/*
* Copyright (c) 2017 Imagination Technologies.
*
* 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 Imagination Technologies 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
* 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.
*/
#ifdef __ANDROID__
# include <private/bionic_asm.h>
#elif _LIBC
# include <sysdep.h>
# include <regdef.h>
# include <sys/asm.h>
#elif _COMPILING_NEWLIB
# include "machine/asm.h"
# include "machine/regdef.h"
#else
# include <regdef.h>
# include <sys/asm.h>
#endif
#if __mips64
# define NSIZE 8
# define LW ld
# define EXT dext
# define SRL dsrl
# define SLL dsll
# define SUBU dsubu
#else
# define NSIZE 4
# define LW lw
# define EXT ext
# define SRL srl
# define SLL sll
# define SUBU subu
#endif
/* Technically strcmp should not read past the end of the strings being
compared. We will read a full word that may contain excess bits beyond
the NULL string terminator but unless ENABLE_READAHEAD is set, we will not
read the next word after the end of string. Setting ENABLE_READAHEAD will
improve performance but is technically illegal based on the definition of
strcmp. */
#ifdef ENABLE_READAHEAD
# define DELAY_READ
#else
# define DELAY_READ nop
#endif
/* Testing on a little endian machine showed using CLZ was a
performance loss, so we are not turning it on by default. */
#if defined(ENABLE_CLZ) && (__mips_isa_rev > 1)
# define USE_CLZ
#endif
/* Some asm.h files do not have the L macro definition. */
#ifndef L
# if _MIPS_SIM == _ABIO32
# define L(label) $L ## label
# else
# define L(label) .L ## label
# endif
#endif
/* Some asm.h files do not have the PTR_ADDIU macro definition. */
#ifndef PTR_ADDIU
# if _MIPS_SIM == _ABIO32
# define PTR_ADDIU addiu
# else
# define PTR_ADDIU daddiu
# endif
#endif
/* It might seem better to do the 'beq' instruction between the two 'lbu'
instructions so that the nop is not needed but testing showed that this
code is actually faster (based on glibc strcmp test). */
#define BYTECMP01(OFFSET) \
lbu $v0, OFFSET($a0); \
lbu $v1, OFFSET($a1); \
beq $v0, $zero, L(bexit01); \
nop; \
bne $v0, $v1, L(bexit01)
#define BYTECMP89(OFFSET) \
lbu $t8, OFFSET($a0); \
lbu $t9, OFFSET($a1); \
beq $t8, $zero, L(bexit89); \
nop; \
bne $t8, $t9, L(bexit89)
/* Allow the routine to be named something else if desired. */
#ifndef STRCMP_NAME
# define STRCMP_NAME strcmp
#endif
#ifdef __ANDROID__
LEAF(STRCMP_NAME, 0)
#else
LEAF(STRCMP_NAME)
#endif
.set nomips16
.set noreorder
andi $t1, $a1, (NSIZE - 1)
beqz $t1, L(exitalign)
or $t0, $zero, NSIZE
SUBU $t1, $t0, $t1 #process (NSIZE - 1) bytes at max
L(alignloop): #do by bytes until a1 aligned
BYTECMP01(0)
SUBU $t1, $t1, 0x1
PTR_ADDIU $a0, $a0, 0x1
bnez $t1, L(alignloop)
PTR_ADDIU $a1, $a1, 0x1
L(exitalign):
/* string a1 is NSIZE byte aligned at this point. */
lui $t8, 0x0101
ori $t8, 0x0101
lui $t9, 0x7f7f
ori $t9, 0x7f7f
#if __mips64
dsll $t1, $t8, 32
or $t8, $t1
dsll $t1, $t9, 32
or $t9, $t1
#endif
andi $t2, $a0, (NSIZE - 1) #check if a0 aligned
SUBU $t3, $t0, $t2 #t3 will be used as shifter
bnez $t2, L(uloopenter)
SUBU $a2, $a0, $t2 #bring back a0 to aligned position
#define STRCMPW(OFFSET) \
LW $v0, OFFSET($a0); \
LW $v1, OFFSET($a1); \
SUBU $t0, $v0, $t8; \
bne $v0, $v1, L(worddiff); \
nor $t1, $v0, $t9; \
and $t0, $t0, $t1; \
bne $t0, $zero, L(returnzero);\
L(wordloop):
STRCMPW(0 * NSIZE)
DELAY_READ
STRCMPW(1 * NSIZE)
DELAY_READ
STRCMPW(2 * NSIZE)
DELAY_READ
STRCMPW(3 * NSIZE)
DELAY_READ
