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cc65/libsrc/lynx/crt0.s
cuz 84be744418 Moved additional zeropage variables into an extra module.
Added interrupt vector to joystick driver.
New code from Karri.
Rewrote joystick initialization to make it somewhat shorter.


git-svn-id: svn://svn.cc65.org/cc65/trunk@3281 b7a2c559-68d2-44c3-8de9-860c34a00d81
2004-11-06 13:51:02 +00:00

153 lines
3.0 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
;
; ***
;
; Startup code for cc65 (Lynx version). Based on Atari 8-bit startup
; code structure. The C stack is located at the end of the RAM memory
; segment and grows downward. Bastian Schick's executable header is put
; on the front of the fully linked binary (see EXEHDR segment.)
;
; This must be the *first* file on the linker command line
;
.include "lynx.inc"
.export _exit
.import initlib, donelib
.import zerobss
.import callmain
.import _main
.import __BSS_LOAD__
.import __RAM_START__, __RAM_SIZE__
.include "zeropage.inc"
.include "extzp.inc"
; ------------------------------------------------------------------------
; EXE header (BLL header)
.segment "EXEHDR"
.word $0880
.dbyt __RAM_START__
.dbyt __BSS_LOAD__ - 1
.byte $42,$53
.byte $39,$33
; ------------------------------------------------------------------------
; Mikey and Suzy init data, reg offsets and data
.rodata
SuzyInitReg: .byte $28,$2a,$04,$06,$92,$83,$90
SuzyInitData: .byte $7f,$7f,$00,$00,$24,$f3,$01
MikeyInitReg: .byte $00,$01,$08,$09,$20,$28,$30,$38,$44,$50,$8a,$8b,$8c,$92,$93
MikeyInitData: .byte $9e,$18,$68,$1f,$00,$00,$00,$00,$00,$ff,$1a,$1b,$04,$0d,$29
; ------------------------------------------------------------------------
; Actual code
.segment "STARTUP"
; set up system
sei
cld
ldx #$FF
txs
; init bank switching
lda #$C
sta MAPCTL ; $FFF9
; disable all timer interrupts
lda #$80
trb TIM0CTLA
trb TIM1CTLA
trb TIM2CTLA
trb TIM3CTLA
trb TIM5CTLA
trb TIM6CTLA
trb TIM7CTLA
; disable TX/RX IRQ, set to 8E1
lda #%11101
sta SERCTL
; clear all pending interrupts
lda INTSET
sta INTRST
; setup the stack
lda #<(__RAM_START__ + __RAM_SIZE__)
sta sp
lda #>(__RAM_START__ + __RAM_SIZE__)
sta sp+1
; Init Mickey
ldx #.sizeof(MikeyInitReg)-1
mloop: ldy MikeyInitReg,x
lda MikeyInitData,x
sta $fd00,y
dex
bpl mloop
; these are RAM-shadows of read only regs
ldx #$1b
stx __iodat
dex ; $1A
stx __iodir
ldx #$d
stx __viddma
; Init Suzy
ldx #.sizeof(SuzyInitReg)-1
sloop: ldy SuzyInitReg,x
lda SuzyInitData,x
sta $fc00,y
dex
bpl sloop
lda #$24
sta __sprsys
; Clear the BSS data
jsr zerobss
; Call module constructors
jsr initlib
; Push arguments and call main
jsr callmain
; Call module destructors. This is also the _exit entry.
_exit: jsr donelib ; Run module destructors
; Endless loop
noret: bra noret