;
-; Startup code for cc65 (Apple2 version)
+; Oliver Schmidt, 2009-09-15
;
-; This must be the *first* file on the linker command line
+; Startup code for cc65 (Apple2 version)
;
- .export _exit
- .import initlib, donelib
- .import zerobss, push0
- .import __STARTUP_LOAD__, __BSS_LOAD__ ; Linker generated
- .import _main
+ .export _exit, done, return
+ .export __STARTUP__ : absolute = 1 ; Mark as startup
- .include "zeropage.inc"
- .include "apple2.inc"
-
-; ------------------------------------------------------------------------
-; The executable header
-
-.segment "EXEHDR"
-
- .word __STARTUP_LOAD__ ; Start address
- .word __BSS_LOAD__ - __STARTUP_LOAD__ ; Size
-
-; ------------------------------------------------------------------------
-; Create an empty LOWCODE segment to avoid linker warnings
+ .import initlib, donelib
+ .import zerobss, callmain
+ .import __ONCE_LOAD__, __ONCE_SIZE__ ; Linker generated
+ .import __LC_START__, __LC_LAST__ ; Linker generated
-.segment "LOWCODE"
+ .include "zeropage.inc"
+ .include "apple2.inc"
; ------------------------------------------------------------------------
-; Place the startup code in a special segment.
-
-.segment "STARTUP"
- ldx #zpspace-1
-L1: lda sp,x
- sta zpsave,x ; Save the zero page locations we need
- dex
- bpl L1
+ .segment "STARTUP"
-; Clear the BSS data
+ ; ProDOS TechRefMan, chapter 5.2.1:
+ ; "For maximum interrupt efficiency, a system program should not
+ ; use more than the upper 3/4 of the stack."
+ ldx #$FF
+ txs ; Init stack pointer
- jsr zerobss
+ ; Save space by putting some of the start-up code in the ONCE segment,
+ ; which can be re-used by the BSS segment, the heap and the C stack.
+ jsr init
-; Save system stuff and setup the stack
+ ; Clear the BSS data.
+ jsr zerobss
- tsx
- stx spsave ; Save the system stack ptr
+ ; Push the command-line arguments; and, call main().
+ jsr callmain
- lda MEMSIZE
- sta sp
- lda MEMSIZE+1
- sta sp+1 ; Set argument stack ptr
+ ; Avoid a re-entrance of donelib. This is also the exit() entry.
+_exit: ldx #<exit
+ lda #>exit
+ jsr reset ; Setup RESET vector
-; Call module constructors
+ ; Switch in ROM, in case it wasn't already switched in by a RESET.
+ bit $C082
- jsr initlib
+ ; Call the module destructors.
+ jsr donelib
-; Initialize conio stuff
+ ; Restore the original RESET vector.
+exit: ldx #$02
+: lda rvsave,x
+ sta SOFTEV,x
+ dex
+ bpl :-
- lda #$ff
- sta TEXTTYP
+ ; Copy back the zero-page stuff.
+ ldx #zpspace-1
+: lda zpsave,x
+ sta sp,x
+ dex
+ bpl :-
-; Set up to use Apple ROM $C000-$CFFF
+ ; ProDOS TechRefMan, chapter 5.2.1:
+ ; "System programs should set the stack pointer to $FF at the
+ ; warm-start entry point."
+ ldx #$FF
+ txs ; Re-init stack pointer
- ;; sta USEROM
+ ; We're done
+ jmp done
-; Pass an empty command line
+; ------------------------------------------------------------------------
- jsr push0 ; argc
- jsr push0 ; argv
+ .segment "ONCE"
+
+ ; Save the zero-page locations that we need.
+init: ldx #zpspace-1
+: lda sp,x
+ sta zpsave,x
+ dex
+ bpl :-
+
+ ; Save the original RESET vector.
+ ldx #$02
+: lda SOFTEV,x
+ sta rvsave,x
+ dex
+ bpl :-
+
+ ; Check for ProDOS.
+ ldy $BF00 ; MLI call entry point
+ cpy #$4C ; Is MLI present? (JMP opcode)
+ bne basic
+
+ ; Check the ProDOS system bit map.
