mirror of
https://github.com/cc65/cc65.git
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214 lines
3.3 KiB
ArmAsm
214 lines
3.3 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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;
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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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.constructor initsp,26
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.import getargs, argc, argv
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.import initlib, donelib
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.import zerobss, pushax
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.import _main,__filetab,getfd
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.import __CODE_LOAD__, __BSS_LOAD__
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.include "atari.inc"
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; ------------------------------------------------------------------------
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; Define and export the ZP variables for the runtime
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.exportzp sp, sreg, regsave
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.exportzp ptr1, ptr2, ptr3, ptr4
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.exportzp tmp1, tmp2, tmp3, tmp4
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.exportzp fntemp, regbank, zpspace
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.zeropage
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zpstart = *
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sp: .res 2 ; Stack pointer
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sreg: .res 2 ; Secondary register/high 16 bit for longs
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regsave: .res 2 ; slot to save/restore (E)AX into
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ptr1: .res 2
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ptr2: .res 2
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ptr3: .res 2
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ptr4: .res 2
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tmp1: .res 1
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tmp2: .res 1
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tmp3: .res 1
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tmp4: .res 1
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fntemp: .res 2 ; Pointer to file name
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regbank: .res 6 ; 6 byte register bank
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zpspace = * - zpstart ; Zero page space allocated
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.code
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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 __CODE_LOAD__
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.word __BSS_LOAD__ - 1
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.code
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.reloc
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; ------------------------------------------------------------------------
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; Actual code
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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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lda MEMTOP
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sta APPMHI ; initialize our APPMHI value
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ldx MEMTOP+1
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stx APPMHI+1
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; Call module constructors
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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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lda #0
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sta 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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sta SHFLOK
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; Initialize conio stuff
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lda #$FF
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sta CH
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; set stdio stream handles
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lda #0
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jsr getfd
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sta __filetab ; setup stdin
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lda #0
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jsr getfd
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sta __filetab + 2 ; setup stdout
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lda #0
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jsr getfd
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sta __filetab + 4 ; setup stderr
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; Pass command line if present
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jsr getargs
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lda argc
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ldx argc+1
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jsr pushax ; argc
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lda #<argv
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ldx #>argv
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jsr pushax ; 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: jsr donelib ; Run module destructors
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; Restore system stuff
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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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; Back to DOS
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rts
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; *** end of main startup code
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; setup sp
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initsp:
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lda APPMHI
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sta sp
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lda APPMHI+1
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sta sp+1
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rts
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.data
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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 $02E0
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.word $02E1
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.word __CODE_LOAD__ + 1
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