mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-14 23:30:06 +00:00
128 lines
3.7 KiB
ArmAsm
128 lines
3.7 KiB
ArmAsm
/* Optimized strchrnul implementation for PowerPC32/POWER7 using cmpb insn.
|
|
Copyright (C) 2010-2017 Free Software Foundation, Inc.
|
|
Contributed by Luis Machado <luisgpm@br.ibm.com>.
|
|
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>
|
|
|
|
/* int [r3] strchrnul (char *s [r3], int c [r4]) */
|
|
.machine power7
|
|
ENTRY (__strchrnul)
|
|
CALL_MCOUNT
|
|
dcbt 0,r3
|
|
clrrwi r8,r3,2 /* Align the address to word boundary. */
|
|
|
|
/* Replicate byte to word. */
|
|
insrwi r4,r4,8,16
|
|
insrwi r4,r4,16,0
|
|
|
|
rlwinm r6,r3,3,27,28 /* Calculate padding. */
|
|
lwz r12,0(r8) /* Load word from memory. */
|
|
li r0,0 /* Word with null chars to use
|
|
with cmpb. */
|
|
|
|
/* Now r4 has a word of c bytes and r0 has
|
|
a word of null bytes. */
|
|
|
|
cmpb r10,r12,r0 /* Compare each byte against c byte. */
|
|
cmpb r9,r12,r4 /* Compare each byte against null byte. */
|
|
|
|
/* Move the words left and right to discard the bits that are
|
|
not part of the string and bring them back as zeros. */
|
|
#ifdef __LITTLE_ENDIAN__
|
|
srw r10,r10,r6
|
|
srw r9,r9,r6
|
|
slw r10,r10,r6
|
|
slw r9,r9,r6
|
|
#else
|
|
slw r10,r10,r6
|
|
slw r9,r9,r6
|
|
srw r10,r10,r6
|
|
srw r9,r9,r6
|
|
#endif
|
|
or r5,r9,r10 /* OR the results to speed things up. */
|
|
cmpwi cr7,r5,0 /* If r5 == 0, no c or null bytes
|
|
have been found. */
|
|
bne cr7,L(done)
|
|
|
|
mtcrf 0x01,r8
|
|
|
|
/* Are we now aligned to a doubleword boundary? If so, skip to
|
|
the main loop. Otherwise, go through the alignment code. */
|
|
|
|
bt 29,L(loop)
|
|
|
|
/* Handle WORD2 of pair. */
|
|
lwzu r12,4(r8)
|
|
cmpb r10,r12,r0
|
|
cmpb r9,r12,r4
|
|
or r5,r9,r10
|
|
cmpwi cr7,r5,0
|
|
bne cr7,L(done)
|
|
b L(loop) /* We branch here (rather than falling through)
|
|
to skip the nops due to heavy alignment
|
|
of the loop below. */
|
|
|
|
.p2align 5
|
|
L(loop):
|
|
/* Load two words, compare and merge in a
|
|
single register for speed. This is an attempt
|
|
to speed up the null-checking process for bigger strings. */
|
|
lwz r12,4(r8)
|
|
lwzu r11,8(r8)
|
|
cmpb r10,r12,r0
|
|
cmpb r9,r12,r4
|
|
cmpb r6,r11,r0
|
|
cmpb r7,r11,r4
|
|
or r5,r9,r10
|
|
or r10,r6,r7
|
|
or r11,r5,r10
|
|
cmpwi cr7,r11,0
|
|
beq cr7,L(loop)
|
|
|
|
/* OK, one (or both) of the words contains a c/null byte. Check
|
|
the first word and decrement the address in case the first
|
|
word really contains a c/null byte. */
|
|
|
|
cmpwi cr6,r5,0
|
|
addi r8,r8,-4
|
|
bne cr6,L(done)
|
|
|
|
/* The c/null byte must be in the second word. Adjust the address
|
|
again and move the result of cmpb to r5 so we can calculate the
|
|
pointer. */
|
|
mr r5,r10
|
|
addi r8,r8,4
|
|
|
|
/* r5 has the output of the cmpb instruction, that is, it contains
|
|
0xff in the same position as the c/null byte in the original
|
|
word from the string. Use that to calculate the pointer. */
|
|
L(done):
|
|
#ifdef __LITTLE_ENDIAN__
|
|
addi r0,r5,-1
|
|
andc r0,r0,r5
|
|
popcntw r0,r0
|
|
#else
|
|
cntlzw r0,r5 /* Count leading zeros before the match. */
|
|
#endif
|
|
srwi r0,r0,3 /* Convert leading zeros to bytes. */
|
|
add r3,r8,r0 /* Return address of matching c/null byte. */
|
|
blr
|
|
END (__strchrnul)
|
|
weak_alias (__strchrnul,strchrnul)
|
|
libc_hidden_builtin_def (__strchrnul)
|