Edit - Stack Overflow

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

Required fields*

Rev

Required fields*

MASM Using ah=02h int 21h, display text, highlight with flickering + inverse display

As i understand. Program must clean background, display message1 ( dark letters on white background + highlighting by flickering). then go up for 2 strings and display message2(also dark letters on white background + highlighting by flickering). then go up for 2 strings and display message3(also dark letters on white background + highlighting by flickering). And it says that i need to use 02h function(but didn't says that i cant use other)

It's original task

I tried to start from display message 1 with dark letters on white background + highlighting by flickering.

stack segment para stack 'stack' ; start of stack
 db 64 dup('stack***') 
stack ends 
 
dseg segment para public 'data' ; start of data
 message1 db 'This is line 1:$'
 message2 db 'This is line 2'
 message3 db 'This is line 3' 
 Cls db 1Bh, '[2J', '$'
 cl1 db '7m'
dseg ends 
 
cseg segment para public 'code' ;start of commands
prog proc far 
 assume cs:cseg, ds:dseg, ss:stack 
 
 mov ax, dseg 
 mov ds, ax 
 mov ax,1003h
 mov bl,112
 int 10h
 
 lea dx,message1
 mov ah, 09h
 int 21h
 
 ;end of program
 mov ah, 4Ch 
 int 21h 
prog endp ; конец процедуры
cseg ends ; конец сегмента команд
 end prog ; конец программы

Answer*

[**EDIT 8 jan 2025**] Following an OP comment, I have added a MASM version of the program.

-----

The task states to use the DOS.PrintCharacter function 02h. Do note that DOS does not care about colors at all! You will have to use some BIOS function(s) to make the texts colorful and/or blinking.

On the text video screen a character can be represented in one of 16 foreground colors, and in one of 8 background colors. This accounts for 7 bits in the so-called attribute byte. The remaining 8th bit is dedicated to the blinking aspect: If that particular bit is set, then the character will blink. (This is the default mode of operating after a video mode set, but using that 1003h BIOS function we can choose to abandon the blinking capability in favor of an additional 8 background colors).

To 'clean the background' my demo program uses the 0600h BIOS function that fills the entire screen with space characters (ASCII 32) using the attribute byte that the user provides in the BH register.

The attribute byte for BlinkingBlackOnWhite is F0h = 11110000b

 7 6 5 4 3 2 1 0
 ---------------
 . . . . 0 0 0 0 <= Black foreground
 . 1 1 1 . . . . <= White background
 1 . . . . . . . <= Blinking aspect
 
Since the task dictates a certain order for displaying the messages (going up on the screen for which there's no special control code), I used the BIOS.SetCursorPosition function 02h.

Next is a .COM executable program. I have tested this FASM version in the DOSBox environment and it works allright:

```
; FASM/DOSBox version

 ORG 256

 mov ax, 0003h ; BIOS.SetVideoMode 80x25 16-color text
 int 10h
 mov dx, 184Fh ; LowerRightCorner (79,24)
 xor cx, cx ; UpperLeftCorner (0,0)
 mov bh, 0F0h ; Attribute for blinking BlackOnWhite
 mov ax, 0600h ; BIOS.ClearWindow
 int 10h
 mov si, msg
 call PrintAT ; -> SI
 call PrintAT ; -> SI
 call PrintAT ; -> SI

 mov ah, 00h ; BIOS.WaitKeystroke
 int 16h ; -> AX
 mov ax, 0003h ; BIOS.SetVideoMode 80x25 16-color text
 int 10h
 mov ax, 4C00h ; DOS.TerminateWithReturncode
 int 21h
; ----------------------
; IN (si) OUT (si)
PrintAT:
 push ax
 push bx
 push dx
 lodsw
 mov dx, ax ; DH is Row, DL is Column
 mov bh, 0 ; DisplayPage
 mov ah, 02h ; BIOS.SetCursorPosition
 int 10h

 jmp .b
.a: mov dl, al
 mov ah, 02h ; DOS.PrintCharacter
 int 21h ; -> AL
.b: lodsb
 cmp al, 0
 jne .a
 pop dx
 pop bx
 pop ax
 ret
; ----------------------
msg db 10, 14, 'Message 1', 0
 db 10, 12, 'Message 2', 0
 db 10, 10, 'Message 3', 0
```

