[A86] Re: The f'n 86 screen
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[A86] Re: The f'n 86 screen
I _think_ you read bit 1 of port 3 to see if the
screen update is in progress and leave the interuppt
if it is (if bit 1 is set).
This code is from Dux Gregis' Blitzgry IM2 4-Level
Grey-scale routine. This is only a snippit; the full
code can be found here:
http://guide.ticalc.org/advanced/gray.htm
and here.
http://www.ti-programmers.com/cgi-
bin/ultimatebb.cgi?ubb=get_topic&f=4&t=000001
(different explainations)
...
int_start:
ex af,af' ;its im2
exx ;
in a,(3) ;read port 3 (lcd,on key pressed port)
bit 1,a ;if bit 1 set (equal to 1)
jr z,leave_int ;leave interuppt
...
Can anyone confirm or deny this?
Ricky Cobb
http://www.tiparadise.f2s.com/
arcadesdude@operamail.com
icq 41440378
---------------------------------------------------
10/1/01 4:07:54 PM, "Andreas Finne"
<a_finne@hotmail.com> wrote:
>
>So, how do you know when the vertical refresh is
ready? And why does it only
>happen at a horisontal line about 2 pixels wide?
>
>
>----Original Message Follows----
>From: "David Phillips" <david@acz.org>
>Reply-To: assembly-86@lists.ticalc.org
>To: <assembly-86@lists.ticalc.org>
>Subject: [A86] Re: The f'n 86 screen
>Date: Mon, 1 Oct 2001 12:49:59 -0700
>
>
>This is caused by not waiting for the vertical
refresh before updating the
>screen, and erasing the sprite again before it's
ever actually displayed.
>
> > I've actually come across this problem also. The
first real game I made
>to
> > the 86 used a sprite routine by Movax. It worked
great, but when I
>crossed
>a
> > certain horisontal line on the screen, the
sprite went
>"semi-transparent".
> > If I then started going horisontally along this
line, the problem
>remained.
> > If you want to see this problem in action, and
don't mind downloading a
> > crappy game, you can get it from
www.ticalc.org/pub/86/asm/bolldin.zip
>
>
>
>
>
>
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