of the GNU C Library.
+
+   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/>.  */
+
+/* Fill a block of memory with a character.  Optimized for the Alpha
+   architecture:
+
+   - memory accessed as aligned quadwords only
+   - destination memory not read unless needed for good cache behaviour
+   - basic blocks arranged to optimize branch prediction for full-quadword
+     aligned memory blocks.
+   - partial head and tail quadwords constructed with byte-mask instructions
+
+   This is generally scheduled for the EV5 (got to look out for my own
+   interests :-), but with EV4 needs in mind.  There *should* be no more
+   stalls for the EV4 than there are for the EV5.
+*/
+
+
+#include <sysdep.h>
+
+	.set noat
+	.set noreorder
+
+	.text
+	.type	memset, @function
+	.globl	memset
+	.usepv	memset, USEPV_PROF
+
+	cfi_startproc
+
+	/* On entry to this basic block:
+	   t3 == loop counter
+	   t4 == bytes in partial final word
+	   a0 == possibly misaligned destination pointer
+	   a1 == replicated source character  */
+
+	.align 3
+memset_loop:
+	beq	t3, $tail
+	blbc	t3, 0f		# skip single store if count even
+
+	stq_u	a1, 0(a0)	# e0    : store one word
+	subq	t3, 1, t3	# .. e1 :
+	addq	a0, 8, a0	# e0    :
+	beq	t3, $tail	# .. e1 :
+
+0:	stq_u	a1, 0(a0)	# e0    : store two words
+	subq	t3, 2, t3	# .. e1 :
+	stq_u	a1, 8(a0)	# e0    :
+	addq	a0, 16, a0	# .. e1 :
+	bne	t3, 0b		# e1    :
+
+$tail:	bne	t4, 1f		# is there a tail to do?
+	ret			# no
+
+	.align 3
+1:	ldq_u	t0, 0(a0)	# e1    : yes, load original data
+	mskql	a1, t4, t1	# .. e0 :
+	mskqh	t0, t4, t0	# e0    :
+	or	t0, t1, t0	# e1 (stall)
+	stq_u	t0, 0(a0)	# e0    :
+	ret			# .. e1 :
+
+memset:
+#ifdef PROF
+	ldgp	gp, 0(pv)
+	lda	AT, _mcount
+	jsr	AT, (AT), _mcount
+#endif
+
+	and	a1, 0xff, a1	# e0    : zero extend input character
+	mov	a0, v0		# .. e1 : move return value in place
+	sll	a1, 8, t0	# e0    : begin replicating the char
+	beq	a2, $done	# .. e1 : early exit for zero-length store
+	or	t0, a1, a1	# e0    :
+	and	a0, 7, t1	# .. e1 : dest misalignment
+	sll	a1, 16, t0	# e0    :
+	addq	a2, t1, a2	# .. e1 : add dest misalignment to count
+	or	t0, a1, a1	# e0    :
+	srl	a2, 3, t3	# .. e1 : loop = count >> 3
+	sll	a1, 32, t0	# e0    :
+	and	a2, 7, t4	# .. e1 : find number of bytes in tail
+	or	t0, a1, a1	# e0    : character replication done
+
+	beq	t1, memset_loop	# .. e1 : aligned head, jump right in
+
+	ldq_u	t0, 0(a0)	# e1    : load original data to mask into
+	mskqh	a1, a0, t1	# .. e0 :
+
+	cmpult	a2, 8, t2	# e0    : is this a sub-word set?
+	bne	t2, $oneq	# .. e1 (zdb)
+
+	mskql	t0, a0, t0	# e0    : we span words.  finish this partial
+	subq	t3, 1, t3	# .. e1 :
+	addq	a0, 8, a0	# e0    :
+	or	t0, t1, t0	# .. e1 :
+	stq_u	t0, -8(a0)	# e0    :
+	br 	memset_loop	# .. e1 :
+
+	.align 3
+$oneq:
+	mskql	t1, a2, t1	# e0    : entire operation within one word
+	mskql	t0, a0, t2	# e0    :
+	mskqh	t0, a2, t3	# e0    :
+	or	t1, t2, t0	# .. e1 :
+	or	t0, t3, t0	# e1    :
+	stq_u	t0, 0(a0)	# e0 (stall)
+
+$done:	ret
+
+	cfi_endproc
+libc_hidden_builtin_def (memset)