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/*
* Copyright (C) 2014 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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 COPYRIGHT HOLDERS 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
* COPYRIGHT OWNER 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.
*/
/*
Copyright (c) 2014, Linaro Limited
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* 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.
* Neither the name of the Linaro nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
HOLDER 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.
*/
/* Assumptions:
*
* ARMv8-a, AArch64
*/
#if !defined(STPCPY) && !defined(STRCPY)
#error "Either STPCPY or STRCPY must be defined."
#endif
#include <private/bionic_asm.h>
/* Arguments and results. */
#if defined(STPCPY)
#define dst x0
#elif defined(STRCPY)
#define dstin x0
#endif
#define src x1
/* Locals and temporaries. */
#if defined(STRCPY)
#define dst x2
#endif
#define data1 x3
#define data1_w w3
#define data2 x4
#define data2_w w4
#define has_nul1 x5
#define has_nul1_w w5
#define has_nul2 x6
#define tmp1 x7
#define tmp2 x8
#define tmp3 x9
#define tmp4 x10
#define zeroones x11
#define zeroones_w w11
#define pos x12
#define REP8_01 0x0101010101010101
#define REP8_7f 0x7f7f7f7f7f7f7f7f
#define REP8_80 0x8080808080808080
#if defined(STPCPY)
ENTRY(stpcpy)
#elif defined(STRCPY)
ENTRY(strcpy)
#endif
mov zeroones, #REP8_01
#if defined(STRCPY)
mov dst, dstin
#endif
ands tmp1, src, #15
b.ne .Lmisaligned
// NUL detection works on the principle that (X - 1) & (~X) & 0x80
// (=> (X - 1) & ~(X | 0x7f)) is non-zero iff a byte is zero, and
// can be done in parallel across the entire word.
// The inner loop deals with two Dwords at a time. This has a
// slightly higher start-up cost, but we should win quite quickly,
// especially on cores with a high number of issue slots per
// cycle, as we get much better parallelism out of the operations.
.Lloop:
ldp data1, data2, [src], #16
sub tmp1, data1, zeroones
orr tmp2, data1, #REP8_7f
bic has_nul1, tmp1, tmp2
cbnz has_nul1, .Lnul_in_data1
sub tmp3, data2, zeroones
orr tmp4, data2, #REP8_7f
bic has_nul2, tmp3, tmp4
cbnz has_nul2, .Lnul_in_data2
// No NUL in either register, copy it in a single instruction.
stp data1, data2, [dst], #16
b .Lloop
.Lnul_in_data1:
rev has_nul1, has_nul1
clz pos, has_nul1
add tmp1, pos, #0x8
tbz tmp1, #6, 1f
#if defined(STPCPY)
str data1, [dst], #7
#elif defined(STRCPY)
str data1, [dst]
#endif
ret
1:
tbz tmp1, #5, 1f
str data1_w, [dst], #4
lsr data1, data1, #32
1:
tbz tmp1, #4, 1f
strh data1_w, [dst], #2
lsr data1, data1, #16
1:
tbz tmp1, #3, 1f
strb data1_w, [dst]
#if defined(STPCPY)
ret
#endif
1:
#if defined(STPCPY)
// Back up one so that dst points to the '\0' string terminator.
sub dst, dst, #1
#endif
ret
.Lnul_in_data2:
str data1, [dst], #8
rev has_nul2, has_nul2
clz pos, has_nul2
add tmp1, pos, #0x8
tbz tmp1, #6, 1f
#if defined(STPCPY)
str data2, [dst], #7
#elif defined(STRCPY)
str data2, [dst]
#endif
ret
1:
tbz tmp1, #5, 1f
str data2_w, [dst], #4
lsr data2, data2, #32
1:
tbz tmp1, #4, 1f
strh data2_w, [dst], #2
lsr data2, data2, #16
1:
tbz tmp1, #3, 1f
strb data2_w, [dst]
#if defined(STPCPY)
ret
#endif
1:
#if defined(STPCPY)
// Back up one so that dst points to the '\0' string terminator.
sub dst, dst, #1
#endif
ret
.Lmisaligned:
tbz src, #0, 1f
ldrb data1_w, [src], #1
strb data1_w, [dst], #1
cbnz data1_w, 1f
#if defined(STPCPY)
// Back up one so that dst points to the '\0' string terminator.
sub dst, dst, #1
#endif
ret
1:
tbz src, #1, 1f
ldrb data1_w, [src], #1
strb data1_w, [dst], #1
cbz data1_w, .Ldone
ldrb data2_w, [src], #1
strb data2_w, [dst], #1
cbnz data2_w, 1f
.Ldone:
#if defined(STPCPY)
// Back up one so that dst points to the '\0' string terminator.
sub dst, dst, #1
#endif
ret
1:
tbz src, #2, 1f
ldr data1_w, [src], #4
// Check for a zero.
sub has_nul1_w, data1_w, zeroones_w
bic has_nul1_w, has_nul1_w, data1_w
ands has_nul1_w, has_nul1_w, #0x80808080
b.ne .Lnul_in_data1
str data1_w, [dst], #4
1:
tbz src, #3, .Lloop
ldr data1, [src], #8
// Check for a zero.
sub tmp1, data1, zeroones
orr tmp2, data1, #REP8_7f
bics has_nul1, tmp1, tmp2
b.ne .Lnul_in_data1
str data1, [dst], #8
b .Lloop
#if defined(STPCPY)
END(stpcpy)
#elif defined(STRCPY)
END(strcpy)
#endif
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