mirror of
https://github.com/cc65/cc65.git
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201 lines
3.2 KiB
ArmAsm
201 lines
3.2 KiB
ArmAsm
;
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; Startup code for cc65 (ATARI version)
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;
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; Contributing authors:
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; Mark Keates
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; Freddy Offenga
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; Christian Groessler
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; Stefan Haubenthal
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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 callmain, zerobss, callirq
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.import __INTERRUPTOR_COUNT__
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.import __STARTUP_LOAD__, __ZPSAVE_LOAD__
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.import __RESERVED_MEMORY__
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.include "zeropage.inc"
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.include "atari.inc"
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; ------------------------------------------------------------------------
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; EXE header
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.segment "EXEHDR"
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.word $FFFF
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.word __STARTUP_LOAD__
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.word __ZPSAVE_LOAD__ - 1
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; ------------------------------------------------------------------------
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; Actual code
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.segment "STARTUP"
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rts ; fix for SpartaDOS / OS/A+
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; they first call the entry point from AUTOSTRT and
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; then the load addess (this rts here).
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; We point AUTOSTRT directly after the rts.
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; Real entry point:
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; Save the zero page locations we need
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ldx #zpspace-1
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L1: lda sp,x
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sta zpsave,x
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dex
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bpl L1
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; Clear the BSS data
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jsr zerobss
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; Setup the stack
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tsx
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stx spsave
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; Report memory usage
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lda APPMHI
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sta appmsav ; remember old APPMHI value
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lda APPMHI+1
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sta appmsav+1
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sec
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lda MEMTOP
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sbc #<__RESERVED_MEMORY__
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sta APPMHI ; initialize our APPMHI value
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sta sp ; setup runtime stack part 1
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lda MEMTOP+1
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sbc #>__RESERVED_MEMORY__
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sta APPMHI+1
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sta sp+1 ; setup runtime stack part 2
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; If we have IRQ functions, chain our stub into the IRQ vector
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lda #<__INTERRUPTOR_COUNT__
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beq NoIRQ1
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lda VVBLKI
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ldx VVBLKI+1
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sta IRQInd+1
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stx IRQInd+2
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lda #6
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ldy #<IRQStub
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ldx #>IRQStub
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jsr SETVBV
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; Call module constructors
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NoIRQ1: jsr initlib
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; Set left margin to 0
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lda LMARGN
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sta old_lmargin
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ldy #0
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sty LMARGN
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; Set keyb to upper/lowercase mode
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ldx SHFLOK
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stx old_shflok
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sty SHFLOK
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; Initialize conio stuff
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dey ; Set X to $FF
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sty CH
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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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; Reset the IRQ vector if we chained it.
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pha ; Save the return code on stack
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lda #<__INTERRUPTOR_COUNT__
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beq NoIRQ2
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lda #6
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ldy IRQInd+1
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ldx IRQInd+2
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jsr SETVBV
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; Restore system stuff
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NoIRQ2: ldx spsave
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txs ; Restore stack pointer
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; Restore left margin
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lda old_lmargin
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sta LMARGN
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; Restore kb mode
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lda old_shflok
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sta SHFLOK
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; Restore APPMHI
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lda appmsav
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sta APPMHI
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lda appmsav+1
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sta APPMHI+1
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; Copy back the zero page stuff
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ldx #zpspace-1
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L2: lda zpsave,x
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sta sp,x
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dex
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bpl L2
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; Turn on cursor
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inx
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stx CRSINH
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; Back to DOS
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rts
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; ------------------------------------------------------------------------
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; The IRQ vector jumps here, if condes routines are defined with type 2.
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IRQStub:
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cld ; Just to be sure
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jsr callirq ; Call the functions
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jmp IRQInd ; Jump to the saved IRQ vector
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; ------------------------------------------------------------------------
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; Data
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.data
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IRQInd: jmp $0000
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; *** end of main startup code
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.segment "ZPSAVE"
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zpsave: .res zpspace
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.bss
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spsave: .res 1
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appmsav: .res 1
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old_shflok: .res 1
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old_lmargin: .res 1
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.segment "AUTOSTRT"
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.word RUNAD ; defined in atari.h
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.word RUNAD+1
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.word __STARTUP_LOAD__ + 1
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