Mouse Question

1
Mouse Question 1

• Which INT number is used for the mouse?

2
Mouse Question1

• Which INT number is used for the mouse?
• 33h

3
Question 1A

• Unlike DOS INT 21h, or BIOS INT10h, with the
  mouse BIOS functions, the function number is
  selected through the _________ register.

4
Question 1A

• Unlike DOS INT 21h, or BIOS INT10h, with the
  mouse BIOS functions, the function number is
  selected through the ____AL_____ register.

5
Question 2

• Write ASM statements that reset the mouse and get
  the mouse status.

6
Need to find out

• Which INT 33h function handles resetting the
  mouse and getting the status?
• Look at slides
• Look in book page 566-574

7
Resetting Mouse Returns

• If mouse is found,
• AX FFFFh
• BX number of mouse buttons
• If no mouse found,
• AX 0

8
Question 2 Solutions

• Write ASM statements that reset the mouse and get
  the mouse status.
• Mov ax, 0 int 33h, function 0
• Int 33h status returned in ax
• Cmp ax, 0 if ax0, mouse not available

9
Comments about resetting mouse

• If mouse is found
• It is centered on the screen
• Its display page is set to video page 0
• Its pointer is hidden
• Its mickeys are set to pixels ratio
• Its speed is set to default values
• Its range of movement is set to the entire
  screen area.

10
Question 3

• Which INT 33h function shows and hides the mouse
  pointer?

11
Question 3 Solutions

• Which INT 33h function shows and hides the mouse
  pointer?
• Function 1 show
• Function 2 - hide

12
Question 4

• Write ASM statements that hide the mouse pointer.

13
Question 4

• Write ASM statements that hide the mouse pointer.
• Mov ax, 2
• Int 33h

14
Comments about mouse pointer

• Mouse driver keeps a counter
• Incremented (if nonzero) by calls to function 1
• Decremented by calls to function 2
• When counter is 0, pointer is displayed
• Function 0 (reset mouse pointer) sets counter to
  1.

15
Question 5

• Which INT 33h function gets the mouse position
  and status?

16
Question 5

• Which INT 33h function gets the mouse position
  and status?
• Function 3

17
Question 6

• Write ASM statements that get the mouse position
  and store it in the variables mouseX and mouseY.

18
Before Answering,Need to Know..

• What is returned
• BX mouse button status
• If bit 0 is set, left button is down
• If bit 1 is set, right button is down
• If bit 2 is set, middle button is down
• CX X-Coordinate
• DX Y-Coordinate

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Question 6 Solutions

• Write ASM statements that get the mouse position
  and store it in the variables mouseX and mouseY.
• mov ax, 3
• int 33h
• mov mouseX, CX
• mov mouseY, DX

20
Question 7

• Which INT 33h function sets the mouse position?

21
Question 7

• Which INT 33h function sets the mouse position?
• Function 4

22
Question 8

• Write ASM statements that set the mouse pointer
  to X100 and Y 400.

23
Before Answering Need to know

• What to send
• CX X-Coordinate
• DX Y-Coordinate

24
Question 8

• Write ASM statements that set the mouse pointer
  to X100 and Y 400.
• Mov ax, 4
• mov cx, 100
• mov dx, 400
• int 33h

25
Question 9

• Which INT 33h function gets the mouse button
  press information?

26
Question 9

• Which INT 33h function gets the mouse button
  press information?
• Function 5

27
Question 10

• Write ASM statements that jump to label Button1
  when the left mouse button has been pressed.

28
Before Answering,Need to know

• What to send
• BX Button ID (0left, 1right, 2center)
• What is returned.
• AX button status
• BX button press counter
• CX X-coordinate of last button press
• DX Y-coordinate of last button press

29
Question 10 Solutions

• Write ASM statements that jump to label Button1
  when the left mouse button has been pressed.
• mov ax, 5
• mov bx, 0
• int 33h
• tst ax, 0
• jz Button1

30
Comments about Button Press

• In an event-driven programming environment, a
  drag event always begins with a button press.
• Once a call is made to this function for a
  particular button, the buttons state is reset,
  and a second call to the function returns nothing.

31
Question 11

• Which INT 33h function gets button release
  information?

32
Question 11

• Which INT 33h function gets button release
  information?
• Function 6

33
Question 12

• Write ASM statements that get the mouse position
  at the point when the right button was released,
  and store the position in the variables mouseX
  and mouseY.

34
Question 12

• Write ASM statements that get the mouse position
  at the point when the right button was released,
  and store the position in the variables mouseX
  and mouseY.
• mov ax, 6
• mov bx, 1
• int 33h
• mov mouseX, CX
• mov mouseY, DX

35
Question 13

• Write ASM statements that set the vertical limits
  of the mosue to 200 and 400.

36
Question 13

• Write ASM statements that set the vertical limits
  of the mouse to 200 and 400.
• mov ax, 8
• mov CX, 200
• mov DX, 400
• int 33h

37
Question 14

• Write ASM statements that set the horizontal
  limits of the mouse to 300 and 600.

38
Question 14

• Write ASM statements that set the horizontal
  limits of the mouse to 300 and 600.
• mov ax, 7
• mov cx, 300
• mov dx, 400
• int 33h