Changeset 178 for trunk

Timestamp:

Oct 9, 2011, 12:31:39 PM (13 years ago)

Author:

alain

Message:

fixing a bug in _barrier_wait function (thanks to Joel for asm)

File:

• trunk/softs/giet_tsar/drivers.c (modified) (3 diffs)

trunk/softs/giet_tsar/drivers.c

@@ -591 +591 @@
 //  I/O BLOCK_DEVICE
 // The three functions below use the three variables _ioc_lock _ioc_done, 
-// and _ioc_status for synchronsation.
+// and _ioc_status for synchronisation.
 // - As the IOC component can be used by several programs running in parallel,
 // the _ioc_lock variable guaranties exclusive access to the device.
@@ -614 +614 @@
 in_drivers void _ioc_get_lock()
 {
-    register unsigned int       delay = (_proctime() & 0xF) << 4;
     register unsigned int*      plock = (unsigned int*)&_ioc_lock;                      
 
-    asm volatile ("_ioc_llsc:                           \n"
+    asm volatile ("_ioc_llsc:                       \n"
                   "ll   $2,    0(%0)                \n" // $2 <= _ioc_lock
-                  "bnez $2,    _ioc_delay           \n" // random delay if busy
-                  "li   $3,    1                            \n" // prepare argument for sc  
+                  "bnez $2,    _ioc_llsc            \n" // retry  if busy
+                  "li   $3,    1                    \n" // prepare argument for sc  
                   "sc   $3,    0(%0)                \n" // try to set _ioc_busy
-                  "bnez $3,    _ioc_ok              \n" // exit if atomic 
-                  "_ioc_delay:                              \n"
-                  "move $4,    %1                           \n" // $4 <= delay
-                  "_ioc_loop:                               \n"
-                  "addi $4,    $4,    -1            \n" // $4 <= $4 - 1
-                  "beqz $4,    _ioc_loop            \n" // test end delay
-                  "j           _ioc_llsc        \n"     // retry
-                  "_ioc_ok:                                 \n"
-                  ::"r"(plock),"r"(delay):"$2","$3","$4");
+                  "beqz $3,    _ioc_llsc            \n" // retry if not atomic 
+                  ::"r"(plock):"$2","$3");
 }
 //////////////////////////////////////////////////////////////////////////////////////
@@ -924 +916 @@
     // output : count = _barrier_count[index] (before decrementation)
     asm volatile ("_barrier_decrement:                          \n"
-                  "or   $2,     %1,     $0                      \n"
-                  "ll   %0,     0($2)                           \n"
+                  "ll   %0,     0(%1)                           \n"
                   "addi $3,     %0,     -1                      \n"
-                  "sc   $3,     0($2)                           \n"
+                  "sc   $3,     0(%1)                           \n"
                   "beqz $3,     _barrier_decrement              \n"
-                  :"=r"(count):"r"(pcount):"$2","$3");
+                  :"=&r"(count)
+                  :"r"(pcount)
+                  :"$2","$3");
 
     // the last task re-initializes the barrier_ count variable