Subversion Repositories c0or1k

/*

 * Copyright (C) 2009 Bahadir Balban

 */

#include 

#include 

/*

 * These use the same lock word for both being granted

 * exclusive access to the word, and for storing lock values.

 */

BEGIN_PROC(__l4_mutex_lock)

        mov     r2, #-2

1:

        swp     r1, r2, [r0]

        cmp     r1, r2

        beq     1b

        @ Grabbed the lock,

        add     r1, r1, #1              @ now increment its value

        str     r1, [r0]                @ Store and finish

        cmp     r1, #L4_MUTEX_LOCKED    @ Have we locked it?

        moveq   r0, #L4_MUTEX_SUCCESS

        movne   r0, #L4_MUTEX_CONTENDED

        mov     pc, lr

END_PROC(__l4_mutex_lock)

BEGIN_PROC(__l4_mutex_unlock)

        mov     r2, #-2

        mov     r1, #L4_MUTEX_UNLOCKED

1:

        swp     r3, r2, [r0]

        cmp     r3, r2

        beq     1b

        @ Grabbed the lock

        str     r1, [r0]                @ Now store unlocked value and finish

        mov     r0, r3                  @ Get the value of contenders

        mov     pc, lr

END_PROC(__l4_mutex_unlock)