Re: A83: Question


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Re: A83: Question





In a message dated 12/06/98 1:26:38 AM, matthews@tkb.att.ne.jp writes:

>> 1. (pencol) & (penrow), Which is X and which is Y?
>
>Column...so x.
>Row......so y.

Ok, I thought I knew that, but do certain commands switch it? :\  Like the
'_vputs' routine, I've been confused by before, and it uses opposite
coordinates than the line routines, even though they dont use (pencol) and
(penrow)... =P

>> 2. Doing this...
>> 	ld hl, X*256+Y	;Is the 'h' loaded with X, and 'l' loaded with Y?
>> 	ld (pencol), hl	;But now 'l' is at (pencol)?  LSB or something?
>
>Nah, to move X over to h you must multiply it by 100h right?  100h = 256d.

Same thing, Right?  I use 256 cuz Most other people do... =P And Im pretty
sure thats the correct syntax for loading a 16 bit num in one step.  Oh ya,
'In Decimal', is probably the keyword there, thats why it is 256. I was just
keeping consistent in number bases because I wouldnt come out with my screen
coordinates in Hex... =P

>H would go into pencol, and l to penrow...wait, I think you'd do:
> 	ld (penrow),hl
>
>HTH,
>James.

Dude, that just confused the hell out of me...  I was under the impression
that the 'reverse byte loading' happens here, and involves MSB and LSB like
so...

pencol = 8252h / penrow = 8253h
ld (pencol), hl		;Now, 'l' is at 8252 and 'h' is at 8253...?

															--Jason K.