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Index > DOS > print random number [bad sample code]

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dreamer85



Joined: 24 Dec 2009
Posts: 3
dreamer85
it doesnt work i know im way off but im new to coding assembly, so here's the code.. however it shows no error :/

Code:
org 100h

mov al, 2ch ;get system time
mov bl, dh  ;dh = seconds
int 21h
mov ah, 2   ;print _
mov dl, bl   ;output
int 21h
mov ax,4C00h
int 21h       


erm the idea is to get the seconds from 0..99
Post 24 Dec 2009, 15:15
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LocoDelAssembly
Your code has a bug


Joined: 06 May 2005
Posts: 4633
Location: Argentina
LocoDelAssembly
Code:
org 100h

;DOS 1+ - GET SYSTEM TIME
;
;AH = 2Ch
;
;Return:
;CH = hour CL = minute DH = second DL = 1/100 seconds
mov ah, 2ch ; You was setting AL instead of AH here, so you was calling an unspecified function here
int 21h

;DOS 1+ - WRITE CHARACTER TO STANDARD OUTPUT

;AH = 02h
;DL = character to write
; BUT, we have to convert the number to ASCII first
mov al, dl
mov ah, 0
mov cl, 10
div cl

mov dh, ah
mov dl, al
add dl, '0'
mov ah, 2
int 21h

mov dl, dh
add dl, '0'
mov ah, 2
int $21

;KEYBOARD - GET KEYSTROKE
;
;AH = 00h
;
;Return:
;AH = BIOS scan code AL = ASCII character
xor ax, ax
int $16  ; Just halting execution until some key is pressed.

mov ax,4C00h
int 21h    
Post 24 Dec 2009, 15:58
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baldr



Joined: 19 Mar 2008
Posts: 1651
baldr
LocoDelAssembly wrote:
; You was setting AL instead of AH here, so you was calling an unspecified function here
Pretty well specified: ah contains 0FFh if second command line argument has invalid drive letter, zero otherwise. Unless dreamer85 supplied two parameters, second with invalid drive letter, first DOS call was... ah==0 -- terminate program. Wink
Post 24 Dec 2009, 16:10
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dreamer85



Joined: 24 Dec 2009
Posts: 3
dreamer85
jeez i have such a long way to go Sad just when i think i got the hang of something it turns out i've made a complete mess!

thx guys.
Post 24 Dec 2009, 16:16
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DOS386



Joined: 08 Dec 2006
Posts: 1901
DOS386
dreamer85 wrote:
erm the idea is to get the seconds from 0..99


Timing code (32-bit DOS) : http://board.flatassembler.net/topic.php?t=8670
Post 25 Dec 2009, 13:07
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