flat assembler
Message board for the users of flat assembler.

Index > DOS > ScrollUp = ScrollDown ?

Author
Thread Post new topic Reply to topic
SeproMan



Joined: 11 Oct 2009
Posts: 60
Location: Belgium
SeproMan
When I'm in a text document and I want to go to the next page I have to scroll DOWN.
When the DOS prompt is at the bottom line of the screen and I push the <enter> key the screen scrolls. Is this ScrollUp or is this ScrollDown Question

In both cases what happens on the screen is exactly the same. The contents are moved upwards and a new (blank) line is displayed at the bottom. An action that video bios function 6 calls 'Scroll window up'.

I'm currently writing a manual of some kind and I would want it to be as exact as possible. Many authors circumvent this problem by never mentioning any direction!

_________________
Real Address Mode.
Post 10 Feb 2013, 14:29
View user's profile Send private message Reply with quote
revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17473
Location: In your JS exploiting you and your system
revolution
It depends upon your point of view.

Page Down ---> Screen image goes up
Scroll Down ---> Screen image goes up
Post 10 Feb 2013, 14:36
View user's profile Send private message Visit poster's website Reply with quote
JohnFound



Joined: 16 Jun 2003
Posts: 3502
Location: Bulgaria
JohnFound
When you are in text document and you want to go to the next page, you have to MOVE DOWN. But the screen in this moment SCROLL UP. The movement and the scroll are always in different directions. Note that the windows scrollbars actually accept movement commands, not scrolling commands. Moving commands are related to some caret type of element.

In the same time, there is a "panning" type of commands - used for example in PDF readers. In this case you are moving the whole document. In this case, the directions of the scrolling and panning are identical
Post 10 Feb 2013, 15:30
View user's profile Send private message Visit poster's website ICQ Number Reply with quote
DOS386



Joined: 08 Dec 2006
Posts: 1901
DOS386
> Note that the windows scrollbars actually accept movement commands, not scrolling commands

...

> When the DOS prompt is at the bottom line of the screen and I push

Are you in DOS ?

> I'm currently writing a manual

About what?

> ScrollUp = ScrollDown ?

DOS and BIOS can only scroll up. Text vanishing at screen top is lost forever.

> I want to go to the next page I have to scroll DOWN.

NO. You push PAGE_DOWN and scroll up.
Post 11 Feb 2013, 04:50
View user's profile Send private message Reply with quote
freecrac



Joined: 19 Oct 2011
Posts: 117
Location: Germany Hamburg
freecrac
But when the rows of the textscreen scrolls up, then the bios does not use a smooth-scrolling of each scan line with adjusting the start address of the row scan register inside of the CRT controller.
So i have written an example of a DOS-textviewer(16 bitmode) for the textscreen with 80 collums and 50 rows using a smooth scrolling.

Hints: The length of a textfiles should be 64 KB or lower.
The comments in the sourcefile are only written in the german language.
www.alice-dsl.net/freecracmaps/Tool/TEXT-OUT.ZIP

Dirk
Post 11 Feb 2013, 10:03
View user's profile Send private message Send e-mail Reply with quote
SeproMan



Joined: 11 Oct 2009
Posts: 60
Location: Belgium
SeproMan
So basically it comes down to the person giving a command (page down) and the screen performing an action (scroll up).
The subject of the sentence is thus all-important!
Thanks for this clarification!

DOS386 wrote:

DOS and BIOS can only scroll up. Text vanishing at screen top is lost forever.


BIOS actually has functions for both directions.
Function 6 Scroll Window up.
Function 7 Scroll Window down.
Normal DOS console operations will obviously only scroll up.

DOS386 wrote:

Are you in DOS ?

> I'm currently writing a manual

About what?


I'm kind of a DOS addict and so I'm writing a DOS-like OS which naturally needs a manual.

_________________
Real Address Mode.
Post 14 Feb 2013, 11:24
View user's profile Send private message Reply with quote
Display posts from previous:
Post new topic Reply to topic

Jump to:  


< Last Thread | Next Thread >
Forum Rules:
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Copyright © 1999-2020, Tomasz Grysztar. Also on YouTube, Twitter.

Website powered by rwasa.