STRCMPW(4 * NSIZE)
DELAY_READ
STRCMPW(5 * NSIZE)
DELAY_READ
STRCMPW(6 * NSIZE)
DELAY_READ
STRCMPW(7 * NSIZE)
PTR_ADDIU $a0, $a0, (8 * NSIZE)
b L(wordloop)
PTR_ADDIU $a1, $a1, (8 * NSIZE)
#define USTRCMPW(OFFSET) \
LW $v1, OFFSET($a1); \
SUBU $t0, $v0, $t8; \
nor $t1, $v0, $t9; \
and $t0, $t0, $t1; \
bne $t0, $zero, L(worddiff); \
SRL $v0, $t2; \
LW $a3, (OFFSET + NSIZE)($a2); \
SUBU $t0, $v1, $t8; \
SLL $t1, $a3, $t3; \
or $v0, $v0, $t1; \
bne $v0, $v1, L(worddiff); \
nor $t1, $v1, $t9; \
and $t0, $t0, $t1; \
bne $t0, $zero, L(returnzero); \
move $v0, $a3;\
L(uloopenter):
LW $v0, 0($a2)
SLL $t2, 3 #multiply by 8
SLL $t3, 3 #multiply by 8
li $a3, -1 #all 1s
SRL $a3, $t3
or $v0, $a3 #replace with all 1s if zeros in unintented read
L(uwordloop):
USTRCMPW(0 * NSIZE)
USTRCMPW(1 * NSIZE)
USTRCMPW(2 * NSIZE)
USTRCMPW(3 * NSIZE)
USTRCMPW(4 * NSIZE)
USTRCMPW(5 * NSIZE)
USTRCMPW(6 * NSIZE)
USTRCMPW(7 * NSIZE)
PTR_ADDIU $a2, $a2, (8 * NSIZE)
b L(uwordloop)
PTR_ADDIU $a1, $a1, (8 * NSIZE)
L(returnzero):
j $ra
move $v0, $zero
#if __mips_isa_rev > 1
#define EXT_COMPARE01(POS) \
EXT $t0, $v0, POS, 8; \
beq $t0, $zero, L(wexit01); \
EXT $t1, $v1, POS, 8; \
bne $t0, $t1, L(wexit01)
#define EXT_COMPARE89(POS) \
EXT $t8, $v0, POS, 8; \
beq $t8, $zero, L(wexit89); \
EXT $t9, $v1, POS, 8; \
bne $t8, $t9, L(wexit89)
#else
#define EXT_COMPARE01(POS) \
SRL $t0, $v0, POS; \
SRL $t1, $v1, POS; \
andi $t0, $t0, 0xff; \
beq $t0, $zero, L(wexit01); \
andi $t1, $t1, 0xff; \
bne $t0, $t1, L(wexit01)
#define EXT_COMPARE89(POS) \
SRL $t8, $v0, POS; \
SRL $t9, $v1, POS; \
andi $t8, $t8, 0xff; \
beq $t8, $zero, L(wexit89); \
andi $t9, $t9, 0xff; \
bne $t8, $t9, L(wexit89)
#endif
L(worddiff):
#ifdef USE_CLZ
SUBU $t0, $v0, $t8
nor $t1, $v0, $t9
and $t1, $t0, $t1
xor $t0, $v0, $v1
or $t0, $t0, $t1
# if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
wsbh $t0, $t0
rotr $t0, $t0, 16
# endif
clz $t1, $t0
and $t1, 0xf8
# if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
neg $t1
addu $t1, 24
# endif
rotrv $v0, $v0, $t1
rotrv $v1, $v1, $t1
and $v0, $v0, 0xff
and $v1, $v1, 0xff
j $ra
SUBU $v0, $v0, $v1
#else /* USE_CLZ */
# if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
andi $t0, $v0, 0xff
beq $t0, $zero, L(wexit01)
andi $t1, $v1, 0xff
bne $t0, $t1, L(wexit01)
EXT_COMPARE89(8)
EXT_COMPARE01(16)
#ifndef __mips64
SRL $t8, $v0, 24
SRL $t9, $v1, 24
#else
EXT_COMPARE89(24)
EXT_COMPARE01(32)
EXT_COMPARE89(40)
EXT_COMPARE01(48)
SRL $t8, $v0, 56
SRL $t9, $v1, 56
#endif
# else /* __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ */
#ifdef __mips64
SRL $t0, $v0, 56
beq $t0, $zero, L(wexit01)
SRL $t1, $v1, 56
bne $t0, $t1, L(wexit01)
EXT_COMPARE89(48)
EXT_COMPARE01(40)
EXT_COMPARE89(32)
EXT_COMPARE01(24)
#else
SRL $t0, $v0, 24
beq $t0, $zero, L(wexit01)
SRL $t1, $v1, 24
bne $t0, $t1, L(wexit01)
#endif
EXT_COMPARE89(16)
EXT_COMPARE01(8)
andi $t8, $v0, 0xff
andi $t9, $v1, 0xff
# endif /* __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ */
L(wexit89):
j $ra
SUBU $v0, $t8, $t9
L(wexit01):
j $ra
SUBU $v0, $t0, $t1
#endif /* USE_CLZ */
L(byteloop):
BYTECMP01(0)
BYTECMP89(1)
BYTECMP01(2)
BYTECMP89(3)
BYTECMP01(4)
BYTECMP89(5)
BYTECMP01(6)
BYTECMP89(7)
PTR_ADDIU $a0, $a0, 8
b L(byteloop)
PTR_ADDIU $a1, $a1, 8
L(bexit01):
j $ra
SUBU $v0, $v0, $v1
L(bexit89):
j $ra
SUBU $v0, $t8, $t9
.set at
.set reorder
END(STRCMP_NAME)
#ifndef __ANDROID__
# ifdef _LIBC
libc_hidden_builtin_def (STRCMP_NAME)
# endif
#endif