linux-stable/arch/xtensa/lib/strncpy_user.S
Chris Zankel 367b8112fe xtensa: move headers files to arch/xtensa/include
Move all header files for xtensa to arch/xtensa/include and platform and
variant header files to the appropriate arch/xtensa/platforms/ and
arch/xtensa/variants/ directories.

Moving the files gets also rid of all uses of symlinks in the Makefile.

This has been completed already for the majority of the architectures
and xtensa is one out of six missing.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Chris Zankel <chris@zankel.net>
2008-11-06 10:25:09 -08:00

225 lines
5.6 KiB
ArmAsm

/*
* arch/xtensa/lib/strncpy_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: -EFAULT if exception before terminator, N if the entire
* buffer filled, else strlen.
*
* Copyright (C) 2002 Tensilica Inc.
*/
#include <variant/core.h>
#include <linux/errno.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
/*
* char *__strncpy_user(char *dst, const char *src, size_t len)
*/
#ifdef __XTENSA_EB__
# define MASK0 0xff000000
# define MASK1 0x00ff0000
# define MASK2 0x0000ff00
# define MASK3 0x000000ff
#else
# define MASK0 0x000000ff
# define MASK1 0x0000ff00
# define MASK2 0x00ff0000
# define MASK3 0xff000000
#endif
# Register use
# a0/ return address
# a1/ stack pointer
# a2/ return value
# a3/ src
# a4/ len
# a5/ mask0
# a6/ mask1
# a7/ mask2
# a8/ mask3
# a9/ tmp
# a10/ tmp
# a11/ dst
# a12/ tmp
.text
.align 4
.global __strncpy_user
.type __strncpy_user,@function
__strncpy_user:
entry sp, 16 # minimal stack frame
# a2/ dst, a3/ src, a4/ len
mov a11, a2 # leave dst in return value register
beqz a4, .Lret # if len is zero
movi a5, MASK0 # mask for byte 0
movi a6, MASK1 # mask for byte 1
movi a7, MASK2 # mask for byte 2
movi a8, MASK3 # mask for byte 3
bbsi.l a3, 0, .Lsrc1mod2 # if only 8-bit aligned
bbsi.l a3, 1, .Lsrc2mod4 # if only 16-bit aligned
.Lsrcaligned: # return here when src is word-aligned
srli a12, a4, 2 # number of loop iterations with 4B per loop
movi a9, 3
bnone a11, a9, .Laligned
j .Ldstunaligned
.Lsrc1mod2: # src address is odd
EX(l8ui, a9, a3, 0, fixup_l) # get byte 0
addi a3, a3, 1 # advance src pointer
EX(s8i, a9, a11, 0, fixup_s) # store byte 0
beqz a9, .Lret # if byte 0 is zero
addi a11, a11, 1 # advance dst pointer
addi a4, a4, -1 # decrement len
beqz a4, .Lret # if len is zero
bbci.l a3, 1, .Lsrcaligned # if src is now word-aligned
.Lsrc2mod4: # src address is 2 mod 4
EX(l8ui, a9, a3, 0, fixup_l) # get byte 0
/* 1-cycle interlock */
EX(s8i, a9, a11, 0, fixup_s) # store byte 0
beqz a9, .Lret # if byte 0 is zero
addi a11, a11, 1 # advance dst pointer
addi a4, a4, -1 # decrement len
beqz a4, .Lret # if len is zero
EX(l8ui, a9, a3, 1, fixup_l) # get byte 0
addi a3, a3, 2 # advance src pointer
EX(s8i, a9, a11, 0, fixup_s) # store byte 0
beqz a9, .Lret # if byte 0 is zero
