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/*
 * Copyright (C) 2010 B Labs
 *
 * Author: Bahadir Balban
 */

#include <l4lib/arch/arm/asm.h>

/*
 * Atomically and destructively reads a byte. E.g.
 * byte is read and zero is written back. This is
 * useful on reading irq counts
 *
 * @r0 = byte address
 */
BEGIN_PROC(l4_atomic_dest_readb)
        mov     r1, #0
        swpb    r2, r1, [r0]
        mov     r0, r2
        mov     pc, lr
END_PROC(l4_atomic_dest_readb)