1

lwt/lwt.c

@@ -0,0 +1,85 @@
+/* lwt.c
+ * Pradeep, Yang
+ */
+
+#ifndef __LWT_H__
+#define __LWT_H__
+#include <pthread.h>
+#define MAX_THD 64
+#define LWT_NULL NULL
+
+lwt_t lwt_pool[MAX_THD];// a thread pool for reuse, or a table to get tcb pointer by its id
+int Queue[MAX_THD];// a queue to store living thread
+int queue_length=0;
+
+lwt_t current_thd;//global pointer to current executing thread
+
+int runnable_num=1;
+int blocked_num=0;
+int zombies_num=0;//global variable for lwt_info
+
+
+lwt_t lwt_create(lwt_fn_t fn, void *data){
+	// set stack, add id to queue and update length
+}
+
+
+void* lwt_join(lwt_t thd_handle){
+	// wait for a thread
+}
+
+void* lwt_die(void *ret){
+	// kill current thread
+}
+
+void lwt_yield(lwt_t thd_handle){
+	// yield current thread and call schedule funtion
+}
+
+lwt_t lwt_current(){
+	// return a pointer to current thread
+	return current_thd;
+}//done
+
+int lwt_id(lwt_t thd){
+	// return the unique id for the thread
+	return thd->id;
+}//done
+
+int lwt_info(lwt_info_t t){
+	// debugging helper
+	switch(t){
+		case LWT_INFO_NTHD_RUNNABLE:
+			return runnable_num;
+		case LWT_INFO_NTHD_BLOCKED:
+			return blocked_num;
+		case LWT_INFO_NTHD_ZOMBIES:
+			return zombies_num;
+		case default:
+			return 0;
+	}
+}//done
+
+/*
+    * Internal functions.
+     */
+void __ lwt_schedule(void){
+	// scheduling
+}
+
+void __lwt_dispatch(lwt_t next, lwt_t current){
+	// context switch from current to next
+}
+
+void __lwt_trampoline(){
+	// ?
+}
+
+void *__lwt_stack_get(void){
+	// allocate a new stack for a new lwt
+}
+
+void *__lwt_stack_return(void *stk){
+	// recover memory for a lwt's stack for reuse 
+}
+

lwt/lwt.h

@@ -1,17 +1,54 @@
+/* lwt.h	
+ * Pradeep, Yang
+ */
+
 #ifndef __LWT_H__
 #define __LWT_H__
 
+#define LWT_NULL NULL
+
 typedef void* (*lwt_fn_t) (void *);
 
+typedef enum{
+	RUN=1,
+	WAIT,
+	READY,
+	COMPLETE
+}lwt_status_t;
+
+/* data structures */
+struct lwt_tcb{		//thread control block;
+	void* ip;
+	void* sp;
+	void* bp;
+        void* return_value;
+        lwt_fn_t fn;   
+        void* data;
+	int id;//we may keep a lwt_t array or pool to store all lwt with id as its index, and a current queue to store ids for all currently living lwt
+        lwt_status_t tcb_status; 
+	int queue_index;
+};
+
+typedef struct lwt_tcb* lwt_t;	//a pointer to tcb, use it as pthread_t
+typedef struct lwt_tcb tcb;
+
+typedef enum{
+	LWT_INFO_NTHD_RUNNABLE=0,
+	LWT_INFO_NTHD_BLOCKED,
+	LWT_INFO_NTHD_ZOMBIES
+}lwt_info_t;
 
 /*
  * lightweight thread APIs.
  */
+
+void lwt_init(unsigned int thread_pool_size);
+
 lwt_t lwt_create(lwt_fn_t fn, void* data);
 
 void* lwt_join(lwt_t thd_handle);
 
-void* lwt_die(void *ret);
+void lwt_die(void *ret);
 
 void lwt_yield(lwt_t thd_handle);
 
@@ -24,14 +61,15 @@ int lwt_info(lwt_info_t t);
 /*
  * Internal functions.
  */
-void __ lwt_schedule(void);
+void __lwt_schedule(void);
 
-void __lwt_dispatch(lwt_t next, lwt_t current);
+void __lwt_dispatch(lwt_t current, lwt_t next);
 
 void __lwt_trampoline();
 
 void *__lwt_stack_get(void);
 
-void *__lwt_stack_return(void *stk);
+void __lwt_stack_return(void *stk);
 
+void __lwt_dequeue(lwt_t thd);
 #endif