Shinichiro Nakamura / Mbed 2 deprecated StarBoardOrangeExample2

StarBoard Orange - Example application No.2 (Version 0.0.4)

Dependencies:   mbed

extlib/Semaphore.h

Committer:
shintamainjp
Date:
2010-08-13
Revision:
0:5d79cd4ac81d

File content as of revision 0:5d79cd4ac81d:

#ifndef _SEMAPHORE_H_
#define _SEMAPHORE_H_

/*
 * http://mbed.org/forum/mbed/topic/181/#comment-799
 */

class Semaphore {
public:
    Semaphore(): s(SemFree) {};

    bool take(bool block = true) {
        int oldval;
        do {
            oldval = __ldrex(&s);
        } while ((block && (oldval == SemTaken)) || (__strex(SemTaken, &s) != 0));
        if (!block) {
            __clrex();
        }
        return (oldval == SemFree);
    }

    void release() {
        s = SemFree;
    }

private:
    enum { SemFree, SemTaken };
    int s;
};

#endif