I'm using TASM (16bit .exe) for this.
I'm trying to integrate the 18.2 timer into my assembly code and it is exhibiting some weird behavior.
Basically what I'm doing is this, I have a main procedure that sets up the timer, which I'm sure is being called.
I have the following globals:
X dw 11
timerIntSeg dw 1
timerIntOffset dw 1
The timer set up code:
push ds
push cs
pop ds
;Get the user defined timer interupt vector
mov ax, 351Ch
int 21h
mov timerIntSeg, es
mov timerIntOffset, bx
;Set it to the demo timer
mov ah, 25h
mov dx, OFFSET timerInt
int 21h
pop ds
Again, the timer is being called.
The main procedure code:
mov bx,X
mov ah,6
mov dl,bl
int 21h
xor ax,ax ; function 00h - get a key
int 16h ; call BIOS service
mov bx,X
mov ah,6
mov dl,bl
int 21h
xor ax,ax ; function 00h - get a key
int 16h ; call BIOS service
And the end of the main procedure where the timer is reset/called:
END_PROGRAM:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Reset the timer interrupt ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
mov ax, 251Ch
mov dx, timerIntOffset
mov bx, timerIntSeg
mov ds, bx
int 21h
mov ax,4C00h ; exit to DOS
int 21h
;Here is where we redraw and check if escape has been pressed
timerInt:
mov bx,X
mov ah,6
mov dl,bl
int 21h
inc X
endTimer:
iret
main endp
As you can see, the program should do the following:
print X (11, or the male sign) - this works
wait for keypress
print X
wait for keypress
exit
Those steps work. However, during this, the timer should print out x (which it sort of does), and then increment x.
What is really happening:
X prints as character 11
The timer prints the characters, starting from 0 (null) and incrementing, then at keypress character 11 is printed again, then the timer prints out continuing from the last character it printed. Textually:
11 0 1 2 3 4 5 6 (keypress)11 7 8 9 10 11 12 (keypress)(exit)
Any ideas on this? Is x treated as a local variable or something like that?
[Edited by - kordova on September 29, 2004 9:53:01 PM]
