linux/arch/xtensa/lib/strnlen_user.S
Chris Zankel 173d668138 [PATCH] xtensa: remove extra header files
The Xtensa port contained many header files that were never needed.  This
rather lengthy patch removes all those files.  Unfortunately, there were
many dependencies that needed to be updated, so this patch touches quite a
few source files.

Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-10 09:55:39 -08:00

148 lines
3.8 KiB
ArmAsm

/*
* arch/xtensa/lib/strnlen_user.S
*
* This file is subject to the terms and conditions of the GNU General
* Public License. See the file "COPYING" in the main directory of
* this archive for more details.
*
* Returns strnlen, including trailing zero terminator.
* Zero indicates error.
*
* Copyright (C) 2002 Tensilica Inc.
*/
#include <asm/variant/core.h>
/* Load or store instructions that may cause exceptions use the EX macro. */
#define EX(insn,reg1,reg2,offset,handler) \
9: insn reg1, reg2, offset; \
.section __ex_table, "a"; \
.word 9b, handler; \
.previous
/*
* size_t __strnlen_user(const char *s, size_t len)
*/
.text
.begin literal
.align 4
.Lmask0:
.byte 0xff, 0x00, 0x00, 0x00
.Lmask1:
.byte 0x00, 0xff, 0x00, 0x00
.Lmask2:
.byte 0x00, 0x00, 0xff, 0x00
.Lmask3:
.byte 0x00, 0x00, 0x00, 0xff
.end literal
# Register use:
# a2/ src
# a3/ len
# a4/ tmp
# a5/ mask0
# a6/ mask1
# a7/ mask2
# a8/ mask3
# a9/ tmp
# a10/ tmp
.align 4
.global __strnlen_user
.type __strnlen_user,@function
__strnlen_user:
entry sp, 16 # minimal stack frame
# a2/ s, a3/ len
addi a4, a2, -4 # because we overincrement at the end;
# we compensate with load offsets of 4
l32r a5, .Lmask0 # mask for byte 0
l32r a6, .Lmask1 # mask for byte 1
l32r a7, .Lmask2 # mask for byte 2
l32r a8, .Lmask3 # mask for byte 3
bbsi.l a2, 0, .L1mod2 # if only 8-bit aligned
bbsi.l a2, 1, .L2mod4 # if only 16-bit aligned
/*
* String is word-aligned.
*/
.Laligned:
srli a10, a3, 2 # number of loop iterations with 4B per loop
#if XCHAL_HAVE_LOOPS
loopnez a10, .Ldone
#else
beqz a10, .Ldone
slli a10, a10, 2
add a10, a10, a4 # a10 = end of last 4B chunk
#endif /* XCHAL_HAVE_LOOPS */
.Loop:
EX(l32i, a9, a4, 4, lenfixup) # get next word of string
addi a4, a4, 4 # advance string pointer
bnone a9, a5, .Lz0 # if byte 0 is zero
bnone a9, a6, .Lz1 # if byte 1 is zero
bnone a9, a7, .Lz2 # if byte 2 is zero
bnone a9, a8, .Lz3 # if byte 3 is zero
#if !XCHAL_HAVE_LOOPS
blt a4, a10, .Loop
#endif
.Ldone:
EX(l32i, a9, a4, 4, lenfixup) # load 4 bytes for remaining checks
bbci.l a3, 1, .L100
# check two more bytes (bytes 0, 1 of word)
addi a4, a4, 2 # advance string pointer
bnone a9, a5, .Lz0 # if byte 0 is zero
bnone a9, a6, .Lz1 # if byte 1 is zero
.L100:
bbci.l a3, 0, .L101
# check one more byte (byte 2 of word)
# Actually, we don't need to check. Zero or nonzero, we'll add one.
# Do not add an extra one for the NULL terminator since we have
# exhausted the original len parameter.
addi a4, a4, 1 # advance string pointer
.L101:
sub a2, a4, a2 # compute length
retw
# NOTE that in several places below, we point to the byte just after
# the zero byte in order to include the NULL terminator in the count.
.Lz3: # byte 3 is zero
addi a4, a4, 3 # point to zero byte
.Lz0: # byte 0 is zero
addi a4, a4, 1 # point just beyond zero byte
sub a2, a4, a2 # subtract to get length
retw
.Lz1: # byte 1 is zero
addi a4, a4, 1+1 # point just beyond zero byte
sub a2, a4, a2 # subtract to get length
retw
.Lz2: # byte 2 is zero
addi a4, a4, 2+1 # point just beyond zero byte
sub a2, a4, a2 # subtract to get length
retw
.L1mod2: # address is odd
EX(l8ui, a9, a4, 4, lenfixup) # get byte 0
addi a4, a4, 1 # advance string pointer
beqz a9, .Lz3 # if byte 0 is zero
bbci.l a4, 1, .Laligned # if string pointer is now word-aligned
.L2mod4: # address is 2 mod 4
addi a4, a4, 2 # advance ptr for aligned access
EX(l32i, a9, a4, 0, lenfixup) # get word with first two bytes of string
bnone a9, a7, .Lz2 # if byte 2 (of word, not string) is zero
bany a9, a8, .Laligned # if byte 3 (of word, not string) is nonzero
# byte 3 is zero
addi a4, a4, 3+1 # point just beyond zero byte
sub a2, a4, a2 # subtract to get length
retw
.section .fixup, "ax"
.align 4
lenfixup:
movi a2, 0
retw