minix/common/lib/libc/arch/arm/string/strlen_neon.S
Lionel Sambuc 84d9c625bf Synchronize on NetBSD-CVS (2013/12/1 12:00:00 UTC)
- Fix for possible unset uid/gid in toproto
 - Fix for default mtree style
 - Update libelf
 - Importing libexecinfo
 - Resynchronize GCC, mpc, gmp, mpfr
 - build.sh: Replace params with show-params.
     This has been done as the make target has been renamed in the same
     way, while a new target named params has been added. This new
     target generates a file containing all the parameters, instead of
     printing it on the console.
 - Update test48 with new etc/services (Fix by Ben Gras <ben@minix3.org)
     get getservbyport() out of the inner loop

Change-Id: Ie6ad5226fa2621ff9f0dee8782ea48f9443d2091
2014-07-28 17:05:06 +02:00

87 lines
3.5 KiB
ArmAsm

/*-
* Copyright (c) 2012 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas of 3am Software Foundry.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <machine/asm.h>
RCSID("$NetBSD: strlen_neon.S,v 1.3 2012/12/28 05:15:08 matt Exp $")
.text
ENTRY(strlen)
mov ip, r0 /* we use r0 for return value */
ands r1, r0, #15 /* verify qword alignment */
neg r0, r1 /* subtract misalignment from count */
veor q2, q2, q2 /* clear mask */
mov r3, #7 /* NBBY - 1 */
vdup.32 q3, r3 /* dup throughout q3 */
movw r3, #0x0404 /* magic since there are 4 bytes per U32 */
orr r3, r3, lsl #16 /* copy to upper 16 bits */
beq .Lmain_loop
veor q0, q0, q0 /* clear q0 */
vmvn q2, q2 /* set all 16 bytes of mask to all 1s */
bic ip, ip, #15 /* qword align string address */
lsl r1, r1, #3 /* convert to bits */
cmp r1, #64
rsbgt r1, r1, #128 /* > 64? BE so we are shifting LSW right */
movgt r2, #0 /* > 64? leave MSW alone */
rsble r2, r1, #64 /* <=64? BE so we are shifting MSW right */
movle r1, #64 /* <=64? clear LSW */
vmov d0, r1, r2 /* set shifts for lower and upper halves */
vmovl.u32 q0, d0 /* 2 U32 -> 2 U64 */
vshl.u64 q2, q2, q0 /* shift */
/*
* Main loop. Load 16 bytes, do a clz,
*/
.Lmain_loop:
vld1.64 {d0, d1}, [ip:128]! /* load qword */
#ifdef __ARMEL__
vrev64.8 q0, q0 /* convert to BE for clz */
#endif
vswp d0, d1 /* swap dwords to get BE qword */
vorr q0, q0, q2 /* or "in" leading byte mask */
veor q2, q2, q2 /* clear leading byte mask */
vceq.i8 q1, q0, #0 /* test each byte for 0 */
/* Why couldn't there be a 64-bit CLZ? */
vclz.u32 q1, q1 /* count leading zeroes to find the 0 byte */
vadd.u32 q1, q1, q3 /* round up to byte bounary */
vshr.u32 q1, q1, #3 /* convert to bytes */
vmovn.u32 d0, q1 /* 4 I32 -> 4 I16 */
vmovn.u16 d0, q0 /* 4 I16 -> 4 I8 */
vmov r2, s0 /* get counts */
eors r2, r2, r3 /* xor with 0x04040404 */
addeq r0, #16 /* 0? no NULs */
beq .Lmain_loop /* get next qword */
clz ip, r2 /* count leading zeros */
mov r2, r2, lsl ip /* discard them */
mov ip, ip, lsr #3 /* divide leading zeroes by 8 */
add r0, r0, ip, lsl #2 /* multiple by 4 and add to count */
and r2, r2, #(3 << 29)
add r0, r0, r2, lsr #29
RET /* and return. */
END(strlen)