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/* $NetBSD: memset_arm.S,v 1.2 2013/01/14 19:15:13 matt Exp $ */
/*-
* 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>
#if defined(NEON)
#define STORE8 vst1.32 {d0}, [ip:64]!
#define STORE16 vst1.32 {d0-d1}, [ip:64]!
#define STORE32 vst1.32 {d0-d3}, [ip:64]!
#elif defined(VFP)
#define STORE8 vstmia ip!, {d0}
#define STORE16 vstmia ip!, {d0-d1}
#define STORE32 vstmia ip!, {d0-d3}
#elif defined(_ARM_ARCH_DWORD_OK)
#define STORE8 strd r2, [ip], #8
#define STORE16 STORE8; STORE8
#define STORE32 STORE16; STORE16
#else
#define STORE8 stmia ip!, {r2,r3}
#define STORE16 STORE8; STORE8
#define STORE32 STORE16; STORE16
#endif
/*
* memset: Sets a block of memory to the specified value
* Using NEON instructions
*
* On entry:
* r0 - dest address
* r1 - byte to write
* r2 - number of bytes to write
*
* On exit:
* r0 - dest address
*/
/* LINTSTUB: Func: void *memset(void *, int, size_t) */
ENTRY(memset)
ands r3, r1, #0xff /* We deal with bytes */
orrne r3, r3, r3, lsl #8 /* replicate to all bytes */
orrne r3, r3, r3, lsl #16 /* replicate to all bytes */
movs r1, r2 /* we need r2 & r3 */
RETc(eq) /* return if length is 0 */
mov ip, r0 /* r0 needs to stay the same */
cmp r1, #12 /* is this a small memset? *?
blt .Lbyte_by_byte /* then do it byte by byte */
/* Ok first we will dword align the address */
ands r2, ip, #7 /* grab the bottom three bits */
beq .Lmemset_dwordaligned /* The addr is dword aligned */
rsb r2, r2, #8 /* how far until dword aligned? */
sub r1, r1, r2 /* subtract it from remaining length */
mov r2, r3 /* duplicate fill value */
tst ip, #1 /* halfword aligned? */
strneb r3, [ip], #1 /* no, write a byte */
tst ip, #2 /* word aligned? */
strneh r3, [ip], #2 /* no, write a halfword */
tst ip, #4 /* dword aligned? */
strne r3, [ip], #4 /* no, write a word */
/* We are now doubleword aligned */
.Lmemset_dwordaligned:
#if defined(NEON)
vdup.8 q0, r3 /* move fill to SIMD */
vmov q1, q0 /* put fill in q1 (d2-d3) */
#elif defined(VFP)
mov r2, r3 /* duplicate fill value */
vmov d0, r2, r3 /* move to VFP */
vmov d1, r2, r3
vmov d2, r2, r3
vmov d3, r2, r3
#endif
#if 1
cmp r1, #128
blt .Lmemset_mainloop
ands r2, ip, #63 /* check for 64-byte alignment */
beq .Lmemset_mainloop
/*
* Let's align to a 64-byte boundary so that stores don't cross
* cacheline boundaries. We also know we have at least 128-bytes to
* copy so we don't have to worry about the length at the moment.
*/
rsb r2, r2, #64 /* how many bytes until 64 bytes */
sub r1, r1, r2 /* subtract from remaining length */
#if !defined(NEON) && !defined(VFP)
mov r2, r3 /* put fill back in r2 */
#endif
tst ip, #8 /* quadword aligned? */
beq 1f /* yes */
STORE8 /* no, store a dword */
1: tst ip, #16 /* octaword aligned? *?
beq 2f /* yes */
STORE16 /* no, store a quadword */
2: tst ip, #32 /* 32 word aligned? */
beq .Lmemset_mainloop /* yes */
STORE32 /* no, make 64-byte aligned */
#endif
.Lmemset_mainloop:
#if !defined(NEON) && !defined(VFP)
mov r2, r3 /* put fill back in r2 */
#endif
subs r1, r1, #64 /* subtract an initial 64 */
blt .Lmemset_lessthan_64bytes
3: STORE32 /* store first octaword */
STORE32 /* store second octaword */
RETc(eq) /* return if done */
subs r1, r1, #64 /* subtract another 64 */
bge 3b /* and do other if still >= 0 */
.Lmemset_lessthan_64bytes:
tst r1, #32 /* do we have 16 bytes left? */
beq .Lmemset_lessthan_32bytes
STORE32 /* yes, store an octaword */
bics r1, r1, #32 /* subtract 16 */
RETc(eq) /* return if length is 0 */
.Lmemset_lessthan_32bytes:
tst r1, #16 /* do we have 16 bytes left? */
beq .Lmemset_lessthan_16bytes
STORE16 /* yes, store a quadword */
bics r1, r1, #16 /* subtract 16 */
RETc(eq) /* return if length is 0 */
.Lmemset_lessthan_16bytes:
tst r1, #8 /* do we have 8 bytes left? */
beq .Lmemset_lessthan_8bytes/* no */
STORE8 /* yes, store a dword */
bics r1, r1, #8 /* subtract 8 */
RETc(eq) /* return if length is 0 */
.Lmemset_lessthan_8bytes:
tst r1, #4 /* do we have a word left? */
strne r2, [ip], #4 /* yes, so write one */
tst r1, #2 /* do we have a halfword left? */
strneh r2, [ip], #2 /* yes, so write one */
tst r1, #1 /* do we have a byte left? */
strneb r2, [ip], #1 /* yes, so write one */
RET /* return */
.Lbyte_by_byte:
subs r1, r1, #1 /* can we write a byte? */
RETc(lt) /* no, we're done */
strb r3, [ip], #1 /* yes, so do it */
b .Lbyte_by_byte /* try next byte */
END(memset)
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