1. Virtual Memory

3. public class VMKernel extends UserKernel {

4. “Allocate a new VM kernel.”

5. public VMKernel() {

6. Super(); “this funtion for called proccess”

7. }

8. “Initialize this kernel. ”

9. public void initialize(String[] args) {

10. super.initialize(args);

11. }

13. public void selfTest() {

14. super.selfTest();

15. }

16. “Start running user programs.”

17. public void run() {

18. super.run();

19. }

21. public void terminate() {

22. super.terminate();

23. }

24. // dummy variables to make javac smarter

25. private static VMProcess dummy1 = null;

26. private static final char dbgVM = 'v';

27. }

29. “ Allocate a new process.”

30. public VMProcess() {

31. super();

32. }

33. “Save the state of this process in preparation for a context switch.”

34. “Called by UThread.saveState()”

35. public void saveState() {

36. super.saveState();

37. }

39. public void restoreState() {

40. super.restoreState();

41. }

42. “Initializes page tables for this process so that the executable can be demand-paged.”

43. protected boolean loadSections() {

44. return super.loadSections();

45. }

47. “The cause argument identifies which exception occurred; see the Processor.exception constants.”

48. public void handleException(int cause) {

49. Processor processor = Machine.processor();

50. switch (cause) {

51. default:

52. super.handleException(cause);

53. break;

54. }

55. }

56. private static final int pageSize = Processor.pageSize;

57. private static final char dbgProcess = 'a';

58. private static final char dbgVM = 'v';

59. }