mirror of
https://github.com/cc65/cc65.git
synced 2024-11-12 07:07:19 +00:00
99 lines
2.0 KiB
ArmAsm
99 lines
2.0 KiB
ArmAsm
; ***
|
|
; CC65 Lynx Library
|
|
;
|
|
; Originally by Bastian Schick
|
|
; http://www.geocities.com/SiliconValley/Byte/4242/lynx/
|
|
;
|
|
; Ported to cc65 (http://www.cc65.org) by
|
|
; Shawn Jefferson, June 2004
|
|
;
|
|
; This version by Karri Kaksonen, December 2010
|
|
;
|
|
; Helper stuff for the cartridge file functions. This version can deal
|
|
; with 1024 bytes/block carts that are using CART0 as a read strobe.
|
|
; Also the default crt0.s supports this most common Lynx cart format.
|
|
|
|
.include "lynx.inc"
|
|
.include "extzp.inc"
|
|
.export lynxskip0, lynxread0
|
|
.export lynxblock
|
|
.import __BLOCKSIZE__
|
|
|
|
.code
|
|
|
|
;**********************************
|
|
; Skip bytes on bank 0
|
|
; X:Y count (EOR $FFFF)
|
|
;**********************************
|
|
lynxskip0:
|
|
inx
|
|
bne @0
|
|
iny
|
|
beq exit
|
|
@0: jsr readbyte0
|
|
bra lynxskip0
|
|
|
|
;**********************************
|
|
; Read bytes from bank 0
|
|
; X:Y count (EOR $ffff)
|
|
;**********************************
|
|
lynxread0:
|
|
inx
|
|
bne @1
|
|
iny
|
|
beq exit
|
|
@1: jsr readbyte0
|
|
sta (_FileDestPtr)
|
|
inc _FileDestPtr
|
|
bne lynxread0
|
|
inc _FileDestPtr+1
|
|
bra lynxread0
|
|
|
|
;**********************************
|
|
; Read one byte from cartridge
|
|
;**********************************
|
|
readbyte0:
|
|
lda RCART0
|
|
inc _FileBlockByte
|
|
bne exit
|
|
inc _FileBlockByte+1
|
|
bne exit
|
|
|
|
;**********************************
|
|
; Select a block
|
|
;**********************************
|
|
lynxblock:
|
|
pha
|
|
phx
|
|
phy
|
|
lda __iodat
|
|
and #$fc
|
|
tay
|
|
ora #2
|
|
tax
|
|
lda _FileCurrBlock
|
|
inc _FileCurrBlock
|
|
sec
|
|
bra @2
|
|
@0: bcc @1
|
|
stx IODAT
|
|
clc
|
|
@1: inx
|
|
stx SYSCTL1
|
|
dex
|
|
@2: stx SYSCTL1
|
|
rol
|
|
sty IODAT
|
|
bne @0
|
|
lda __iodat
|
|
sta IODAT
|
|
stz _FileBlockByte
|
|
lda #<($100-(>__BLOCKSIZE__))
|
|
sta _FileBlockByte+1
|
|
ply
|
|
plx
|
|
pla
|
|
|
|
exit: rts
|
|
|