CODEWITHSUNDEEP
assemblyx86-16dosbox
bn12
bn12

Reputation: 75

bug writing colored text in assembly (8086) int 10h\ah =9

I face a strange bug in assembly (8086) while using dosbox. I am trying to print text, colored green. this is my main, when i called the function:

mov bl,2h                       ; set the color (green)
mov dx,OFFSET str_msg           ; set the string to print
call WRITE_TEXT_IN_COLOR
call NEW_LINE

and this is the function WRITE_TEXT_IN_COLOR

proc WRITE_TEXT_IN_COLOR 
mov ah,9  
mov cx,200  ; number of chars that will be painted
int 10h
int 21H 
ret
endp WRITE_TEXT_IN_COLOR

now, when i run the program, it's print the 'required' text, along with a long strig of 'dddddd' i will really appreciate possible solutions.

Upvotes: 1

Views: 1484

Answers (1)

Fifoernik
Fifoernik

Reputation: 9899

Your code can work if the count in CX is exactly equal to the actual length of the message. If CX has a number larger than the length of the message then BIOS will display the excess in whatever character code was in the AL register (that you forgot to setup)

I propose the following changes

mov bx,0002h          ; set the color (green) AND select page 0
mov dx,OFFSET str_msg ; set the string to print
call WRITE_TEXT_IN_COLOR
call NEW_LINE

and

proc WRITE_TEXT_IN_COLOR 
 mov ax,0920h  ;AH=Function number AL=Space character  
 mov cx,200  ; number of chars that will be painted
 int 10h     ;BIOS function 09h
 int 21H     ;DOS function 09h
 ret
endp WRITE_TEXT_IN_COLOR

Upvotes: 1

Related Questions