Previous | Next
| From: indi (all posts)
Date: 1998-06-02
Subject: Re: New questions...
|
>It has to fetch the same amount of bytes, so it remains the same.
>Bitmap mode is only different from char mode in two ways. First the
>interpretation of the screen attribute bytes differ ($0800, & $0c00),
>and the address generation for the bitmap differs. It's possible,
>that $ff1a-$ff1b is used in generating these addresses.
Okay... thought so... I'll have to play with $ff1a-1b and see what happens, also ff1f.. that may also have an effect.
>>2) Can someone do a table of volume translations from the plus 4
>>digiconvertor values into a zero to one value. This would help LOADS!
>If bit 7 is set: (if it's not set that means normal ops)
>x = low nybble (bit 0..3)
>mul = 0 if both bit 4 and bit 5 is not set
>mul = 1 if either bit 4 or bit 5 is set
>mul = 2 if both bit 4 and bit 5 is set
>alg:
> if (x>8) x=8;
> value = mul*x/16;
This looks similar to what Im doing... but I'll check and see...
>>3) What is the FIRST "FF1E" value on a new scan line, that is from
>>when the TED table starts.. i.e.
>>
>>FastModeDMA
>>pppp-*-*-*-SFSFSFSFSF... etc.
>>
>>What is the value at the first "p" - I "think" it should be "$D0"..
>>but Im not sure..
>It is $C4.
Where did you get this number from... just checking on a real plus/4
of from the C= docs? Theres nothing that "really" matchs C4... But the HSync stops at C3... Not that Im disagreeing... the numbers I played with were close to this, and This along with CPU internal cycles should help... :-)
Mike
^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^
Mike Dailly mike@scotch.demon.co.uk http://www.scotch.demon.co.uk
(Please remove the <REMOVE_ME> from my e-mail address when replying)
|
| |
Copyright © Plus/4 World Team, 2001-2024 |
