1 files changed, 158 insertions, 0 deletions
diff --git a/thread.c b/thread.c
new file mode 100644
index 0000000..46e0d42
--- /dev/null
+++ b/thread.c
@@ -0,0 +1,158 @@
+/************************************************************************/
+/*                                                                      */
+/*  File:           thread.c                                            */
+/*  Description:    thread implementation.                              */
+/*  Version:        1.0                                                 */
+/*  Author:         Otto Mattik                                         */
+/*                                                                      */
+/*  (C)Copyright Otto Mattik 2014-2021.                                 */
+/*                                                                      */
+/*  This file is a part of 'armen' (a tiny operating system).           */
+/*  'armen' is distributed under the CeCILL-V2.1 licence. For more      */
+/*  details about this licence, please visit the website cecill.info    */
+/*                                                                      */
+/************************************************************************/
+
+#include "core.h"
+
+uint8_t volatile _cur_thread;
+_thread_t _threads[ARMEN_THREADS];
+
+/*
+ * identifier of calling thread
+ *
+ * input:
+ * output:
+ *  thread identifier
+*/
+thread_t thread_self( void )
+{
+    return( _cur_thread );
+}
+
+/*
+ * create a thread
+ *
+ * input:
+ *  start       start routine of new thread
+ *  arg         argument of start routine
+ * output:
+ *  thread identifier if success, otherwise -1
+*/
+thread_t thread_create( void* (*start)(void*), void* arg )
+{
+    register uint8_t i, iflag;
+
+    iflag = _disable_intr( );
+    for( i = 1; i < ARMEN_THREADS; i++ )
+    {
+        register _thread_t* pthread = &_threads[i];
+
+        if( pthread->status == TS_UNUSED )
+        {
+            pthread->rank = 127;
+            pthread->order = 0;
+            pthread->entry = start;
+            pthread->param = arg;
+            pthread->cstack = _init_context( start, arg, pthread->istack );
+            pthread->status = TS_RUNNING;
+            break;
+        }
+    }
+    _enable_intr( iflag );
+    return( i == ARMEN_THREADS ? -1 :  i );
+}
+
+/*
+ * terminate the calling thread
+ *
+ * input:
+ *  thread      thread identifier
+ *  retval      value will be returned (see thread_join)
+ * output:
+*/
+static void _thread_exit_( thread_t thread, void* retval )
+{
+    _disable_intr( );
+    _threads[thread].status = TS_UNUSED;
+    _wakeup( EVENT_JOIN, retval );
+    _schedule( );
+}
+void _thread_exit( void )
+{
+    _thread_exit_( _cur_thread, 0 );
+}
+void thread_exit( void* retval )
+{
+    _thread_exit_( _cur_thread, retval );
+}
+
+#ifdef USE_FULL_THREAD
+
+  /*
+   * send a cancellation request to a thread
+   *
+   * input:
+   *  thread      thread identifier
+   * output:
+  */
+  void thread_cancel( thread_t thread )
+  {
+    if(
+  #ifdef CHECK_PARAM
+        thread > 0 && thread < ARMEN_THREADS &&
+  #endif
+        thread != _cur_thread
+    &&  _threads[thread].status != TS_UNUSED )
+        _thread_exit_( thread, (void*)-1 );
+  }
+
+  /*
+   * wait for termination of a thread
+   *
+   * input:
+   *  thread      thread identifier
+   *  retval      address of exit value (see thread_exit)
+   * output:
+  */
+  void thread_join( thread_t thread, void** retval )
+  {
+    if(
+  #ifdef CHECK_PARAM
+        thread > 0 && thread < ARMEN_THREADS &&
+  #endif
+        thread != _cur_thread
+    &&  _threads[thread].status != TS_UNUSED )
+    {
+        wait_event( EVENT_JOIN );
+        _schedule( );
+        if( retval != (void**)0)
+            *retval = _threads[_cur_thread].param;
+    }
+  }
+
+  /*
+   * change the priority of a thread
+   *
+   * input:
+   *  thread      thread identifier
+   *  priority    new priority (1 hightest to 254 lowest)
+   *              if 0, just return the current priority
+   * output:
+   *  priority if success, otherwise -1
+  */
+  uint8_t thread_nice( thread_t thread, uint8_t priority )
+  {
+    if(
+  #ifdef CHECK_PARAM
+        thread <= 0 || thread >= ARMEN_THREADS ||
+  #endif
+        _threads[thread].status == TS_UNUSED )
+        return( 255 );
+
+    if( priority != 0 )
+        _threads[thread].rank = priority;
+    return( _threads[thread].rank );
+  }
+
+#endif