From 4c7af15f04f1007d75c046b5e95dc86cb31f444d Mon Sep 17 00:00:00 2001
From: Andreas Baumann <mail@andreasbaumann.cc>
Date: Wed, 5 Jul 2017 08:42:25 +0200
Subject: fixed graphical screen refresh (a refreshScreen task) cleaned up code
 after interrupt_enable in main thread everything works again

---
 src/kernel/kernel.c | 92 +++++++++++++++++++++++++++--------------------------
 1 file changed, 47 insertions(+), 45 deletions(-)

(limited to 'src')

diff --git a/src/kernel/kernel.c b/src/kernel/kernel.c
index b9beeb1..57f6d28 100644
--- a/src/kernel/kernel.c
+++ b/src/kernel/kernel.c
@@ -33,8 +33,6 @@ static jmp_buf panic_jmp_buf;
 static void handle_keyboard_event( keyboard_event_t *event, void *context );
 static void handle_mouse_event( mouse_event_t *event, void *context );
 
-static bool terminate = false;
-
 typedef enum {
 	MODE_TEXT,
 	MODE_GRAPHICS
@@ -55,8 +53,9 @@ typedef struct {
 
 static global_context_t global_context;
 
-static void funcA( );
-static void funcB( );
+static void funcA( void );
+static void funcB( void );
+static void refresh_screen( void );
 	
 // must be first entry in kernel.bin (0x8800) as stage 2 of
 // the boot loader expects the entry point to be here!
@@ -97,6 +96,9 @@ void kernel_main( void )
 	task_t taskB;
 	task_init( &taskB, GDT_CODE_SEGMENT_SELECTOR, &funcB );
 	task_manager_add_task( &task_manager, &taskB );
+	task_t taskRefreshScreen;
+	task_init( &taskRefreshScreen, GDT_CODE_SEGMENT_SELECTOR, &refresh_screen );
+	task_manager_add_task( &task_manager, &taskRefreshScreen );
 	
 	puts( "Initializing interrupts" );
 	interrupt_t interrupt;
@@ -144,43 +146,15 @@ void kernel_main( void )
 
 	puts( "Enabling interrupt handing now.." );
 	
-	// TODO: if enabling tasks, this could be our really last execution
-	// in the main kernel thread
+	// enabling tasks, this is our really last execution
+	// in the main kernel thread, we never return (but for
+	// termination longjmp to TERMINATE)
 	interrupts_enable( );
-
-	puts( "Running.." );
-
-	// endless loop doing nothing, later we have to get events
-	// here from queues and for instance print characters received
-	// from the keyboard to stdout
-	while( !terminate ) {
-		// for now we are only interested in interrupts,
-		// so we let the main thread sleep instead of
-		// burning CPU..
-		kernel_halt( );
-
-		switch( global_context.mode ) {
-			case MODE_TEXT:
-				// nothing to draw or refresh in text mode, the
-				// VGA card is doing that for us
-				break;
-
-			case MODE_GRAPHICS:
-				// for now we must avoid races with the interrupt
-				// events originating especially from the mouse
-				interrupts_disable( );
-
-				// as vga_t is equals to the graphical context for now
-				((widget_t *)&global_context.desktop)->vtable->draw( &global_context.desktop, &global_context.vga );
-
-				vga_refresh( &global_context.vga );
-
-				interrupts_enable( );
-
-				break;
-		}		
-	}			
 	
+	// we get back here on termination and kernel panic via goto after
+	// longjmp
+	// TODO: make sure we run this part of the code with the original
+	// early kernel stack and not with a task stack!
 TERMINATE:
 	puts( "Deactivating drivers" );
 	driver_manager_deactivate_all( &global_context.driver_manager );
@@ -200,7 +174,7 @@ void kernel_panic( const char *format, ... )
         va_end( args );
 	puts( "" );
 
-	longjmp( panic_jmp_buf, 47 );
+	longjmp( panic_jmp_buf, 47 /* TODO: error code */ );
 }
 
 static void handle_keyboard_event( keyboard_event_t *event, void *context )
@@ -234,7 +208,7 @@ static void handle_keyboard_event( keyboard_event_t *event, void *context )
 							puts( "clear  - clear screen" );
 							puts( "mode   - switch between text/graphics mode" );
 						} else if( strcmp( buf, "halt" ) == 0 ) {
-							terminate = true;
+							longjmp( panic_jmp_buf, 0 );
 						} else if( strcmp( buf, "mem" ) == 0 ) {
 							// TODO: print memory usage
 						} else if( strcmp( buf, "proc" ) == 0 ) {
@@ -378,16 +352,44 @@ static void handle_mouse_event( mouse_event_t *event, void *context )
 	}
 }
 
-static void funcA( )
+static void funcA( void )
 {
 	while( true ) {
-		printf( "A" );
+		//~ printf( "A" );
+		//~ kernel_panic( "panic in task" );
 	}
 }
 
-static void funcB( )
+static void funcB( void )
 {
 	while( true ) {
-		printf( "B" );
+		//~ printf( "B" );
 	}
 }
+
+static void refresh_screen( void )
+{
+	while( true ) {
+		switch( global_context.mode ) {
+			case MODE_TEXT:
+				// nothing to draw or refresh in text mode, the
+				// VGA card is doing that for us
+				break;
+
+			case MODE_GRAPHICS:
+				// for now we must avoid races with the interrupt
+				// events originating especially from the mouse
+				interrupts_disable( );
+
+				// as vga_t is equals to the graphical context for now
+				((widget_t *)&global_context.desktop)->vtable->draw( &global_context.desktop, &global_context.vga );
+
+				vga_refresh( &global_context.vga );
+
+				interrupts_enable( );
+
+				break;
+		}		
+	}
+}			
+
-- 
cgit v1.2.3-54-g00ecf