Assembly

Assembly RSS

Displaying numeric data

•

Join Date: Jul 2006

Posts: 16

Reputation: vov4ik is an unknown quantity at this point

Solved Threads: 0

vov4ik

Offline

Newbie Poster

Displaying numeric data

Jul 11th, 2006

Hi, I'm new to 80x86 Assembler...

My question is very simple one: how should i print number on screen?

I used the following code to print ascii data:

 Help with Code Tags 
 Assembly Syntax (Toggle Plain Text) 
  mov ah,09h    ;load code of print function
  lea dx, Var     ;load address of variable to be printed
  int 21h           ;DOS call 
 
..........................
Var db 'SOME_DATA','$'
  mov ah,09h    ;load code of print function
  lea dx, Var     ;load address of variable to be printed
  int 21h           ;DOS call 
 
..........................
Var db 'SOME_DATA','$'

When i needed to define numeric data, i changed this to:

 Help with Code Tags 
 Assembly Syntax (Toggle Plain Text) 
Var db 4 ; an integer to be printed
Var db 4 ; an integer to be printed

and used the same sequence to print as it was with the string data. But program printed out only unreadable set of ascii characters

What's wrong with my code?

Also,how i could print data stored in one of the registers?

Thank you in advance

•

Join Date: Jun 2005

Posts: 14

Reputation: thandermax is an unknown quantity at this point

Solved Threads: 0

thandermax thandermax is offline

Offline

Newbie Poster

Re: Displaying numeric data

Jul 12th, 2006

Var contains data which will be evaluated as ASCII , but as 4 is in deciaml it will be evaluated as ASCII value 4 , which is a nonprintable chracter.

You need to convert 4 to ASCII "4" . To convert 4 to ASCII "4" you need to add 30(deciaml) . AS in ASCII "0" starts from 30 and "9" at 39.

You need to separate each digit and change that to ASCII ( in range 30 to 39).

that is to print 17 (decimal) you have to separate 1 and 7 and change it to 1 => 31h and 7 => 37h.

And print as

•

data db 2dup(0)

mov [data],31h
mov [data+1],37h
lea dx,data
mov ah,09h
int 21h

•

Join Date: Jun 2005

Posts: 14

Reputation: thandermax is an unknown quantity at this point

Solved Threads: 0

thandermax thandermax is offline

Offline

Newbie Poster

Re: Displaying numeric data

Jul 12th, 2006

Separation code you need to develop .

It's easy, just mask the upper nibble(4 bit) and get lower nibble .
mask the lower nibble and shift 4 times to left and get the upper nibble.

AND the data with 0fh to mask upper nibble, and with f0h to mask lower nibble.

Hope you got the idea