使用信号量实现监视器

Question

我试图找出如何使用信号量实现监视器。我写的（伪）代码看起来像这样：

# var globales
sem e=1, unlocked=0, wait[]={0}
int nw=0, waitlist[]={0}
bool mLock = true

entry(monitor):
    P(e)
    if mLock:
        nw++
        V(e)
        P(unlocked)
        nw--
    mLock = true


exit(monitor):
    mLock = false
    if (nw > 0): V(unlocked)
    else: V(e)

wait(monitor, cv):
    V(e)
    waitlist[cv] += 1
    P(wait[cv])
    waitlist[cv] -= 1
    P(e)

signal(monitor, cv):
    if waitlist[cv] > 0: V(wait[cv])

此实施是否有效？