Shinichiro Nakamura
This is for http://mbed.org/forum/bugs-suggestions/topic/1074/
Semaphore.h@0:49c0ef6111e6, 2010-09-08 (annotated)
- Committer:
- shintamainjp
- Date:
- Wed Sep 08 12:53:38 2010 +0000
- Revision:
- 0:49c0ef6111e6
- Child:
- 1:70466efca68e
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| shintamainjp | 0:49c0ef6111e6 | 1 | #ifndef _SEMAPHORE_H_ |
| shintamainjp | 0:49c0ef6111e6 | 2 | #define _SEMAPHORE_H_ |
| shintamainjp | 0:49c0ef6111e6 | 3 | |
| shintamainjp | 0:49c0ef6111e6 | 4 | /* |
| shintamainjp | 0:49c0ef6111e6 | 5 | * http://mbed.org/forum/mbed/topic/181/#comment-799 |
| shintamainjp | 0:49c0ef6111e6 | 6 | */ |
| shintamainjp | 0:49c0ef6111e6 | 7 | |
| shintamainjp | 0:49c0ef6111e6 | 8 | class Semaphore { |
| shintamainjp | 0:49c0ef6111e6 | 9 | public: |
| shintamainjp | 0:49c0ef6111e6 | 10 | Semaphore(): s(SemFree) {} |
| shintamainjp | 0:49c0ef6111e6 | 11 | |
| shintamainjp | 0:49c0ef6111e6 | 12 | bool take(bool block = true) { |
| shintamainjp | 0:49c0ef6111e6 | 13 | int oldval; |
| shintamainjp | 0:49c0ef6111e6 | 14 | do { |
| shintamainjp | 0:49c0ef6111e6 | 15 | oldval = __ldrex(&s); |
| shintamainjp | 0:49c0ef6111e6 | 16 | } while ((block && oldval == SemTaken) || __strex(SemTaken, &s) != 0); |
| shintamainjp | 0:49c0ef6111e6 | 17 | if (!block) { |
| shintamainjp | 0:49c0ef6111e6 | 18 | __clrex(); |
| shintamainjp | 0:49c0ef6111e6 | 19 | } |
| shintamainjp | 0:49c0ef6111e6 | 20 | return (oldval == SemFree); |
| shintamainjp | 0:49c0ef6111e6 | 21 | } |
| shintamainjp | 0:49c0ef6111e6 | 22 | |
| shintamainjp | 0:49c0ef6111e6 | 23 | void release() { |
| shintamainjp | 0:49c0ef6111e6 | 24 | s = SemFree; |
| shintamainjp | 0:49c0ef6111e6 | 25 | } |
| shintamainjp | 0:49c0ef6111e6 | 26 | |
| shintamainjp | 0:49c0ef6111e6 | 27 | private: |
| shintamainjp | 0:49c0ef6111e6 | 28 | enum { SemFree, SemTaken }; |
| shintamainjp | 0:49c0ef6111e6 | 29 | int s; |
| shintamainjp | 0:49c0ef6111e6 | 30 | }; |
| shintamainjp | 0:49c0ef6111e6 | 31 | |
| shintamainjp | 0:49c0ef6111e6 | 32 | #endif |