Re: A86: TI-86 ASM Questions...


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Re: A86: TI-86 ASM Questions...




At 10:30 PM 8/18/98 EDT, you wrote:
>
>Sorry if any of these questions are kind of stupid, but I am just starting to
>program in ASM for the TI-86. Well, here goes:
>1. Do you guys know an easy way to fill a memory loaction with zero's? (Right
>now I have a big (1024 byte) splash type screen that is empty and I use
"ldir"
>to move it into the location)

There is a rom call routine to do it _ldhlz ($437B).  HL is the address to
start at, and B is the number of bytes to fill with 0's.  If you need more
than 255 bytes (or a faster way), use this:

ld hl,MemToFill	; point to memory to fill with 0's (or whatever)
ld de,MemToFill+1	; point one byte ahead of that
ld (hl),FillValue	; FillValue is a one byte value (0)
ld bc,NumBytes	; NumBytes is how many bytes to fill
ldir			; copy FillValue from hl to hl+1, for all bytes

>2. Is there a web site or anything where I can find out how to check the
>keyboard ports instead of using "call GET_KEY", because it pauses a bit when
>you switch from pushinng one button to pushing another?

You should try Matt's site, he has all that kind of stuff:
http://www.dogtech.com/cybop/ti86/

Or, the Assembly Studio 86 help file has a chart with the bit values and
tells how to use the ports.

>3. How can you use trig tables to do multiples of sin and cos (rounded to
>nearest integer)? (like 5cos x or something) (anyone have a routine?)

BIOSERRORS posted a couple trig tables to ticalc.org in the
\86\asm\routines section.  He made them for a raycaster he was writting.

>4. I think someone asked this already, but I probably deleted the answers.
>How can you compress an image, such as a title screen pic, so it doesn't take
>up 1024 bytes?

Scabby has some compression/decompression routines called Bloat.  You can
find them in the same place as the trig tables.

Hope this helps,


--
David Phillips
mailto:electrum@tfs.net
ICQ: 13811951
AOL/AIM: Electrum32


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