arch/arm/lib/clearbit.S


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26

/*
 * linux/arch/arm/lib/clearbit.S
 *
 * Copyright (C) 1995-1996 Russell King
 */

#include <linux/linkage.h>
#include <asm/assembler.h>
                .text

@ Purpose  : Function to clear a bit
@ Prototype: int clear_bit(int bit,int *addr)

ENTRY(clear_bit)
		and	r2, r0, #7
		mov	r3, #1
		mov	r3, r3, lsl r2
		SAVEIRQS(ip)
		DISABLEIRQS(ip)
		ldrb	r2, [r1, r0, lsr #3]
		bic	r2, r2, r3
		strb	r2, [r1, r0, lsr #3]
		RESTOREIRQS(ip)
		RETINSTR(mov,pc,lr)