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https://github.com/cc65/cc65.git
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142 lines
4.2 KiB
ArmAsm
142 lines
4.2 KiB
ArmAsm
;
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; Startup code for cc65 (PCEngine version)
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;
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; by Groepaz/Hitmen <groepaz@gmx.net>
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; based on code by Ullrich von Bassewitz <uz@cc65.org>
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;
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; This must be the *first* file on the linker command line
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;
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.export _exit
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.export __STARTUP__ : absolute = 1 ; Mark as startup
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.import initlib, donelib
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.import push0, _main, zerobss
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.import initheap
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.import IRQStub
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; Linker generated
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.import __RAM_START__, __RAM_SIZE__
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.import __ROM0_START__, __ROM0_SIZE__
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.import __ROM_START__, __ROM_SIZE__
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.import __STARTUP_LOAD__,__STARTUP_RUN__, __STARTUP_SIZE__
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.import __CODE_LOAD__,__CODE_RUN__, __CODE_SIZE__
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.import __RODATA_LOAD__,__RODATA_RUN__, __RODATA_SIZE__
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.import __DATA_LOAD__,__DATA_RUN__, __DATA_SIZE__
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.import __BSS_SIZE__
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.include "pce.inc"
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.include "extzp.inc"
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.importzp sp
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.importzp ptr1,ptr2
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.importzp tmp1,tmp2,tmp3
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; ------------------------------------------------------------------------
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; Place the startup code in a special segment.
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.segment "STARTUP"
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start:
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; Set up the CPU and System-IRQ
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; Initialize CPU
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sei
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nop
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csh ; Set high speed CPU mode
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nop
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cld
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nop
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; Set up stack and memory mapping
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ldx #$FF ; Stack top ($21FF)
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txs
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; At startup all MPRs are set to 0, so init them
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lda #$ff
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tam #%00000001 ; 0000-1FFF = Hardware page
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lda #$F8
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tam #%00000010 ; 2000-3FFF = Work RAM
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; FIXME: setup a larger block of memory to use with C-code
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;lda #$F7
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;tam #%00000100 ; 4000-5FFF = Save RAM
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;lda #1
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;tam #%00001000 ; 6000-7FFF Page 2
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;lda #2
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;tam #%00010000 ; 8000-9FFF Page 3
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;lda #3
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;tam #%00100000 ; A000-BFFF Page 4
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;lda #4
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;tam #%01000000 ; C000-DFFF Page 5
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;lda #0
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;tam #%10000000 ; e000-fFFF hucard/syscard bank 0
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; Clear work RAM (2000-3FFF)
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stz <$00
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tii $2000, $2001, $1FFF
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; Initialize hardware
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stz TIMER_CTRL ; Timer off
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lda #$07
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sta IRQ_MASK ; Interrupts off
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stz IRQ_STATUS ; Acknowledge timer
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; FIXME; i dont know why the heck this one doesnt work when called from a constructor :/
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.import vdc_init
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jsr vdc_init
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; Turn on background and VD interrupt/IRQ1
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lda #$05
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sta IRQ_MASK ; IRQ1=on
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; Clear the BSS data
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jsr zerobss
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; Copy the .data segment to RAM
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tii __DATA_LOAD__, __DATA_RUN__, __DATA_SIZE__
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; Set up the stack
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lda #<(__RAM_START__+__RAM_SIZE__)
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ldx #>(__RAM_START__+__RAM_SIZE__)
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sta sp
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stx sp + 1
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; Call module constructors
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jsr initlib
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cli ; allow IRQ only after constructors have run
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; Pass an empty command line
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jsr push0 ; argc
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jsr push0 ; argv
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ldy #4 ; Argument size
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jsr _main ; Call the users code
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; Call module destructors. This is also the _exit entry.
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_exit:
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jsr donelib ; Run module destructors
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; reset the PCEngine (start over)
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jmp start
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_nmi:
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rti
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.export initmainargs
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initmainargs:
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rts
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; ------------------------------------------------------------------------
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; hardware vectors
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; ------------------------------------------------------------------------
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.segment "VECTORS"
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.word IRQStub ; $fff6 IRQ2 (External IRQ, BRK)
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.word IRQStub ; $fff8 IRQ1 (VDC)
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.word IRQStub ; $fffa Timer
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.word _nmi ; $fffc NMI
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.word start ; $fffe reset
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