Vlad Pylin wrote:
> I want a cartridge 256K with 128 banks of 2K each.
> I know that the upper 2K of the address space is the last 2K of the ROM
and
> the lower 2K is the selectable bank. Writing to 003Fh selects this bank.
It
> is possible to access the TIA at 0040-007fh though (instead of the usual
> 0000-003fh).
>
> Please, write me how can I use it in my code and compile with DASM,
because
> I don't find that in the archives.
>
processor 6502
include "VCS3F.h"
;;
;; This lives in Bank 0..
;;
SEG
ORG $00000 ; < Bank starts at 0k in ROM
RORG $F000
somedata:
.byte 1,2,3,4,5,6,7,8
;; This lives in Bank 2..
SEG
ORG $00800 ; < Bank starts at 2K in ROM
RORG $F000
somecode:
rts
;;
;; This lives in Bank 64..
;;
SEG
ORG $20000 ; < Bank start at 128K in ROM
RORG $F000
somemorecode:
inx
stx COLUBK
jmp somemorecode
;;
;; This lives in Bank 96..
;;
SEG
ORG $30000 ; < Bank start at 192K in ROM
RORG $F000
somemorecode:
inx
stx COLUBK
jmp somemorecode
;;
;; The boot/constant bank at $F800 which lvies in Bank 127
;;
SEG
ORG $3F800
RORG $F800
RESET:
;;
;; Bank in bank 64 in $F000
;;
lda #$20000/$0800
sta $3F
jsr somemorecode
;;
;; Bank in Bank 1 into $F000
;;
lda #$0800/$0800
sta $3F
lda SomeData from bank
ORG $3FFFA
.word RESET
.word RESET
.word RESET
That's just about the way ti works..
SEG
ORG $??000
RORG $F000
Are your friends :)
andym
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