This is a MASM version that produces an .EXE executable:

```
stack segment para stack 'stack'

 db 64 dup('stack***') 

stack ends 
; -------------------------------- 
dseg segment para public 'data'

msg db 10, 14, 'Message 1', 0
 db 10, 12, 'Message 2', 0
 db 10, 10, 'Message 3', 0

dseg ends
; -------------------------------- 
cseg segment para public 'code'

prog proc far 
 assume cs:cseg, ds:dseg, ss:stack 
 
 mov ax, dseg 
 mov ds, ax 

 mov ax, 0x0003 ; BIOS.SetVideoMode 80x25 16-color text
 int 0x10
 mov dx, 0x184F ; LowerRightCorner (79,24)
 xor cx, cx ; UpperLeftCorner (0,0)
 mov bh, 0xF0h ; Attribute for blinking BlackOnWhite
 mov ax, 0x0600 ; BIOS.ClearWindow
 int 0x10
 mov si, OFFSET msg
 call PrintAT ; -> SI
 call PrintAT ; -> SI
 call PrintAT ; -> SI

 mov ah, 0x00 ; BIOS.WaitKeystroke
 int 0x16 ; -> AX
 mov ax, 0x0003 ; BIOS.SetVideoMode 80x25 16-color text
 int 0x10
 mov ax, 0x4C00 ; DOS.TerminateWithReturncode
 int 0x21
; ----------------------
; IN (si) OUT (si)
PrintAT:
 push ax
 push bx
 push dx
 lodsw
 mov dx, ax ; DH is Row, DL is Column
 mov bh, 0 ; DisplayPage
 mov ah, 0x02 ; BIOS.SetCursorPosition
 int 0x10

 jmp .b
.a: mov dl, al
 mov ah, 0x02 ; DOS.PrintCharacter
 int 0x21 ; -> AL
.b: lodsb
 cmp al, 0
 jne .a
 pop dx
 pop bx
 pop ax
 ret
prog endp

cseg ends
; --------------------------------
end prog
```

Draft saved

Draft discarded

Edit Summary*

Cancel

i can use only masm/tasm, link/tlink,debug,td. masm name link name debug name.exe. i tried to apply your code in structure of my start program, but failed

sedvivus
– sedvivus

2025年01月07日 07:37:25 +00:00
Commented Jan 7, 2025 at 7:37
i can't insert img in comment, i tried exe version, but somehow after masm name i get: "End of file encountered on input file. name.asm(68) : error 85: End of file, no END directive." But i see that u apply end prog. i don't know why this message appears

sedvivus
– sedvivus

2025年01月08日 10:39:34 +00:00
Commented Jan 8, 2025 at 10:39
ok, i add enter before and after end prog and it helped. program display grey background + black letters + highlighting by flickering, but only message 1

sedvivus
– sedvivus

2025年01月08日 16:30:22 +00:00
Commented Jan 8, 2025 at 16:30
The call pushes the return address, two bytes (word), onto the stack. retf takes the return address from the stack, four bytes (dword).

sedvivus
– sedvivus

2025年01月08日 21:56:36 +00:00
Commented Jan 8, 2025 at 21:56

Add a comment |

How to Edit

Correct minor typos or mistakes
Clarify meaning without changing it
Add related resources or links
Always respect the author’s intent
Don’t use edits to reply to the author

How to Format

create code fences with backticks ` or tildes ~
```
like so
```
add language identifier to highlight code
```python
def function(foo):
print(foo)
```
put returns between paragraphs
for linebreak add 2 spaces at end
_italic_ or **bold**
indent code by 4 spaces
backtick escapes `like _so_`
quote by placing > at start of line
to make links (use https whenever possible)

<https://example.com>

[example](https://example.com)

<a href="https://example.com">example</a>

formatting help »
answering help »

How to Tag

A tag is a keyword or label that categorizes your question with other, similar questions. Choose one or more (up to 5) tags that will help answerers to find and interpret your question.

complete the sentence: my question is about...
use tags that describe things or concepts that are essential, not incidental to your question
favor using existing popular tags
read the descriptions that appear below the tag

If your question is primarily about a topic for which you can't find a tag:

combine multiple words into single-words with hyphens (e.g. python-3.x), up to a maximum of 35 characters
creating new tags is a privilege; if you can't yet create a tag you need, then post this question without it, then ask the community to create it for you

popular tags »

CollectivesTM on Stack Overflow

MASM Using ah=02h int 21h, display text, highlight with flickering + inverse display

Answer*