1
0
mirror of https://github.com/cc65/cc65.git synced 2024-11-04 17:04:58 +00:00
cc65/libsrc/lynx/crt0.s
uz e654ad49eb Allow different output formats using additional linker configs. Contributed by
Karri Kaksonen.


git-svn-id: svn://svn.cc65.org/cc65/trunk@4925 b7a2c559-68d2-44c3-8de9-860c34a00d81
2011-01-26 22:14:42 +00:00

166 lines
3.2 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.)
;
.include "lynx.inc"
.export _exit
.export __STARTUP__ : absolute = 1 ; Mark as startup
.import callirq, initlib, donelib
.import zerobss
.import callmain
.import _main
.import __INTERRUPTOR_COUNT__
.import __RAM_START__, __RAM_SIZE__, __STACKSIZE__
.include "zeropage.inc"
.include "extzp.inc"
; ------------------------------------------------------------------------
; 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__ + __STACKSIZE__)
sta sp
lda #>(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
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
; If we have IRQ functions, set the IRQ vector
; as Lynx is a console there is not much point in releasing the IRQ
lda #<__INTERRUPTOR_COUNT__
beq NoIRQ1
lda #<IRQStub
ldx #>IRQStub
sei
sta INTVECTL
stx INTVECTH
cli
; Call module constructors
NoIRQ1: 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
.segment "CODE"
IRQStub:
phy
phx
pha
cld
jsr callirq
lda INTSET
sta INTRST
pla
plx
ply
rti