Hi
I'm after a good m/c routine to scroll pmode1 left/right, quite happy with 8 bit shift, but any would do.
Also m/c routine to do the same with the text screen.
If there is an article in a NDUG or up2date, even DU, then please point me in that direction.
Thanks
M/C routine for screen scroll
Re: M/C routine for screen scroll
At its very simplest:
Substitute text labels for the numeric back-referenced labels if your assembler won't do those.
For text mode, start=$0400, end=$0600. For PMODE1, start=$0600, end=$1200 (add $0600 to both if DOS is attached).
This can be made a *lot* faster with some additional complexity (or a *lot* slower if you want to scroll anything less than a byte at a time).
Code: Select all
left ldx #start
1 ldd 1,x
std ,x++
cmpx #end
blo 1B
rts
right ldx #end
1 ldd -3,x
std ,--x
cmpx #start
bhi 1B
rts
For text mode, start=$0400, end=$0600. For PMODE1, start=$0600, end=$1200 (add $0600 to both if DOS is attached).
This can be made a *lot* faster with some additional complexity (or a *lot* slower if you want to scroll anything less than a byte at a time).
Re: M/C routine for screen scroll
Superb
Having fun with this already
Cheers
Having fun with this already
Cheers