Added wait syscall.

This makes a process sleep until it receives a new message (no polling!).
I thought that this will result in performance improvements but I haven't
noticed any, yet. Maybe I'll remove this again in the future..

7 files changed, 52 insertions, 7 deletions

diff --git a/apps/init.c b/apps/init.c
index ba6f93e..ccf88dd 100644
--- a/apps/init.c
+++ b/apps/init.c
@@ -13,5 +13,8 @@ int main(int argc, char **argv)
 	/* int test = exec("/window", "test", NULL); */
 	int mandelbrot = exec("/mandelbrot", "mandelbrot", NULL);
 
+	while (1) {
+		yield();
+	};
 	return wm + mandelbrot;
 }
diff --git a/apps/mandelbrot.c b/apps/mandelbrot.c
index d5b8ae0..9f73501 100644
--- a/apps/mandelbrot.c
+++ b/apps/mandelbrot.c
@@ -49,7 +49,6 @@ void draw_mandelbrot(struct window *win, int resolution)
 	}
 	gui_redraw();
 	print("Rendered mandelbrot successfully\n");
-	yield();
 }
 
 int main()
@@ -62,7 +61,7 @@ int main()
 	draw_mandelbrot(win, 50);
 
 	while (1) {
-		yield();
+		wait();
 	};
 
 	return 0;
diff --git a/apps/wm.c b/apps/wm.c
index 477eb7f..d4db938 100644
--- a/apps/wm.c
+++ b/apps/wm.c
@@ -12,7 +12,7 @@
 #include <sys.h>
 #include <vesa.h>
 
-#define MOUSE_SKIP 4 // => Every nth move gets skipped
+#define MOUSE_SKIP 5 // => Every move % n != 0 gets skipped
 
 static struct vbe *vbe;
 static struct window *direct; // Direct video memory window
@@ -84,7 +84,7 @@ int main(int argc, char **argv)
 	int mouse_skip = 0;
 	while (1) {
 		if (!(msg = msg_receive())) {
-			yield();
+			wait();
 			continue;
 		}
 
diff --git a/kernel/features/proc.c b/kernel/features/proc.c
index a5df875..19845d4 100644
--- a/kernel/features/proc.c
+++ b/kernel/features/proc.c
@@ -40,6 +40,15 @@ void scheduler(struct regs *regs)
 	else
 		current = proc_list->head;
 
+	while (((struct proc *)current->data)->state == PROC_WAITING) {
+		/* assert(proc_awake() > 0); */
+		if (current && current->next && current->next->data) {
+			current = current->next;
+		} else {
+			current = proc_list->head;
+		}
+	}
+
 	memcpy(regs, &((struct proc *)current->data)->regs, sizeof(struct regs));
 
 	if (regs->cs != GDT_USER_CODE_OFFSET) {
@@ -55,6 +64,16 @@ void scheduler(struct regs *regs)
 	/* printf("{%d}", ((struct proc *)current->data)->pid); */
 }
 
+void scheduler_enable()
+{
+	irq_install_handler(0, scheduler);
+}
+
+void scheduler_disable()
+{
+	irq_install_handler(0, timer_handler);
+}
+
 void proc_print()
 {
 	struct node *node = proc_list->head;
@@ -73,6 +92,17 @@ struct proc *proc_current()
 	return current && current->data ? current->data : NULL;
 }
 
+int proc_awake()
+{
+	int ret = 0;
+	struct node *iterator = proc_list->head;
+	do {
+		if (((struct proc *)iterator->data)->state != PROC_WAITING)
+			ret++;
+	} while ((iterator = iterator->next) != NULL);
+	return ret;
+}
+
 void proc_send(struct proc *src, struct proc *dest, enum message_type type, void *data)
 {
 	// TODO: Use unique key instead of pid for IPC messaging
@@ -85,6 +115,8 @@ void proc_send(struct proc *src, struct proc *dest, enum message_type type, void
 	msg->msg->type = type;
 	msg->msg->data = data;
 	list_add(dest->messages, msg);
+	if (dest->state == PROC_WAITING)
+		dest->state = PROC_DEFAULT;
 }
 
 struct proc_message *proc_receive(struct proc *proc)
@@ -159,7 +191,7 @@ void proc_init()
 		return;
 
 	cli();
-	irq_install_handler(0, scheduler);
+	scheduler_enable();
 	proc_list = list_new();
 
 	kernel_proc = proc_make();
diff --git a/kernel/features/syscall.c b/kernel/features/syscall.c
index 25770a4..b3af455 100644
--- a/kernel/features/syscall.c
+++ b/kernel/features/syscall.c
@@ -17,7 +17,7 @@ void syscall_handler(struct regs *r)
 	enum sys num = r->eax;
 	r->eax = 0;
 
-	if (num != SYS_RECEIVE && num != SYS_YIELD && num != SYS_TIME)
+	if (num != SYS_RECEIVE && num != SYS_YIELD && num != SYS_WAIT && num != SYS_TIME)
 		printf("[SYSCALL] %d from %s: ", num, proc_current()->name);
 
 	switch (num) {
@@ -74,6 +74,12 @@ void syscall_handler(struct regs *r)
 		proc_yield(r);
 		break;
 	}
+	case SYS_WAIT: {
+		/* printf("wait\n"); */
+		proc_current()->state = PROC_WAITING;
+		proc_yield(r);
+		break;
+	}
 	case SYS_TIME: {
 		/* printf("time\n"); */
 		r->eax = timer_get();
diff --git a/kernel/inc/proc.h b/kernel/inc/proc.h
index 2335d5d..9d4906d 100644
--- a/kernel/inc/proc.h
+++ b/kernel/inc/proc.h
@@ -17,7 +17,7 @@
 #define GDT_USER_CODE_OFFSET 0x1b // User code segment offset in GDT (with ring3 mask)
 #define GDT_USER_DATA_OFFSET 0x23 // User data segment offset in GDT (with ring3 mask)
 
-enum proc_state { PROC_DEFAULT };
+enum proc_state { PROC_DEFAULT, PROC_WAITING };
 
 struct proc {
 	u32 pid;
@@ -36,9 +36,12 @@ struct proc_message {
 
 struct proc *kernel_proc;
 
+void scheduler_enable();
+void scheduler_disable();
 void proc_init();
 void proc_print();
 struct proc *proc_current();
+int proc_awake();
 void proc_send(struct proc *src, struct proc *dest, enum message_type type, void *data);
 struct proc_message *proc_receive(struct proc *proc);
 struct proc *proc_from_pid(u32 pid);
diff --git a/libc/inc/sys.h b/libc/inc/sys.h
index 073ccd2..1b01127 100644
--- a/libc/inc/sys.h
+++ b/libc/inc/sys.h
@@ -16,6 +16,7 @@ enum sys {
 	SYS_EXEC, // Execute path
 	SYS_EXIT, // Exit current process
 	SYS_YIELD, // Switch to next process
+	SYS_WAIT, // Sleep until new message arrives
 	SYS_TIME, // Get kernel time
 	SYS_REGISTER, // Register for event
 	SYS_UNREGISTER, // Unregister event
@@ -71,6 +72,7 @@ int sysv(enum sys num, ...);
 		}                                                                                  \
 	}
 #define yield() (int)sys0(SYS_YIELD)
+#define wait() (int)sys0(SYS_WAIT)
 #define time() (int)sys0(SYS_TIME)
 
 #define event_register(id) sys1(SYS_REGISTER, (int)(id))