Re: A85: Scrolling

To: assembly-85@lists.ticalc.org
Subject: Re: A85: Scrolling
From: Humberto Yeverino <humberto@engr.csufresno.edu>
Date: Fri, 7 Aug 1998 23:56:36 -0700 (PDT)
Delivered-To: assembly-85-outgoing@towerguard.unix.edu.sollentuna.se
In-Reply-To: <cc3249c2.35ca392d@aol.com>
Reply-To: assembly-85@lists.ticalc.org

On Thu, 6 Aug 1998 CashOnly@aol.com wrote:
> 
> Does anyone have a routine that will scroll the screen left 8 pixels? In other
> words, moves each block one to the left. I am pretty sure I need to use rl,
> but I can't get it to work. I hope someone will decide to give me a response,
> this list has just been ignoring any real questions lately IMHO.
> 

Do you want it to be blank in the last column?
Anyways, the easiest way is just to copy the bytes.

ld de,FC00 ; copy to 1st byte of video memory
ld hl,FC01 ; from 2nd byte of video memory
ld bc,1023
ldir

Now the last 8 pixels on the right can be written over.

You can do the same to scroll right just swap some numbers:

ld de,FC01
ld hl,FC00
ld bc,1023
ldir

I think someone already gave a similar answer but just try these two
routines, I think it's exactly what you wanted.

-Humberto Yeverino Jr.

"I kick ass for the Lord."

http://www.engr.csufresno.edu/~humberto/Home.html
humberto@engr.csufresno.edu

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References:

A85: Scrolling

From: CashOnly@aol.com