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/* Optimized strtok implementation for PowerPC64.
Copyright (C) 2014-2015 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
<http://www.gnu.org/licenses/>. */
/* Performance gains are grabbed through following techniques:
> hashing of needle.
> hashing avoids scanning of duplicate entries in needle
across the string.
> unrolling when scanning for character in string
across hash table. */
/* Algorithm is as below:
1. A empty hash table/dictionary is created comprising of
256 ascii character set
2. When hash entry is found in needle , the hash index
is initialized to 1
3. The string is scanned until end and for every character,
its corresponding hash index is compared.
4. initial length of string (count) until first hit of
accept needle is calculated and moved.(strspn)
5. The string is again scanned until end and for every character,
its corresponding hash index is compared.(strpbrk)
6. If hash index is set to 1 for the index of string,
set it to null and set the saveptr to point to the next char.
7. Otherwise count is incremented and scanning continues
until end of string. */
#include <sysdep.h>
#ifdef USE_AS_STRTOK_R
# define FUNC_NAME __strtok_r
#else
# define FUNC_NAME strtok
#endif
EALIGN(FUNC_NAME, 4, 0)
#ifdef USE_AS_STRTOK_R
CALL_MCOUNT 3
cmpdi cr7, r3, 0 /* Is input null? */
bne cr7, L(inputnotNull)
ld r3, 0(r5) /* Load from r5 */
#else
CALL_MCOUNT 2
addis r5, r2, .LANCHOR0@toc@ha
cmpdi cr7, r3, 0 /* Is r3 NULL? */
bne cr7, L(inputnotNull)
ld r3, .LANCHOR0@toc@l(r5) /* Load from saveptr */
#endif
L(inputnotNull):
mr r7, r3
cmpdi cr7, r3, 0
beq cr7, L(returnNULL)
lbz r8, 0(r3)
cmpdi cr7, r8, 0
beq cr7, L(returnNULL)
addi r9, r1, -256 /* r9 is a hash of 256 bytes */
/*Iniatliaze hash table with Zeroes */
li r6, 0
li r8, 4
mtctr r8
mr r10, r9
.align 4
L(zerohash):
std r6, 0(r10)
std r6, 8(r10)
std r6, 16(r10)
std r6, 24(r10)
std r6, 32(r10)
std r6, 40(r10)
std r6, 48(r10)
std r6, 56(r10)
addi r10, r10, 64
bdnz L(zerohash)
lbz r10, 0(r4) /* load r10 with needle (r4) */
li r8, 1 /* r8=1, marker into hash if found in
needle */
cmpdi cr7, r10, 0 /* accept needle is NULL */
beq cr7, L(skipHashing) /* if needle is NULL, skip hashing */
.align 4 /* align section to 16 byte boundary */
L(hashing):
stbx r8, r9, r10 /* update hash with marker for the pivot of
the needle */
lbzu r10, 1(r4) /* load needle into r10 and update to next */
cmpdi cr7, r10, 0 /* if needle is has reached NULL, continue */
bne cr7, L(hashing) /* loop to hash the needle */
L(skipHashing):
b L(beginScan)
.align 4 /* align section to 16 byte boundary */
L(scanUnroll):
lbzx r8, r9, r8 /* load r8 with hash value at index */
cmpwi cr7, r8, 0 /* check the hash value */
beq cr7, L(ret1stIndex) /* we have hit accept needle */
lbz r8, 1(r7) /* load string[1] into r8 */
lbzx r8, r9, r8 /* load r8 with hash value at index */
cmpwi cr7, r8, 0 /* check the hash value */
beq cr7, L(ret2ndIndex) /* we have hit accept needle */
lbz r8, 2(r7) /* load string[1] into r8 */
lbzx r8, r9, r8 /* load r8 with hash value at index */
cmpwi cr7, r8, 0 /* check the hash value */
beq cr7, L(ret3rdIndex) /* we have hit accept needle */
lbz r8, 3(r7) /* load string[1] into r8 */
addi r7, r7, 4
lbzx r8, r9, r8 /* load r8 with hash value at index */
cmpwi cr7, r8, 0 /* check the hash value */
beq cr7,L(ret4thIndex) /* we have hit accept needle */
L(beginScan):
lbz r8, 0(r7) /* load string[0] into r8 */
addi r6, r7, 1
addi r11, r7, 2
addi r4, r7, 3
cmpdi cr7, r8, 0 /* check if its null */
bne cr7, L(scanUnroll) /* continue scanning */
L(ret1stIndex):
mr r3, r7
b L(next)
L(ret2ndIndex):
mr r3, r6
b L(next)
L(ret3rdIndex):
mr r3, r11
b L(next)
L(ret4thIndex):
mr r3, r4
L(next):
mr r7, r3
lbz r8, 0(r7)
cmpdi cr7, r8, 0
beq cr7, L(returnNULL)
li r8, 1
li r10, 0 /* load counter = 0 */
stbx r8, r9, r10 /* update hash for NULL */
b L(mainloop)
L(unroll):
lbz r8, 1(r7) /* load string[1] into r8 */
lbzx r8, r9, r8 /* load r8 with hash value at index */
cmpwi r7, r8, 1 /* check the hash */
beq cr7, L(foundat1st) /* we have hit accept needle */
lbz r8, 2(r7)
lbzx r8, r9, r8
cmpwi cr7, r8, 1
beq cr7, L(foundat2nd)
lbz r8, 3(r7)
addi r7, r7, 4
lbzx r8, r9, r8
cmpwi cr7, r8, 1
beq cr7, L(foundat3rd)
L(mainloop):
lbz r8, 0(r7)
addi r6, r7, 1
addi r11, r7, 2
addi r4, r7, 3
lbzx r8, r9, r8
cmpwi cr7, r8, 1
bne cr7, L(unroll) /* continue scanning */
b L(found)
L(foundat1st):
mr r7, r6
b L(found)
L(foundat2nd):
mr r7, r11
b L(found)
L(foundat3rd):
mr r7, r4
L(found):
lbz r8, 0(r7)
cmpdi cr7, r8, 0
beq cr7, L(end)
li r10, 0
stb r10, 0(r7) /* Terminate string */
addi r7, r7, 1 /* Store the pointer to the next char */
L(end):
#ifdef USE_AS_STRTOK_R
std r7, 0(r5) /* Update saveptr */
#else
std r7, .LANCHOR0@toc@l(r5)
#endif
blr /* done */
L(returnNULL):
#ifndef USE_AS_STRTOK_R
li r7, 0
#endif
li r3, 0 /* return NULL */
b L(end)
END(FUNC_NAME)
#ifdef USE_AS_STRTOK_R
libc_hidden_builtin_def (strtok_r)
#else
.section ".bss"
.align 3
.set .LANCHOR0,. + 0
.type olds, @object
.size olds, 8
olds:
.zero 8
libc_hidden_builtin_def (strtok)
#endif
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