+ lda $BF6F ; Protection for pages $B8 - $BF
+ cmp #%00000001 ; Exactly system global page is protected
+ bne basic
+
+ ; No BASIC.SYSTEM; so, quit to the ProDOS dispatcher instead.
+ lda #<quit
+ ldx #>quit
+ sta done+1
+ stx done+2
+
+ ; No BASIC.SYSTEM; so, use the addr of the ProDOS system global page.
+ lda #<$BF00
+ ldx #>$BF00
+ bne :+ ; Branch always
+
+ ; Get the highest available mem addr from the BASIC interpreter.
+basic: lda HIMEM
+ ldx HIMEM+1
+
+ ; Set up the C stack.
+: sta sp
+ stx sp+1
+
+ ; ProDOS TechRefMan, chapter 5.3.5:
+ ; "Your system program should place in the RESET vector the
+ ; address of a routine that ... closes the files."
+ ldx #<_exit
+ lda #>_exit
+ jsr reset ; Setup RESET vector
+
+ ; Call the module constructors.
+ jsr initlib
+
+ ; Switch in LC bank 2 for W/O.
+ bit $C081
+ bit $C081
+
+ ; Set the source start address.
+ ; Aka __LC_LOAD__ iff segment LC exists.
+ lda #<(__ONCE_LOAD__ + __ONCE_SIZE__)
+ ldy #>(__ONCE_LOAD__ + __ONCE_SIZE__)
+ sta $9B
+ sty $9C
+
+ ; Set the source last address.
+ ; Aka __LC_LOAD__ + __LC_SIZE__ iff segment LC exists.
+ lda #<((__ONCE_LOAD__ + __ONCE_SIZE__) + (__LC_LAST__ - __LC_START__))
+ ldy #>((__ONCE_LOAD__ + __ONCE_SIZE__) + (__LC_LAST__ - __LC_START__))
+ sta $96
+ sty $97
+
+ ; Set the destination last address.
+ ; Aka __LC_RUN__ + __LC_SIZE__ iff segment LC exists.
+ lda #<__LC_LAST__
+ ldy #>__LC_LAST__
+ sta $94
+ sty $95
+
+ ; Call into Applesoft Block Transfer Up -- which handles zero-
+ ; sized blocks well -- to move the content of the LC memory area.
+ jsr $D39A ; BLTU2
+
+ ; Switch in LC bank 2 for R/O and return.
+ bit $C080
+ rts
- ldy #4 ; Argument size
- jsr _main ; call the users code
+; ------------------------------------------------------------------------
-; Call module destructors. This is also the _exit entry.
+ .code
-_exit: jsr donelib
+ ; Set up the RESET vector.
+reset: stx SOFTEV
+ sta SOFTEV+1
+ eor #$A5
+ sta PWREDUP
+return: rts
-; Restore system stuff
+ ; Quit to the ProDOS dispatcher.
+quit: jsr $BF00 ; MLI call entry point
+ .byte $65 ; Quit
+ .word q_param
- lda #$ff ; Reset text mode
- sta TEXTTYP
+; ------------------------------------------------------------------------
- ldx spsave
- txs ; Restore stack pointer
+ .rodata
-; Copy back the zero page stuff
+ ; MLI parameter list for quit
+q_param:.byte $04 ; param_count
+ .byte $00 ; quit_type
+ .word $0000 ; reserved
+ .byte $00 ; reserved
+ .word $0000 ; reserved
- ldx #zpspace-1
-L2: lda zpsave,x
- sta sp,x
- dex
- bpl L2
+; ------------------------------------------------------------------------
-; Reset changed vectors, back to basic
+ .data
- jmp RESTOR
+ ; Final jump when we're done
+done: jmp DOSWARM ; Potentially patched at runtime
; ------------------------------------------------------------------------
-; Data
-
-.data
-
-zpsave: .res zpspace
-.bss
+ .segment "INIT"
-spsave: .res 1
+zpsave: .res zpspace
+rvsave: .res 3
projects / cc65 / blobdiff