got scheduling of task A and B working (now graphics output and termination is broken)

6 files changed, 86 insertions, 27 deletions

diff --git a/src/hardware/interrupts.asm b/src/hardware/interrupts.asm
index 155b2af..30204e7 100644
--- a/src/hardware/interrupts.asm
+++ b/src/hardware/interrupts.asm
@@ -53,6 +53,8 @@ IRQ_BASE equ 0x20
 global interrupts_handle_irq_%1
 interrupts_handle_irq_%1:
 	mov [interrupt_no], byte IRQ_BASE + %1
+	; error
+	push 0x0
 	jmp int_entry
 %endmacro
 
@@ -62,11 +64,18 @@ irq_stub 0x0C
 
 int_entry:
 	; safe state of interrupted code
-	pusha
-	push ds
-	push es
-	push fs
-	push gs
+	;pusha
+	push ebp
+	push edi
+	push esi
+	push edx
+	push ecx
+	push ebx
+	push eax
+	;push ds
+	;push es
+	;push fs
+	;push gs
 
 	; call the static C handler with the correct interrupt number
 	; uint32_t interrupts_handle_interrupt( uint8_t interrupt_no, uint32_t esp );
@@ -74,15 +83,25 @@ int_entry:
 	mov eax, [interrupt_no]
 	push eax
 	call interrupts_handle_static_interrupt
-	;add esp, 8
+	; switch stack
 	mov esp, eax
 
-	; restore state
-	pop gs
-	pop fs
-	pop es
-	pop ds
-	popa
+	; restore state (no popa or pusha, we have to align to cpu_state in tasks.h)
+	;pop gs
+	;pop fs
+	;pop es
+	;pop ds
+	;popa
+	pop eax
+	pop ebx
+	pop ecx
+	pop edx
+	pop esi
+	pop edi
+	pop ebp
+	
+	; remove error from the stack
+	add esp, 4
 	
 	iret
 
diff --git a/src/hardware/interrupts.c b/src/hardware/interrupts.c
index 614dbf0..4ca0f14 100644
--- a/src/hardware/interrupts.c
+++ b/src/hardware/interrupts.c
@@ -7,9 +7,6 @@
 
 #include "keyboard.h"
 
-// TODO: for now the code segment is the first entry in the boot GDT	
-#define GDT_CODE_SEGMENT_SELECTOR 8
-
 // the Present bit in a IDT entry
 #define IDT_PRESENT_BIT 0x80
 
@@ -75,15 +72,17 @@ void interrupt_handler_init( interrupt_handler_t *handler, uint8_t interrupt_no,
 // of the interrupt handler structure
 static interrupt_t *active_interrupt;
 
-void interrupts_init( interrupt_t *interrupt )
+void interrupts_init( interrupt_t *interrupt, uint16_t gdt_code_segment_selector, task_manager_t *task_manager )
 {
 	memset( interrupt, 0, sizeof( interrupt_t ) );
 	
 	interrupt_handler_t empty_interrupt_handler;
 	interrupt_handler_init_void( &empty_interrupt_handler );
+	
+	interrupt->task_manager = task_manager;
 
 	for( int i = 0; i < NOF_INTERRUPTS; i++ ) {
-		interrupts_register_interrupt_gate( interrupt, i, GDT_CODE_SEGMENT_SELECTOR,
+		interrupts_register_interrupt_gate( interrupt, i, gdt_code_segment_selector,
 			&interrupts_ignore_request, KERNEL_RING, IDT_TYPE_INTERRUPT_GATE );
 		interrupts_register_interrupt_handler( empty_interrupt_handler );
 	}
@@ -92,7 +91,7 @@ void interrupts_init( interrupt_t *interrupt )
 	interrupt_handler_t divide_by_zero_interrupt_handler;
 	interrupt_handler_init( &divide_by_zero_interrupt_handler, 0x00, interrupt, interrupts_exception_division_by_zero, NULL );
 	
