Commodore Amiga - Page 206

LABELl:
MOVE.W
AND.W
BEQ.S
LABEL2:
SWAP
BEQ.S
LOOP:
BSR
MOVE
DONE:
RTS
Note:
#$FFCO,Dl
DO,Dl
the upper word of d1 is already zero
jNow look at more upper bits
jExtract 10 more bits
LABEL2
SUB.L
BSR
MOVE.W
DO
DONE
CLR.W
WAITBLIT
Dl,DO
WAITBLIT
DO,BLTSIZE(Al)
Dl
jAny to do?
jHow
many 128-Kbyte blocks left
i Wait for any previous blit to complete
i Trigger next blit
iGheck for any bits
set in upper word
j Will do blits 128 Kbytes at a time
Need move for this to work on 68000
Dl,BLTSIZE(Al) iTrigger a big blit
SUBQ.W #1,DO iGould be a dbf
BNE.S LOOP iAny more 128-Kbyte blits?
Exit. Note: blit
may still be in progress.
The support to manage async blits is one
of the
reasons to use the
system software from Amiga.
194 Blitter Hardware