BLITTER-MFM-CODER V.1.0
DOC
by CRUNCHER/ACUME
(c)'92 by ACUME
Release Date 30/4/92
This Utility could be used to code files to an format,which is necessary
for decoding datas,which are loaded with an own Trackloader.These Datas
can be decoded EASY AND FAST with the BLITTER ! But the Datas must be
saved in the MFM-Format on Disk before decoding !
I'll give the instruction how to decode the datas in your own sourcecode.
Example:
The Datas before coding in BLITTER-MFM Format :
%01100111010110001100101011110000
The Datas in BLITTER-MFM Format :
%0 1 0 1 0 0 1 0 1 0 1 1 1 1 0 0 ; All Even bits are linked together and
% 1 0 1 1 1 1 0 0 1 0 0 0 1 1 0 0 ; All Odd bits are linked together
=
%0101001010111100 1011110010001100
EVEN ODD
To decode it,you use the Blitter :
Set the EVEN Datas in BLITTER-A ADDRESS (BLTAPT )
Set the ODD Datas in BLITTER-B ADDRESS (BLTBPT )
Set BLITTER-C DATA to %1010101010101010 (BLTCDAT)
Set the Destination Address in BLITTER-D ADDRESS (BLTDPT )
Turn on A,B,D BLITTER-CHANNELS ON (BLTCON0)
Turn off C BLITTER-CHANNELS OFF (BLTCON0)
Set Shift of B on 1 (BLTCON1)
Set Shift of A on 0 (BLTCON0)
Set Modulos A,B,D on 0 (BLTxMOD)
Set Term %11011000 (BLTCON0)
Set A-Masks on $ffff (BLTAxWM)
Set Size correct to the file,if the datas are too long for one blit,
start the blitter some more times !
move.l #EvenAdr,$dff050
move.l #OddAdr,$dff04c
move.l #DestAdr,$dff066
move.w #%1010101010101010,$dff070
clr $dff064
clr $dff062
clr $dff066
move.w #%0000110111011000,$dff040
move.w #%1000000000000000,$dff042
move.w #$ffff,$dff044
move.w #$ffff,$dff046
move.w Size,$dff058
So thats it ! If there is a big bug or do you have problems , contact me !
CRUNCHER/ACUME (Coder,Gfx)
Daniel Adler
Beethovenstr.6
3400 Goettingen
+49(0)551-44623
Contact me also for swapping LEGAL stuff,friendship,cool chats !
Greetinx to EQUI,SIR,ROLLI,ROGER WILCO,DRAGON,HARDBALL,RED KNIGHT,NOX,SMASH
ALL OTHER ACUME MEMBERS AND ALL OTHER CONTACTS !!!!!!!!!!!!!!!!
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