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cc65/libsrc/apple2/crt0.s
ol.sc 5c35c213f6 Added author hint - as contained in the other source files.
git-svn-id: svn://svn.cc65.org/cc65/trunk@4211 b7a2c559-68d2-44c3-8de9-860c34a00d81
2009-09-22 17:30:50 +00:00

314 lines
8.6 KiB
ArmAsm

;
; Oliver Schmidt, 15.09.2009
;
; Startup code for cc65 (Apple2 version)
;
.export _exit, done, return
.export __STARTUP__ : absolute = 1 ; Mark as startup
.import zerobss
.import initlib, donelib
.import callmain, callirq
.import __RAM_START__ , __RAM_LAST__ ; Linker generated
.import __MOVE_START__, __MOVE_LAST__ ; Linker generated
.import __LC_START__ , __LC_LAST__ ; Linker generated
.import __ZPSAVE_RUN__, __INIT_SIZE__ ; Linker generated
.import __INTERRUPTOR_COUNT__ ; Linker generated
.include "zeropage.inc"
.include "apple2.inc"
.linecont +
; ------------------------------------------------------------------------
.segment "EXEHDR"
.addr __RAM_START__ ; Start address
.word __ZPSAVE_RUN__ - __RAM_START__ + \
__MOVE_LAST__ - __MOVE_START__ ; Size
; ------------------------------------------------------------------------
.segment "STARTUP"
; 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
; Switch in LC bank 2 for W/O
bit $C081
bit $C081
; Set source start address
lda #<(__ZPSAVE_RUN__ + __INIT_SIZE__)
ldy #>(__ZPSAVE_RUN__ + __INIT_SIZE__)
sta $9B
sty $9C
; Set source last address
lda #<(__ZPSAVE_RUN__ + __INIT_SIZE__ + __LC_LAST__ - __LC_START__)
ldy #>(__ZPSAVE_RUN__ + __INIT_SIZE__ + __LC_LAST__ - __LC_START__)
sta $96
sty $97
; Set destination last address
lda #<__LC_LAST__
ldy #>__LC_LAST__
sta $94
sty $95
; Call into Applesoft Block Transfer Utility - which handles zero
; sized blocks well - to move content of the LC memory area
jsr $D396 ; BLTU + 3
; Set source start address
lda #<__ZPSAVE_RUN__
ldy #>__ZPSAVE_RUN__
sta $9B
sty $9C
; Set source last address
lda #<(__ZPSAVE_RUN__ + __INIT_SIZE__)
ldy #>(__ZPSAVE_RUN__ + __INIT_SIZE__)
sta $96
sty $97
; Set destination last address
lda #<__RAM_LAST__
ldy #>__RAM_LAST__
sta $94
sty $95
; Call into Applesoft Block Transfer Utility - which handles moving
; overlapping blocks upwards well - to move the INIT segment
jsr $D396 ; BLTU + 3
; Delegate all further processing to keep the STARTUP segment small
jsr init
; Avoid re-entrance of donelib. This is also the _exit entry
_exit: ldx #<exit
lda #>exit
jsr reset ; Setup RESET vector
; Switch in ROM in case it wasn't already switched in by a RESET
bit $C082
; Call module destructors
jsr donelib
; Check for valid interrupt vector table entry number
lda int_num
beq exit
; Deallocate interrupt vector table entry
dec i_param ; Adjust parameter count
jsr $BF00 ; MLI call entry point
.byte $41 ; Dealloc interrupt
.addr i_param
; Restore the original RESET vector
exit: ldx #$02
: lda rvsave,x
sta SOFTEV,x
dex
bpl :-
; Copy back the zero page stuff
ldx #zpspace-1
: lda zpsave,x
sta sp,x
dex
bpl :-
; 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
; We're done
jmp (done)
; ------------------------------------------------------------------------
.segment "INIT"
; Save the zero page locations we need
init: ldx #zpspace-1
: lda sp,x
sta zpsave,x
dex
bpl :-
; Clear the BSS data
jsr zerobss
; Save the original RESET vector
ldx #$02
: lda SOFTEV,x
sta rvsave,x
