2018-09-26 18:01:14 +00:00
|
|
|
|
|
|
|
|
|
|
|
|
|
Memory Map:
|
|
|
|
|
$0000-$0100 = ZERO PAGE
|
|
|
|
|
$0100-$0200 = STACK
|
|
|
|
|
$0400-$0800 = TEXT/GR PAGE0
|
|
|
|
|
$0800-$0C00 = TEXT/GR PAGE1
|
|
|
|
|
$0C00-$0fff = we use this as TEXT/GR offscreen buffer
|
|
|
|
|
$1000-$1fff = 4k free
|
|
|
|
|
$2000-$3fFF = HGR1 page ; note we never use HGR2 ($4000-$6000)
|
|
|
|
|
$4000-$9600 = roughly 20k(?)
|
|
|
|
|
$9600-$BFFF = DOS3.3
|
|
|
|
|
$C000-$FFFF = peripherals/ROM
|
|
|
|
|
|
2018-10-02 04:32:57 +00:00
|
|
|
Largest can load from $4000 to $9600 = 22,016
|
|
|
|
|
Largest can load from $1000 to $9600 = 34,304
|
|
|
|
|
$4000-$C000 = 32768
|
2018-09-29 17:24:13 +00:00
|
|
|
|
|
|
|
|
|
|
|
|
|
C64:
|
|
|
|
|
Apple II:
|
|
|
|
|
Starring:
|
|
|
|
|
Three pages page flipping. Hires colors subset of Lores so
|
|
|
|
|
can replicate a blocky color image. Could in theory animate this
|
|
|
|
|
at 60Hz. Also could flip between 4 pages, but need the 8k of
|
|
|
|
|
HGR page2.
|
|
|
|
|
|
2018-10-01 03:07:57 +00:00
|
|
|
For cycle-counting timing, jmp one into a bit $C055 instruction
|
|
|
|
|
which is EOR $C0,X (4 cycles)
|
|
|
|
|
|
2018-10-01 05:34:41 +00:00
|
|
|
Note, discover that the LORES and HIRES pages aren't exact matches
|
|
|
|
|
for each other, even when using same color. Half-pixel off?
|
|
|
|
|
|
2018-09-29 17:24:13 +00:00
|
|
|
E-mail:
|
|
|
|
|
Half screen text, half 40x96 lores.
|
|
|
|
|
Text is also interlaced top/bottom to create new chars (including
|
|
|
|
|
some lowercase) on Apple II+ and before w/o lower case.
|
|
|
|
|
Trouble as the built-in font is offset a frame on II vs IIe?
|
|
|
|
|
Also annoyance, my GR compressor uses Grey2 (color $a) as encoding,
|
|
|
|
|
which means can't use a GR image to hold plain black spaces (char $a0)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
