commit 3ec7d8a6b30659b34693730a374c0265a191c4ba

Author: Kyle McMartin <kyle@mcmartin.ca>

Date:   Wed Dec 3 12:26:23 2014 -0500

    Revert "[AArch64] Add optimized strchrnul."

    This reverts commit be9d4ccc7fe62751db1a5fdcb31958561dbbda9a.

diff --git a/sysdeps/aarch64/strchrnul.S b/sysdeps/aarch64/strchrnul.S

deleted file mode 100644

index b98c2e9..0000000

--- a/sysdeps/aarch64/strchrnul.S

+++ /dev/null

@@ -1,130 +0,0 @@

-/* strchrnul - find a character or nul in a string

-

-   Copyright (C) 2014 Free Software Foundation, Inc.

-

-   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/>.  */

-

-#include <sysdep.h>

-

-/* Assumptions:

- *

- * ARMv8-a, AArch64

- * Neon Available.

- */

-

-/* Arguments and results.  */

-#define srcin		x0

-#define chrin		w1

-

-#define result		x0

-

-/* Locals and temporaries.  */

-

-#define src		x2

-#define tmp1		x3

-#define wtmp2		w4

-#define tmp3		x5

-

-#define vrepchr		v0

-#define vdata1		v1

-#define vdata2		v2

-#define vhas_nul1	v3

-#define vhas_nul2	v4

-#define vhas_chr1	v5

-#define vhas_chr2	v6

-#define vrepmask	v15

-#define vend1		v16

-

-/* Core algorithm.

-

-   For each 32-byte hunk we calculate a 64-bit syndrome value, with

-   two bits per byte (LSB is always in bits 0 and 1, for both big

-   and little-endian systems).  For each tuple, bit 0 is set iff

-   the relevant byte matched the requested character or nul.  Since the

-   bits in the syndrome reflect exactly the order in which things occur

-   in the original string a count_trailing_zeros() operation will

-   identify exactly which byte is causing the termination.  */

-

-ENTRY (__strchrnul)

-	/* Magic constant 0x40100401 to allow us to identify which lane

-	   matches the termination condition.  */

-	mov	wtmp2, #0x0401

-	movk	wtmp2, #0x4010, lsl #16

-	dup	vrepchr.16b, chrin

-	bic	src, srcin, #31		/* Work with aligned 32-byte hunks.  */

-	dup	vrepmask.4s, wtmp2

-	ands	tmp1, srcin, #31

-	b.eq	L(loop)

-

-	/* Input string is not 32-byte aligned.  Rather than forcing

-	   the padding bytes to a safe value, we calculate the syndrome

-	   for all the bytes, but then mask off those bits of the

-	   syndrome that are related to the padding.  */

-	ld1	{vdata1.16b, vdata2.16b}, [src], #32

-	neg	tmp1, tmp1

-	cmeq	vhas_nul1.16b, vdata1.16b, #0

-	cmeq	vhas_chr1.16b, vdata1.16b, vrepchr.16b

-	cmeq	vhas_nul2.16b, vdata2.16b, #0

-	cmeq	vhas_chr2.16b, vdata2.16b, vrepchr.16b

-	orr	vhas_chr1.16b, vhas_chr1.16b, vhas_nul1.16b

-	orr	vhas_chr2.16b, vhas_chr2.16b, vhas_nul2.16b

-	and	vhas_chr1.16b, vhas_chr1.16b, vrepmask.16b

-	and	vhas_chr2.16b, vhas_chr2.16b, vrepmask.16b

-	lsl	tmp1, tmp1, #1

-	addp	vend1.16b, vhas_chr1.16b, vhas_chr2.16b	// 256->128

-	mov	tmp3, #~0

-	addp	vend1.16b, vend1.16b, vend1.16b		// 128->64

-	lsr	tmp1, tmp3, tmp1

-

-	mov	tmp3, vend1.2d[0]

-	bic	tmp1, tmp3, tmp1	// Mask padding bits.

-	cbnz	tmp1, L(tail)

-

-L(loop):

-	ld1	{vdata1.16b, vdata2.16b}, [src], #32

-	cmeq	vhas_nul1.16b, vdata1.16b, #0

-	cmeq	vhas_chr1.16b, vdata1.16b, vrepchr.16b

-	cmeq	vhas_nul2.16b, vdata2.16b, #0

-	cmeq	vhas_chr2.16b, vdata2.16b, vrepchr.16b

-	/* Use a fast check for the termination condition.  */

-	orr	vhas_chr1.16b, vhas_nul1.16b, vhas_chr1.16b

-	orr	vhas_chr2.16b, vhas_nul2.16b, vhas_chr2.16b

-	orr	vend1.16b, vhas_chr1.16b, vhas_chr2.16b

-	addp	vend1.2d, vend1.2d, vend1.2d

-	mov	tmp1, vend1.2d[0]

-	cbz	tmp1, L(loop)

-

-	/* Termination condition found.  Now need to establish exactly why

-	   we terminated.  */

-	and	vhas_chr1.16b, vhas_chr1.16b, vrepmask.16b

-	and	vhas_chr2.16b, vhas_chr2.16b, vrepmask.16b

-	addp	vend1.16b, vhas_chr1.16b, vhas_chr2.16b		// 256->128

-	addp	vend1.16b, vend1.16b, vend1.16b		// 128->64

-

-	mov	tmp1, vend1.2d[0]

-L(tail):

-	/* Count the trailing zeros, by bit reversing...  */

-	rbit	tmp1, tmp1

-	/* Re-bias source.  */

-	sub	src, src, #32

-	clz	tmp1, tmp1	/* ... and counting the leading zeros.  */

-	/* tmp1 is twice the offset into the fragment.  */

-	add	result, src, tmp1, lsr #1

-	ret

-

-END(__strchrnul)

-weak_alias (__strchrnul, strchrnul)