Re: A86: Screen Offset Routine
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Re: A86: Screen Offset Routine
This is not working. As soon as it goes up once, it stops. However, it
works on my 86 emu. Strange...any suggestions?
Here's the code u sent me
-----------------------------------------------
to move down, do this:
move_down:
ld hl,$ffff-16 ;one row up
ld de,$ffff ;bottom row
ld bc,1024-16 ;all but one row
lddr
ret
to move up, do this:
move_up:
ld hl,$fc00+16
ld de,$fc00
ld bc,1024-16
ldir
ret
if you want to "shake" the screen, just run a loop alternating both
routines:
shake_screen:
ld b,100 ;do it 100 times (just an example number)
shake_loop:
push bc
call move_down
call delay
call move_up
call delay
pop bc
djnz shake_loop
ret
;added for visibility. may be unnecessary
delay:
ld b,255
delay_loop:
nop
nop
djnz delay_loop
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