mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-29 08:11:08 +00:00
312ded0d63
`#ifndef STPCPY` is incorrect for checking if `STRCPY` is already defined. It doesn't end up mattering as the whole check is guarded by `#if IS_IN (libc)` but is incorrect none the less.
157 lines
5.0 KiB
ArmAsm
157 lines
5.0 KiB
ArmAsm
/* strcpy/stpcpy implementation for x86-64.
|
|
Copyright (C) 2002-2022 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
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#include <isa-level.h>
|
|
|
|
#if ISA_SHOULD_BUILD (1)
|
|
|
|
# include <sysdep.h>
|
|
|
|
# ifndef STRCPY
|
|
# define STRCPY __strcpy_sse2
|
|
# endif
|
|
|
|
.text
|
|
ENTRY (STRCPY)
|
|
movq %rsi, %rcx /* Source register. */
|
|
andl $7, %ecx /* mask alignment bits */
|
|
movq %rdi, %rdx /* Duplicate destination pointer. */
|
|
|
|
jz 5f /* aligned => start loop */
|
|
|
|
neg %ecx /* We need to align to 8 bytes. */
|
|
addl $8,%ecx
|
|
/* Search the first bytes directly. */
|
|
0:
|
|
movb (%rsi), %al /* Fetch a byte */
|
|
testb %al, %al /* Is it NUL? */
|
|
movb %al, (%rdx) /* Store it */
|
|
jz 4f /* If it was NUL, done! */
|
|
incq %rsi
|
|
incq %rdx
|
|
decl %ecx
|
|
jnz 0b
|
|
|
|
5:
|
|
movq $0xfefefefefefefeff,%r8
|
|
|
|
/* Now the sources is aligned. Unfortunatly we cannot force
|
|
to have both source and destination aligned, so ignore the
|
|
alignment of the destination. */
|
|
.p2align 4
|
|
1:
|
|
/* 1st unroll. */
|
|
movq (%rsi), %rax /* Read double word (8 bytes). */
|
|
addq $8, %rsi /* Adjust pointer for next word. */
|
|
movq %rax, %r9 /* Save a copy for NUL finding. */
|
|
addq %r8, %r9 /* add the magic value to the word. We get
|
|
carry bits reported for each byte which
|
|
is *not* 0 */
|
|
jnc 3f /* highest byte is NUL => return pointer */
|
|
xorq %rax, %r9 /* (word+magic)^word */
|
|
orq %r8, %r9 /* set all non-carry bits */
|
|
incq %r9 /* add 1: if one carry bit was *not* set
|
|
the addition will not result in 0. */
|
|
|
|
jnz 3f /* found NUL => return pointer */
|
|
|
|
movq %rax, (%rdx) /* Write value to destination. */
|
|
addq $8, %rdx /* Adjust pointer. */
|
|
|
|
/* 2nd unroll. */
|
|
movq (%rsi), %rax /* Read double word (8 bytes). */
|
|
addq $8, %rsi /* Adjust pointer for next word. */
|
|
movq %rax, %r9 /* Save a copy for NUL finding. */
|
|
addq %r8, %r9 /* add the magic value to the word. We get
|
|
carry bits reported for each byte which
|
|
is *not* 0 */
|
|
jnc 3f /* highest byte is NUL => return pointer */
|
|
xorq %rax, %r9 /* (word+magic)^word */
|
|
orq %r8, %r9 /* set all non-carry bits */
|
|
incq %r9 /* add 1: if one carry bit was *not* set
|
|
the addition will not result in 0. */
|
|
|
|
jnz 3f /* found NUL => return pointer */
|
|
|
|
movq %rax, (%rdx) /* Write value to destination. */
|
|
addq $8, %rdx /* Adjust pointer. */
|
|
|
|
/* 3rd unroll. */
|
|
movq (%rsi), %rax /* Read double word (8 bytes). */
|
|
addq $8, %rsi /* Adjust pointer for next word. */
|
|
movq %rax, %r9 /* Save a copy for NUL finding. */
|
|
addq %r8, %r9 /* add the magic value to the word. We get
|
|
carry bits reported for each byte which
|
|
is *not* 0 */
|
|
jnc 3f /* highest byte is NUL => return pointer */
|
|
xorq %rax, %r9 /* (word+magic)^word */
|
|
orq %r8, %r9 /* set all non-carry bits */
|
|
incq %r9 /* add 1: if one carry bit was *not* set
|
|
the addition will not result in 0. */
|
|
|
|
jnz 3f /* found NUL => return pointer */
|
|
|
|
movq %rax, (%rdx) /* Write value to destination. */
|
|
addq $8, %rdx /* Adjust pointer. */
|
|
|
|
/* 4th unroll. */
|
|
movq (%rsi), %rax /* Read double word (8 bytes). */
|
|
addq $8, %rsi /* Adjust pointer for next word. */
|
|
movq %rax, %r9 /* Save a copy for NUL finding. */
|
|
addq %r8, %r9 /* add the magic value to the word. We get
|
|
carry bits reported for each byte which
|
|
is *not* 0 */
|
|
jnc 3f /* highest byte is NUL => return pointer */
|
|
xorq %rax, %r9 /* (word+magic)^word */
|
|
orq %r8, %r9 /* set all non-carry bits */
|
|
incq %r9 /* add 1: if one carry bit was *not* set
|
|
the addition will not result in 0. */
|
|
|
|
jnz 3f /* found NUL => return pointer */
|
|
|
|
movq %rax, (%rdx) /* Write value to destination. */
|
|
addq $8, %rdx /* Adjust pointer. */
|
|
jmp 1b /* Next iteration. */
|
|
|
|
/* Do the last few bytes. %rax contains the value to write.
|
|
The loop is unrolled twice. */
|
|
.p2align 4
|
|
3:
|
|
/* Note that stpcpy needs to return with the value of the NUL
|
|
byte. */
|
|
movb %al, (%rdx) /* 1st byte. */
|
|
testb %al, %al /* Is it NUL. */
|
|
jz 4f /* yes, finish. */
|
|
incq %rdx /* Increment destination. */
|
|
movb %ah, (%rdx) /* 2nd byte. */
|
|
testb %ah, %ah /* Is it NUL?. */
|
|
jz 4f /* yes, finish. */
|
|
incq %rdx /* Increment destination. */
|
|
shrq $16, %rax /* Shift... */
|
|
jmp 3b /* and look at next two bytes in %rax. */
|
|
|
|
4:
|
|
# ifdef USE_AS_STPCPY
|
|
movq %rdx, %rax /* Destination is return value. */
|
|
# else
|
|
movq %rdi, %rax /* Source is return value. */
|
|
# endif
|
|
retq
|
|
END (STRCPY)
|
|
#endif
|