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cc65/libsrc/lynx/crt0.s
Oliver Schmidt d8c31cf1d3 Renamed RAM to MAIN for all disk based targets.
The name RAM doesn't make much sense in general for a memeory area because i.e. the zero page is for sure RAM but is not part of the memory area named RAM.

For disk based targets it makes sense to put the disk file more into focus and here MAIN means the main part of the file - in contrast to some header.

Only for ROM based targets the name RAM is kept as it makes sense to focus on the difference between RAM and ROM.
2016-03-07 01:28:55 +01:00

137 lines
3.1 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 the 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.)
;
.export _exit
.export __STARTUP__ : absolute = 1 ; Mark as startup
.import initlib, donelib
.import zerobss
.import callmain
.import _main
.import __MAIN_START__, __MAIN_SIZE__, __STACKSIZE__
.include "zeropage.inc"
.include "extzp.inc"
.include "lynx.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,$29
; ------------------------------------------------------------------------
; Actual code
.segment "STARTUP"
; Set up the system.
sei
cld
ldx #$FF
txs
; Init the 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 the TX/RX IRQ; set to 8E1.
lda #%11101
sta SERCTL
; Clear all pending interrupts.
lda INTSET
sta INTRST
; Set up the stack.
lda #<(__MAIN_START__ + __MAIN_SIZE__ + __STACKSIZE__)
ldx #>(__MAIN_START__ + __MAIN_SIZE__ + __STACKSIZE__)
sta sp
stx 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
cli
; Clear the BSS data.
jsr zerobss
; Call the module constructors.
jsr initlib
; Push the command-line arguments; and, call main().
jsr callmain
; Call the module destructors. This is also the exit() entry.
_exit: jsr donelib ; Run module destructors
; Endless loop
noret: bra noret