Mouse Question #1

• Which INT number is used for the mouse?

Mouse Question#1

• Which INT number is used for the mouse?

33h

Question #1A

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

Question #1A

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

Question #2

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

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

Resetting Mouse Returns

• If mouse is found,– AX = FFFFh– BX = number of mouse buttons

• If no mouse found,– AX = 0

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 ax=0, mouse not available

Comments about resetting mouse

• If mouse is found: – It is centered on the screen– It’s display page is set to video page 0– It’s pointer is hidden– It’s mickey’s are set to pixels ratio– It’s speed is set to default values– It’s range of movement is set to the entire

screen area.

Question #3

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

Question #3 Solutions

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

Function 1 – show

Function 2 - hide

Question #4

• Write ASM statements that hide the mouse pointer.

Question #4

• Write ASM statements that hide the mouse pointer.

Mov ax, 2

Int 33h

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.

Question #5

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

Question #5

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

Function 3

Question #6

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

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

Question #6 Solutions

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

mov ax, 3int 33hmov mouseX, CXmov mouseY, DX

Question #7

• Which INT 33h function sets the mouse position?

Question #7

• Which INT 33h function sets the mouse position?

Function 4

Question #8

• Write ASM statements that set the mouse pointer to X=100 and Y = 400.

Before Answering Need to know…

What to send…

• CX = X-Coordinate

• DX = Y-Coordinate

Question #8

• Write ASM statements that set the mouse pointer to X=100 and Y = 400.

Mov ax, 4

mov cx, 100

mov dx, 400

int 33h

Question #9

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

Question #9

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

Function 5

Question #10

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

Before Answering,Need to know …

• What to send…• BX = Button ID (0=left, 1=right, 2=center)

• What is returned….• AX = button status• BX = button press counter• CX = X-coordinate of last button press• DX = Y-coordinate of last button press

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

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 button’s state is reset, and a second call to the function returns nothing.

Question #11

• Which INT 33h function gets button release information?

Question #11

• Which INT 33h function gets button release information?

Function 6

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.

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, 6mov bx, 1int 33hmov mouseX, CXmov mouseY, DX

Question #13

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

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

Question #14

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

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