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169 lines
4.9 KiB
ArmAsm
169 lines
4.9 KiB
ArmAsm
;
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; Oliver Schmidt, 2009-09-15
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;
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; Startup code for cc65 (Apple2 version)
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;
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.export done, return
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.export zpsave, rvsave, reset
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.export __STARTUP__ : absolute = 1 ; Mark as startup
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.import initlib, _exit
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.import zerobss, callmain
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.import __ONCE_LOAD__, __ONCE_SIZE__ ; Linker generated
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.import __LC_START__, __LC_LAST__ ; Linker generated
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.include "zeropage.inc"
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.include "apple2.inc"
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; ------------------------------------------------------------------------
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.segment "STARTUP"
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; ProDOS TechRefMan, chapter 5.2.1:
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; "For maximum interrupt efficiency, a system program should not
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; use more than the upper 3/4 of the stack."
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ldx #$FF
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txs ; Init stack pointer
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; Save space by putting some of the start-up code in the ONCE segment,
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; which can be re-used by the BSS segment, the heap and the C stack.
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jsr init
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; Clear the BSS data.
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jsr zerobss
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; Push the command-line arguments; and, call main().
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jmp callmain
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; ------------------------------------------------------------------------
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.segment "ONCE"
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; Save the zero-page locations that we need.
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init: ldx #zpspace-1
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: lda sp,x
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sta zpsave,x
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dex
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bpl :-
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; Save the original RESET vector.
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ldx #$02
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: lda SOFTEV,x
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sta rvsave,x
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dex
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bpl :-
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; Check for ProDOS.
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ldy $BF00 ; MLI call entry point
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cpy #$4C ; Is MLI present? (JMP opcode)
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bne basic
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; Check the ProDOS system bit map.
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lda $BF6F ; Protection for pages $B8 - $BF
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cmp #%00000001 ; Exactly system global page is protected
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bne basic
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; No BASIC.SYSTEM; so, quit to the ProDOS dispatcher instead.
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lda #<quit
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ldx #>quit
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sta done+1
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stx done+2
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; No BASIC.SYSTEM; so, use the addr of the ProDOS system global page.
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lda #<$BF00
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ldx #>$BF00
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bne :+ ; Branch always
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; Get the highest available mem addr from the BASIC interpreter.
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basic: lda HIMEM
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ldx HIMEM+1
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; Set up the C stack.
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: sta sp
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stx sp+1
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; ProDOS TechRefMan, chapter 5.3.5:
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; "Your system program should place in the RESET vector the
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; address of a routine that ... closes the files."
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ldx #<_exit
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lda #>_exit
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jsr reset ; Setup RESET vector
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; Call the module constructors.
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jsr initlib
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; Switch in LC bank 2 for W/O.
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bit $C081
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bit $C081
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; Set the source start address.
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; Aka __LC_LOAD__ iff segment LC exists.
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lda #<(__ONCE_LOAD__ + __ONCE_SIZE__)
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ldy #>(__ONCE_LOAD__ + __ONCE_SIZE__)
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sta $9B
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sty $9C
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; Set the source last address.
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; Aka __LC_LOAD__ + __LC_SIZE__ iff segment LC exists.
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lda #<((__ONCE_LOAD__ + __ONCE_SIZE__) + (__LC_LAST__ - __LC_START__))
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ldy #>((__ONCE_LOAD__ + __ONCE_SIZE__) + (__LC_LAST__ - __LC_START__))
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sta $96
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sty $97
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; Set the destination last address.
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; Aka __LC_RUN__ + __LC_SIZE__ iff segment LC exists.
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lda #<__LC_LAST__
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ldy #>__LC_LAST__
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sta $94
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sty $95
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; Call into Applesoft Block Transfer Up -- which handles zero-
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; sized blocks well -- to move the content of the LC memory area.
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jsr $D39A ; BLTU2
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; Switch in LC bank 2 for R/O and return.
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bit $C080
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rts
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; ------------------------------------------------------------------------
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.code
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; Set up the RESET vector.
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reset: stx SOFTEV
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sta SOFTEV+1
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eor #$A5
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sta PWREDUP
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return: rts
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; Quit to the ProDOS dispatcher.
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quit: jsr $BF00 ; MLI call entry point
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.byte $65 ; Quit
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.word q_param
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; ------------------------------------------------------------------------
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.rodata
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; MLI parameter list for quit
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q_param:.byte $04 ; param_count
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.byte $00 ; quit_type
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.word $0000 ; reserved
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.byte $00 ; reserved
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.word $0000 ; reserved
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; ------------------------------------------------------------------------
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.data
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; Final jump when we're done
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done: jmp DOSWARM ; Potentially patched at runtime
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; ------------------------------------------------------------------------
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.segment "INIT"
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zpsave: .res zpspace
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rvsave: .res 3
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