020fe4028a
On a 48k Apple II, the BLTU2 call throws an error, even when there is nothing to copy in the LC segment. Add an alternative LC copy, based on memcpy, to an extra file that the user can link in as with iobuf-0800. This memcpy-based version allows our programs to run on Integer ROM apple2. It costs 21 bytes in binary size, plus memcpy (60 bytes in binary size + RAM use) if it wasn't already linked in.
171 lines
5.0 KiB
ArmAsm
171 lines
5.0 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 bltu2
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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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; Copy the LC segment to its destination
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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 bltu2 ; 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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