-	interrupts_register_interrupt_gate( interrupt, 0x00, GDT_CODE_SEGMENT_SELECTOR,
+	interrupts_register_interrupt_gate( interrupt, 0x00, gdt_code_segment_selector,
 		&interrupts_handle_exception_0x00, KERNEL_RING, IDT_TYPE_INTERRUPT_GATE );
 	interrupts_register_interrupt_handler( divide_by_zero_interrupt_handler );
 
@@ -100,16 +99,16 @@ void interrupts_init( interrupt_t *interrupt )
 	interrupt_handler_t pit_interrupt_handler;
 	interrupt_handler_init( &pit_interrupt_handler, IRQ_BASE + 0x00, interrupt, interrupts_interrupt_PIT, NULL );
 	
-	interrupts_register_interrupt_gate( interrupt, IRQ_BASE + 0x00, GDT_CODE_SEGMENT_SELECTOR,
+	interrupts_register_interrupt_gate( interrupt, IRQ_BASE + 0x00, gdt_code_segment_selector,
 		&interrupts_handle_irq_0x00, KERNEL_RING, IDT_TYPE_INTERRUPT_GATE );
 	interrupts_register_interrupt_handler( pit_interrupt_handler );
 
 	// IRQ 1 - PS/2 keyboard
-	interrupts_register_interrupt_gate( interrupt, IRQ_BASE + 0x01, GDT_CODE_SEGMENT_SELECTOR,
+	interrupts_register_interrupt_gate( interrupt, IRQ_BASE + 0x01, gdt_code_segment_selector,
 		&interrupts_handle_irq_0x01, KERNEL_RING, IDT_TYPE_INTERRUPT_GATE );
 
 	// IRQ 12 - PS/2 mouse
-	interrupts_register_interrupt_gate( interrupt, IRQ_BASE + 0x0C, GDT_CODE_SEGMENT_SELECTOR,
+	interrupts_register_interrupt_gate( interrupt, IRQ_BASE + 0x0C, gdt_code_segment_selector,
 		&interrupts_handle_irq_0x0C, KERNEL_RING, IDT_TYPE_INTERRUPT_GATE );
 	
 	port8_init( &interrupt->PIC_master_control, 0x20 );
@@ -202,8 +201,13 @@ uint32_t interrupts_handle_interrupt( interrupt_t *interrupt, uint8_t interrupt_
 	}
 
 	uint32_t new_esp = handler->handle( handler, esp );
-
-	// send ACK to PIC for hardware interrups
+	
+	// timer interrupt, schedule the tasks
+	if( interrupt_no == IRQ_BASE + 0x00 ) {
+		new_esp = (uint32_t)task_manager_schedule_task( interrupt->task_manager, (cpu_state_t *)esp );
+	}
+	
+	// send ACK to PIC for hardware interrupts
 	if( interrupt_no >= IRQ_BASE && interrupt_no <= IRQ_BASE + 16 ) {
 		port8_write( &interrupt->PIC_master_control, OCW2_EOI );
 		if( interrupt_no >= IRQ_BASE + 8 ) {
diff --git a/src/hardware/interrupts.h b/src/hardware/interrupts.h
index 8ab485e..767bb2e 100644
--- a/src/hardware/interrupts.h
+++ b/src/hardware/interrupts.h
@@ -4,6 +4,7 @@
 #include <stdint.h>
 
 #include "port.h"
+#include "tasks.h"
 
 // total number of supported interrupts
 #define NOF_INTERRUPTS 256
@@ -11,6 +12,11 @@
 // offset for hardware interrupts
 #define IRQ_BASE 0x20
 
