From 0b44a0315b47dd8eced9f3b7f31580cf14bbfc01 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Sat, 12 Feb 2011 00:22:29 -0500 Subject: initial check-in, version 0.5.0 --- src/thread/pthread_barrier_wait.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) create mode 100644 src/thread/pthread_barrier_wait.c (limited to 'src/thread/pthread_barrier_wait.c') diff --git a/src/thread/pthread_barrier_wait.c b/src/thread/pthread_barrier_wait.c new file mode 100644 index 00000000..02c252ad --- /dev/null +++ b/src/thread/pthread_barrier_wait.c @@ -0,0 +1,31 @@ +#include "pthread_impl.h" + +int pthread_barrier_wait(pthread_barrier_t *b) +{ + int cur; + + /* Trivial case: count was set at 1 */ + if (!b->__limit) return PTHREAD_BARRIER_SERIAL_THREAD; + + /* Wait for anyone still suspended at previous use of barrier */ + while ((cur=b->__left)) + __wait(&b->__left, &b->__waiters, cur, 0); + + /* If we are the last to reach barrier, reset it and wake others */ + if (a_fetch_add(&b->__count, 1) == b->__limit) { + b->__left = b->__limit; + b->__count = 0; + __wake(&b->__count, -1, 0); + return PTHREAD_BARRIER_SERIAL_THREAD; + } + + /* Wait for our peers to reach the barrier */ + while ((cur=b->__count)) + __wait(&b->__count, 0, cur, 0); + + /* If we're the last to wake up and barrier is awaiting reuse */ + if (a_fetch_add(&b->__left, -1) == 1 && b->__waiters) + __wake(&b->__left, -1, 0); + + return 0; +} -- cgit v1.2.1