From f3e03796652b792bb3fd5d3d25b687b9a7f14633 Mon Sep 17 00:00:00 2001 From: Alex AUVOLAT Date: Fri, 18 May 2012 11:25:25 +0200 Subject: A bit of a change in the directory layout. --- src/kernel/lib/sched.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 src/kernel/lib/sched.c (limited to 'src/kernel/lib/sched.c') diff --git a/src/kernel/lib/sched.c b/src/kernel/lib/sched.c new file mode 100644 index 0000000..29ea8a8 --- /dev/null +++ b/src/kernel/lib/sched.c @@ -0,0 +1,26 @@ +#include + +/* Internal use only. This function is atomic, meaning it cannot be interrupted by a system task switch. */ +static uint32_t atomic_exchange(uint32_t* ptr, uint32_t newval) { + uint32_t r; + asm volatile("xchg (%%ecx), %%eax" : "=a"(r) : "c"(ptr), "a"(newval)); + return r; +} + +int mutex_lock(uint32_t* mutex) { + while (atomic_exchange(mutex, MUTEX_LOCKED) == MUTEX_LOCKED) { + schedule(); + } + return 0; +} + +int mutex_lockE(uint32_t* mutex) { + if (atomic_exchange(mutex, MUTEX_LOCKED) == MUTEX_LOCKED) { + return 0; + } + return 1; +} + +void mutex_unlock(uint32_t* mutex) { + *mutex = MUTEX_UNLOCKED; +} -- cgit v1.2.3