linux/arch/mips/lib/strlen_user.S
Steven J. Hill b1bac37345 MIPS: microMIPS: Optimise 'strlen' core library function.
Optimise 'strlen' to use microMIPS instructions and/or optimisations
for binary size reduction. When the microMIPS ISA is not being used,
the library function compiles to the original binary code.

Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
2013-05-09 17:55:19 +02:00

41 lines
915 B
ArmAsm

/*
* 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, 2004 by Ralf Baechle
* Copyright (C) 1999 Silicon Graphics, Inc.
* Copyright (C) 2011 MIPS Technologies, Inc.
*/
#include <asm/asm.h>
#include <asm/asm-offsets.h>
#include <asm/regdef.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
*/
LEAF(__strlen_user_asm)
LONG_L v0, TI_ADDR_LIMIT($28) # pointer ok?
and v0, a0
bnez v0, .Lfault
FEXPORT(__strlen_user_nocheck_asm)
move v0, a0
1: EX(lbu, v1, (v0), .Lfault)
PTR_ADDIU v0, 1
bnez v1, 1b
PTR_SUBU v0, a0
jr ra
END(__strlen_user_asm)
.Lfault: move v0, zero
jr ra