From e5888a1ffdae813d7575f5fb02275c6bb07e5199 Mon Sep 17 00:00:00 2001 From: Taru Karttunen Date: Wed, 30 Mar 2011 15:46:40 +0300 Subject: Import sources from 2011-03-30 iso image --- sys/src/ape/lib/ap/power/lock.c | 45 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100755 sys/src/ape/lib/ap/power/lock.c (limited to 'sys/src/ape/lib/ap/power/lock.c') diff --git a/sys/src/ape/lib/ap/power/lock.c b/sys/src/ape/lib/ap/power/lock.c new file mode 100755 index 000000000..0d17c34d5 --- /dev/null +++ b/sys/src/ape/lib/ap/power/lock.c @@ -0,0 +1,45 @@ +#include "../plan9/lib.h" +#include "../plan9/sys9.h" +#define _LOCK_EXTENSION +#include + +int tas(int*); + +void +lock(Lock *lk) +{ + int i; + + /* once fast */ + if(!tas(&lk->val)) + return; + /* a thousand times pretty fast */ + for(i=0; i<1000; i++){ + if(!tas(&lk->val)) + return; + _SLEEP(0); + } + /* now nice and slow */ + for(i=0; i<1000; i++){ + if(!tas(&lk->val)) + return; + _SLEEP(100); + } + /* take your time */ + while(tas(&lk->val)) + _SLEEP(1000); +} + +int +canlock(Lock *lk) +{ + if(tas(&lk->val)) + return 0; + return 1; +} + +void +unlock(Lock *lk) +{ + lk->val = 0; +} -- cgit v1.2.3