Design Report

Hacettepe University Computer Science and Engineering Department Name and Surname: Barış Toker Identity Number: 20421986 Course: BİL341 Experiment: Experiment 4 Subject: Operating Systems – PC Interrupt Handling Data Due: 27.11.2007 Advisors: Prof. Dr. Ali Saatçic, R. A. Ersin ER

Type Definitions

typedef void interrupt(*isr_pointer) (); Execution Flow Between Subprograms Description Template <-subprogram name with parameters> 1 - <what it does>, 2 - <what it returns>, 3 - <where it is called>. 4 - <what it calls>. int main(int argc, char* argv); 1 – This is the executable function, it makes the initializations and finalizations, handles the game's flow. 4 – It calls the functions update_idt, restore_idt. void move_orc(Orc orc); 1 – This function is used to move orcs on the screen. 3 – It is called in timer_isr. 4 – It calls the function print_on_screen; void move_player(Player player); 1 – This function is used to move the players on the screen. 3 – It is called in keyboard_isr(); 4 – It calls the function print_on_screen; void print_on_screen(int x_coordinate, int y_coordinate, char ch); - contains assembly code 1 – This function is used to print a charater on the screen at the given coordinate. 3 – It is called in move_orc, move_player, timer_isr; void update_idt(); - contains assembly code 1 – This function is used to update the keyboard and timer interrupt service routines. 3 – It is called in main. 4 – It calls the functions get_isr, set_isr. void restore_idt(); - contains assembly code 1 – This function is used to restore the actual keyboard and timer interrupt service routines. 3 – It is called in main. 4 – It calls the functions get_isr, set_isr. isr_pointer get_isr(int idt_index); - contains assembly code 1 – This function is used to get a pointer to the interrupt service routine at the given IDT index. 2 – It returns a pointer to the relevatn interrupt service routine. 3 – It is called in update_idt, restore_idt. void set_isr(int idt_index, isr_Pointer isr);

1 – This function is used to set the interrupt service routine at the given IDT index with function pointed with isr. 3 – It is called in update_idt, restore_idt. void interrupt keyboard_isr(); - contains assembly code 1 – This function is used to handle keyboard interrupts. 3 – It is called when a key is pressed on the keyboard. 4 – It calls the function move_player; void interrupt timer_isr(); - contains assembly code 1 – This function is used to handle the timer interrupt. It moves the orcs at a certain frequency and prints the time elapsed at the screen. 4 – It calls the functions move_orc, print_on_screen.