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179 lines
3.4 KiB
ArmAsm
179 lines
3.4 KiB
ArmAsm
; ***
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; CC65 Lynx Library
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;
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; Originally by Bastian Schick
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; http://www.geocities.com/SiliconValley/Byte/4242/lynx/
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;
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; Ported to cc65 (http://www.cc65.org) by
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; Shawn Jefferson, June 2004
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;
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; ***
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;
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; Startup code for cc65 (Lynx version). Based on Atari 8-bit startup
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; code structure. The C stack is located at the end of the RAM memory
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; segment and grows downward. Bastian Schick's executable header is put
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; on the front of the fully linked binary (see EXEHDR segment.)
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;
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.include "lynx.inc"
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.export _exit
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.export __STARTUP__ : absolute = 1 ; Mark as startup
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.import callirq, initlib, donelib
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.import zerobss
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.import callmain
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.import _main
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.import __BSS_LOAD__
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.import __INTERRUPTOR_COUNT__
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.import __RAM_START__, __RAM_SIZE__
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.include "zeropage.inc"
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.include "extzp.inc"
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; ------------------------------------------------------------------------
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; EXE header (BLL header)
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.segment "EXEHDR"
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.word $0880
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.dbyt __RAM_START__
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.dbyt __BSS_LOAD__ - __RAM_START__ + 10
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.byte $42,$53
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.byte $39,$33
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; ------------------------------------------------------------------------
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; Mikey and Suzy init data, reg offsets and data
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.rodata
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SuzyInitReg: .byte $28,$2a,$04,$06,$92,$83,$90
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SuzyInitData: .byte $7f,$7f,$00,$00,$24,$f3,$01
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MikeyInitReg: .byte $00,$01,$08,$09,$20,$28,$30,$38,$44,$50,$8a,$8b,$8c,$92,$93
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MikeyInitData: .byte $9e,$18,$68,$1f,$00,$00,$00,$00,$00,$ff,$1a,$1b,$04,$0d,$29
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; ------------------------------------------------------------------------
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; Actual code
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.segment "STARTUP"
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; set up system
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sei
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cld
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ldx #$FF
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txs
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; init bank switching
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lda #$C
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sta MAPCTL ; $FFF9
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; disable all timer interrupts
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lda #$80
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trb TIM0CTLA
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trb TIM1CTLA
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trb TIM2CTLA
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trb TIM3CTLA
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trb TIM5CTLA
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trb TIM6CTLA
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trb TIM7CTLA
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; disable TX/RX IRQ, set to 8E1
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lda #%11101
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sta SERCTL
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; clear all pending interrupts
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lda INTSET
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sta INTRST
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; setup the stack
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lda #<(__RAM_START__ + __RAM_SIZE__)
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sta sp
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lda #>(__RAM_START__ + __RAM_SIZE__)
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sta sp+1
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; Init Mickey
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ldx #.sizeof(MikeyInitReg)-1
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mloop: ldy MikeyInitReg,x
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lda MikeyInitData,x
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sta $fd00,y
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dex
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bpl mloop
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; these are RAM-shadows of read only regs
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ldx #$1b
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stx __iodat
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dex ; $1A
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stx __iodir
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ldx #$d
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stx __viddma
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; Init Suzy
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ldx #.sizeof(SuzyInitReg)-1
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sloop: ldy SuzyInitReg,x
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lda SuzyInitData,x
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sta $fc00,y
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dex
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bpl sloop
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lda #$24
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sta __sprsys
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; Clear the BSS data
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jsr zerobss
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; If we have IRQ functions, set the IRQ vector
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; as Lynx is a console there is not much point in releasing the IRQ
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lda #<__INTERRUPTOR_COUNT__
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beq NoIRQ1
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lda #<IRQStub
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ldx #>IRQStub
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sei
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sta INTVECTL
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stx INTVECTH
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cli
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; Call module constructors
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NoIRQ1: jsr initlib
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; Push arguments and call main
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jsr callmain
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; Call module destructors. This is also the _exit entry.
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_exit: jsr donelib ; Run module destructors
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; Endless loop
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noret: bra noret
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.segment "CODE"
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IRQStub:
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phy
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phx
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pha
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cld
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jsr callirq
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lda INTSET
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sta INTRST
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pla
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plx
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ply
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rti
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