+// TODO: for now the code segment is the first entry in the boot GDT	
+// temporary, should be a gdt module with functions to retrieve the
+// current code segment selector
+#define GDT_CODE_SEGMENT_SELECTOR 8
+
 // TCC 0.9.26 bug?, __attribute__( ( packed ) ) on structs not working,
 // also not working on members.. resorting to pragmas
 #if defined( __TINYC__ )
@@ -64,6 +70,7 @@ typedef struct interrupt_t {
 	interrupt_descriptor_table_pointer_t idt_pointer;
 	interrupt_gate_descriptor_t descriptor_table[NOF_INTERRUPTS];
 	interrupt_handler_t interrupt_handler[NOF_INTERRUPTS];
+	task_manager_t *task_manager;
 	// PIC master control register: command and status register
 	port8_t PIC_master_control;
 	// PIC master data register: interrupt mask and data register
@@ -76,7 +83,7 @@ typedef struct interrupt_t {
 
 void interrupts_enable( void );
 void interrupts_disable( void );
-void interrupts_init( interrupt_t *interrupt );
+void interrupts_init( interrupt_t *interrupt, uint16_t gdt_code_segment_selector, task_manager_t *task_manager );
 void interrupts_register_interrupt_gate( interrupt_t *interrupt,
 	uint8_t interrupt_no, uint16_t gdt_code_segment_selector,
 	void (*helper_handler)( ), uint8_t privilege_level, uint8_t descriptor_type );
diff --git a/src/kernel/kernel.c b/src/kernel/kernel.c
index 9a9f32e..b9beeb1 100644
--- a/src/kernel/kernel.c
+++ b/src/kernel/kernel.c
@@ -26,6 +26,8 @@
 #include "text_widget.h"
 #include "window.h"
 
+#include "tasks.h"
+
 static jmp_buf panic_jmp_buf;
 
 static void handle_keyboard_event( keyboard_event_t *event, void *context );
@@ -53,6 +55,9 @@ typedef struct {
 
 static global_context_t global_context;
 
+static void funcA( );
+static void funcB( );
+	
 // must be first entry in kernel.bin (0x8800) as stage 2 of
 // the boot loader expects the entry point to be here!
 void kernel_main( void )
@@ -83,9 +88,19 @@ void kernel_main( void )
 		goto TERMINATE;
 	}
 
+	// TODO: two demo tasks for now, later we should do something useful in a task
+	task_manager_t task_manager;
+	task_manager_init( &task_manager );
+	task_t taskA;
+	task_init( &taskA, GDT_CODE_SEGMENT_SELECTOR, &funcA );
+	task_manager_add_task( &task_manager, &taskA );
+	task_t taskB;
+	task_init( &taskB, GDT_CODE_SEGMENT_SELECTOR, &funcB );
+	task_manager_add_task( &task_manager, &taskB );
+	
 	puts( "Initializing interrupts" );
 	interrupt_t interrupt;
-	interrupts_init( &interrupt );
+	interrupts_init( &interrupt, GDT_CODE_SEGMENT_SELECTOR, &task_manager );
 
 	puts( "Initializing drivers" );
 	driver_manager_init( &global_context.driver_manager );
@@ -362,3 +377,17 @@ static void handle_mouse_event( mouse_event_t *event, void *context )
 			break;
 	}
 }
+
+static void funcA( )
+{
+	while( true ) {
+		printf( "A" );
+	}
+}
+
+static void funcB( )
+{
+	while( true ) {
+		printf( "B" );
+	}
+}
diff --git a/src/kernel/tasks.c b/src/kernel/tasks.c
index 164409a..4dd7f38 100644
--- a/src/kernel/tasks.c
+++ b/src/kernel/tasks.c
@@ -3,7 +3,7 @@
 #include "kernel.h"
 #include "string.h"
 
-void task_init( task_t *task, uint16_t gdt_code_segment_selector, task_func_t *entrypoint )
+void task_init( task_t *task, uint16_t gdt_code_segment_selector, task_func_t entrypoint )
 {
 	memset( task, 0, sizeof( task_t ) );
 	
diff --git a/src/kernel/tasks.h b/src/kernel/tasks.h
index 604c463..523631b 100644
--- a/src/kernel/tasks.h
+++ b/src/kernel/tasks.h
@@ -47,7 +47,7 @@ typedef struct {
 
 typedef void (*task_func_t)( void );
 
-void task_init( task_t *task, uint16_t gdt_code_segment_selector, task_func_t *entrypoint );
+void task_init( task_t *task, uint16_t gdt_code_segment_selector, task_func_t entrypoint );
 
 #define MAX_NOF_TASKS 256