addi a11, a11, 1 # advance dst pointer
addi a4, a4, -1 # decrement len
bnez a4, .Lsrcaligned # if len is nonzero
.Lret:
sub a2, a11, a2 # compute strlen
retw
/*
* dst is word-aligned, src is word-aligned
*/
.align 4 # 1 mod 4 alignment for LOOPNEZ
.byte 0 # (0 mod 4 alignment for LBEG)
.Laligned:
#if XCHAL_HAVE_LOOPS
loopnez a12, .Loop1done
#else
beqz a12, .Loop1done
slli a12, a12, 2
add a12, a12, a11 # a12 = end of last 4B chunck
#endif
.Loop1:
EX(l32i, a9, a3, 0, fixup_l) # get word from src
addi a3, a3, 4 # advance src 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
EX(s32i, a9, a11, 0, fixup_s) # store word to dst
bnone a9, a8, .Lz3 # if byte 3 is zero
addi a11, a11, 4 # advance dst pointer
#if !XCHAL_HAVE_LOOPS
blt a11, a12, .Loop1
#endif
.Loop1done:
bbci.l a4, 1, .L100
# copy 2 bytes
EX(l16ui, a9, a3, 0, fixup_l)
addi a3, a3, 2 # advance src pointer
#ifdef __XTENSA_EB__
bnone a9, a7, .Lz0 # if byte 2 is zero
bnone a9, a8, .Lz1 # if byte 3 is zero
#else
bnone a9, a5, .Lz0 # if byte 0 is zero
bnone a9, a6, .Lz1 # if byte 1 is zero
#endif
EX(s16i, a9, a11, 0, fixup_s)
addi a11, a11, 2 # advance dst pointer
.L100:
bbci.l a4, 0, .Lret
EX(l8ui, a9, a3, 0, fixup_l)
/* slot */
EX(s8i, a9, a11, 0, fixup_s)
beqz a9, .Lret # if byte is zero
addi a11, a11, 1-3 # advance dst ptr 1, but also cancel
# the effect of adding 3 in .Lz3 code
/* fall thru to .Lz3 and "retw" */
.Lz3: # byte 3 is zero
addi a11, a11, 3 # advance dst pointer
sub a2, a11, a2 # compute strlen
retw
.Lz0: # byte 0 is zero
#ifdef __XTENSA_EB__
movi a9, 0
#endif /* __XTENSA_EB__ */
EX(s8i, a9, a11, 0, fixup_s)
sub a2, a11, a2 # compute strlen
retw
.Lz1: # byte 1 is zero
#ifdef __XTENSA_EB__
extui a9, a9, 16, 16
#endif /* __XTENSA_EB__ */
EX(s16i, a9, a11, 0, fixup_s)
addi a11, a11, 1 # advance dst pointer
sub a2, a11, a2 # compute strlen
retw
.Lz2: # byte 2 is zero
#ifdef __XTENSA_EB__
extui a9, a9, 16, 16
#endif /* __XTENSA_EB__ */
EX(s16i, a9, a11, 0, fixup_s)
movi a9, 0
EX(s8i, a9, a11, 2, fixup_s)
addi a11, a11, 2 # advance dst pointer
sub a2, a11, a2 # compute strlen
retw
.align 4 # 1 mod 4 alignment for LOOPNEZ
.byte 0 # (0 mod 4 alignment for LBEG)
.Ldstunaligned:
/*
* for now just use byte copy loop
*/
#if XCHAL_HAVE_LOOPS
loopnez a4, .Lunalignedend
#else
beqz a4, .Lunalignedend
add a12, a11, a4 # a12 = ending address
#endif /* XCHAL_HAVE_LOOPS */
.Lnextbyte:
EX(l8ui, a9, a3, 0, fixup_l)
addi a3, a3, 1
EX(s8i, a9, a11, 0, fixup_s)
beqz a9, .Lunalignedend
addi a11, a11, 1
#if !XCHAL_HAVE_LOOPS
blt a11, a12, .Lnextbyte
#endif
.Lunalignedend:
sub a2, a11, a2 # compute strlen
retw
.section .fixup, "ax"
.align 4
/* For now, just return -EFAULT. Future implementations might
* like to clear remaining kernel space, like the fixup
* implementation in memset(). Thus, we differentiate between
* load/store fixups. */
fixup_s:
fixup_l:
movi a2, -EFAULT
retw