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, 184 insertions, 0 deletions

diff --git a/REORG.TODO/sysdeps/arm/armv6t2/memchr.S b/REORG.TODO/sysdeps/arm/armv6t2/memchr.S
new file mode 100644
index 0000000000..fb4dc8efa3
--- /dev/null
+++ b/REORG.TODO/sysdeps/arm/armv6t2/memchr.S
@@ -0,0 +1,184 @@
+/* Copyright (C) 2011-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Code contributed by Dave Gilbert <david.gilbert@linaro.org>
+
+   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/>.  */
+
+#include <sysdep.h>
+
+@ This memchr routine is optimised on a Cortex-A9 and should work on all ARMv7
+@ and ARMv6T2 processors.  It has a fast path for short sizes, and has an
+@ optimised path for large data sets; the worst case is finding the match early
+@ in a large data set.
+@ Note: The use of cbz/cbnz means it's Thumb only
+
+@ 2011-07-15 david.gilbert@linaro.org
+@    Copy from Cortex strings release 21 and change license
+@ http://bazaar.launchpad.net/~linaro-toolchain-dev/cortex-strings/trunk/view/head:/src/linaro-a9/memchr.S
+@    Change function declarations/entry/exit
+@ 2011-12-01 david.gilbert@linaro.org
+@    Add some fixes from comments received (including use of ldrd instead ldm)
+@ 2011-12-07 david.gilbert@linaro.org
+@    Removed cbz from align loop - can't be taken
+
+@ this lets us check a flag in a 00/ff byte easily in either endianness
+#ifdef __ARMEB__
+#define CHARTSTMASK(c) 1<<(31-(c*8))
+#else
+#define CHARTSTMASK(c) 1<<(c*8)
+#endif
+	.syntax unified
+
+	.text
+#ifdef NO_THUMB
+	.arm
+#else
+	.thumb
+	.thumb_func
+#endif
+	.global memchr
+	.type memchr,%function
+ENTRY(memchr)
+	@ r0 = start of memory to scan
+	@ r1 = character to look for
+	@ r2 = length
+	@ returns r0 = pointer to character or NULL if not found
+	and	r1,r1,#0xff	@ Don't think we can trust the caller to actually pass a char
+
+	cmp	r2,#16		@ If it's short don't bother with anything clever
+	blt	20f
+
+	tst	r0, #7		@ If it's already aligned skip the next bit
+	beq	10f
+
+	@ Work up to an aligned point
+5:
+	ldrb	r3, [r0],#1
+	subs	r2, r2, #1
+	cmp	r3, r1
+	beq	50f		@ If it matches exit found
+	tst	r0, #7
+	bne	5b		@ If not aligned yet then do next byte
+
+10:
+	@ At this point, we are aligned, we know we have at least 8 bytes to work with
+	push	{r4,r5,r6,r7}
+	cfi_adjust_cfa_offset (16)
+	cfi_rel_offset (r4, 0)
+	cfi_rel_offset (r5, 4)
+	cfi_rel_offset (r6, 8)
+	cfi_rel_offset (r7, 12)
+
+	cfi_remember_state
+
+	orr	r1, r1, r1, lsl #8	@ expand the match word across to all bytes
+	orr	r1, r1, r1, lsl #16
+	bic	r6, r2, #7	@ Number of double words to work with * 8
+	mvns	r7, #0		@ all F's
+	movs	r3, #0
+
+15:
+	ldrd 	r4,r5, [r0],#8
+#ifndef NO_THUMB
+	subs	r6, r6, #8
+#endif
+	eor	r4,r4, r1	@ Get it so that r4,r5 have 00's where the bytes match the target
+	eor	r5,r5, r1
+	uadd8	r4, r4, r7	@ Parallel add 0xff - sets the GE bits for anything that wasn't 0
+	sel	r4, r3, r7	@ bytes are 00 for none-00 bytes, or ff for 00 bytes - NOTE INVERSION
+	uadd8	r5, r5, r7	@ Parallel add 0xff - sets the GE bits for anything that wasn't 0
+	sel	r5, r4, r7	@ chained....bytes are 00 for none-00 bytes, or ff for 00 bytes - NOTE INVERSION
+#ifndef NO_THUMB
+	cbnz	r5, 60f
+#else
+	cmp	r5, #0
+	bne	60f
+	subs	r6, r6, #8
+#endif
+	bne	15b		@ (Flags from the subs above) If not run out of bytes then go around again
+
+	pop	{r4,r5,r6,r7}
+	cfi_adjust_cfa_offset (-16)
+	cfi_restore (r4)
+	cfi_restore (r5)
+	cfi_restore (r6)
+	cfi_restore (r7)
+
+	and	r1,r1,#0xff	@ Get r1 back to a single character from the expansion above
+	and	r2,r2,#7	@ Leave the count remaining as the number after the double words have been done
+
+20:
+#ifndef NO_THUMB
+	cbz	r2, 40f		@ 0 length or hit the end already then not found
+#else
+	cmp	r2, #0
+	beq	40f
+#endif
+
+21:  @ Post aligned section, or just a short call
+	ldrb	r3,[r0],#1
+#ifndef NO_THUMB
+	subs	r2,r2,#1
+	eor	r3,r3,r1	@ r3 = 0 if match - doesn't break flags from sub
+	cbz	r3, 50f
+#else
+	eors	r3, r3, r1
+	beq	50f
+	subs	r2, r2, #1
+#endif
+	bne	21b		@ on r2 flags
+
+40:
+	movs	r0,#0		@ not found
+	DO_RET(lr)
+
+50:
+	subs	r0,r0,#1	@ found
+	DO_RET(lr)
+
+60:  @ We're here because the fast path found a hit - now we have to track down exactly which word it was
+     @ r0 points to the start of the double word after the one that was tested
+     @ r4 has the 00/ff pattern for the first word, r5 has the chained value
+	cfi_restore_state
+	cmp	r4, #0
+	itte	eq
+	moveq	r4, r5		@ the end is in the 2nd word
+	subeq	r0,r0,#3	@ Points to 2nd byte of 2nd word
+	subne	r0,r0,#7	@ or 2nd byte of 1st word
+
+	@ r0 currently points to the 2nd byte of the word containing the hit
+	tst	r4, # CHARTSTMASK(0)	@ 1st character
+	bne	61f
+	adds	r0,r0,#1
+	tst	r4, # CHARTSTMASK(1)	@ 2nd character
+	ittt	eq
+	addeq	r0,r0,#1
+	tsteq	r4, # (3<<15)		@ 2nd & 3rd character
+	@ If not the 3rd must be the last one
+	addeq	r0,r0,#1
+
+61:
+	pop	{r4,r5,r6,r7}
+	cfi_adjust_cfa_offset (-16)
+	cfi_restore (r4)
+	cfi_restore (r5)
+	cfi_restore (r6)
+	cfi_restore (r7)
+
+	subs	r0,r0,#1
+	DO_RET(lr)
+
+END(memchr)
+libc_hidden_builtin_def (memchr)