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/* $Id: strnlen_user.S,v 1.2 1999/11/19 20:35:21 ralf Exp $
*
* 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.
*
* Copyright (c) 1996, 1998, 1999 by Ralf Baechle
* Copyright (c) 1999 Silicon Graphics, Inc.
*/
#include <asm/asm.h>
#include <asm/offset.h>
#include <asm/regdef.h>
#include <asm/sgidefs.h>
#define EX(insn,reg,addr,handler) \
9: insn reg, addr; \
.section __ex_table,"a"; \
PTR 9b, handler; \
.previous
/*
* Return the size of a string (including the ending 0)
*
* Return 0 for error, len of string but at max a1 otherwise
*
* Note: for performance reasons we deliberately accept that a user may
* make strlen_user and strnlen_user access the first few KSEG0
* bytes. There's nothing secret there ...
*/
LEAF(__strnlen_user_asm)
lw v0, THREAD_CURDS($28) # pointer ok?
and v0, a0
bltz v0, fault
EXPORT(__strnlen_user_nocheck_asm)
.type __strnlen_user_nocheck_asm,@function
move v0, a0
addu a1, a0 # stop pointer
.set noreorder
1: beq v0, a1, 1f # limit reached?
addiu v0, 1
.set reorder
EX(lb, t0, -1(v0), fault)
bnez t0, 1b
1: subu v0, a0
jr ra
END(__strnlen_user_asm)
.section __ex_table,"a"
PTR 1b, fault
.previous
fault: move v0, zero
jr ra
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