dex
bpl :-
; 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
; Check for ProDOS
ldy $BF00 ; MLI call entry point
cpy #$4C ; Is MLI present? (JMP opcode)
bne basic
; Check ProDOS system bit map
lda $BF6F ; protection for pages $B8 - $BF
cmp #%00000001 ; exactly system global page is protected
bne basic
; No BASIC.SYSTEM so quit to ProDOS dispatcher instead
lda #<quit
ldx #>quit
sta done
stx done+1
; No BASIC.SYSTEM so use addr of ProDOS system global page
lda #<$BF00
ldx #>$BF00
bne :+ ; Branch always
; Get highest available mem addr from BASIC interpreter
basic: lda HIMEM
ldx HIMEM+1
; Setup the C stack
: sta sp
stx sp+1
; Check for interruptors
lda #<__INTERRUPTOR_COUNT__
beq :+
; Check for ProDOS
cpy #$4C ; Is MLI present? (JMP opcode)
bne prterr
; Allocate interrupt vector table entry
jsr $BF00 ; MLI call entry point
.byte $40 ; Alloc interrupt
.addr i_param
bcs prterr
; Enable interrupts as old ProDOS versions (i.e. 1.1.1)
; jump to SYS and BIN programs with interrupts disabled
cli
; Call module constructors
: jsr initlib
; Switch in LC bank 2 for R/O
bit $C080
; Push arguments and call main()
jmp callmain
; Print error message and return
prterr: ldx #msglen-1
: lda errmsg,x
jsr $FDED ; COUT
dex
bpl :-
rts
errmsg: .ifdef __APPLE2ENH__
.byte $8D, 't'|$80, 'p'|$80, 'u'|$80, 'r'|$80, 'r'|$80
.byte 'e'|$80, 't'|$80, 'n'|$80, 'i'|$80, ' '|$80, 'c'|$80
.byte 'o'|$80, 'l'|$80, 'l'|$80, 'a'|$80, ' '|$80, 'o'|$80
.byte 't'|$80, ' '|$80, 'd'|$80, 'e'|$80, 'l'|$80, 'i'|$80
.byte 'a'|$80, 'F'|$80, $8D
.else
.byte $8D, 'T'|$80, 'P'|$80, 'U'|$80, 'R'|$80, 'R'|$80
.byte 'E'|$80, 'T'|$80, 'N'|$80, 'I'|$80, ' '|$80, 'C'|$80
.byte 'O'|$80, 'L'|$80, 'L'|$80, 'A'|$80, ' '|$80, 'O'|$80
.byte 'T'|$80, ' '|$80, 'D'|$80, 'E'|$80, 'L'|$80, 'I'|$80
.byte 'A'|$80, 'F'|$80, $8D
.endif
msglen = * - errmsg
; ------------------------------------------------------------------------
.segment "LOWCODE"
; ProDOS TechRefMan, chapter 6.2:
; "Each installed routine must begin with a CLD instruction."
intptr: cld
; Call interruptors and check for success
jsr callirq
bcc :+
; ProDOS TechRefMan, chapter 6.2:
; "When the routine that can process the interrupt is called, it
; should ... return (via an RTS) with the carry flag clear."
clc
rts
; ProDOS TechRefMan, chapter 6.2:
; "When a routine that cannot process the interrupt is called,
; it should return (via an RTS) with the cary flag set ..."
: sec
rts
; Setup RESET vector
reset: stx SOFTEV
sta SOFTEV+1
eor #$A5
sta PWREDUP
return: rts
; Quit to ProDOS dispatcher
quit: jsr $BF00 ; MLI call entry point
.byte $65 ; Quit
.word q_param
; ------------------------------------------------------------------------
.rodata
; MLI parameter list for quit
q_param:.byte $04 ; param_count
.byte $00 ; quit_type
.word $0000 ; reserved
.byte $00 ; reserved
.word $0000 ; reserved
; ------------------------------------------------------------------------
.data
; MLI parameter list for (de)alloc interrupt
i_param:.byte $02 ; param_count
int_num:.byte $00 ; int_num
.addr intptr ; int_code
; Location to jump to when we're done
done: .addr DOSWARM
; ------------------------------------------------------------------------
.segment "ZPSAVE"
zpsave: .res zpspace
; ------------------------------------------------------------------------
.bss
rvsave: .res 3