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|
;
; Startup code for cc65 (ATARI version)
;
; Contributing authors:
; Mark Keates
; Freddy Offenga
; Christian Groessler
; Stefan Haubenthal
;
.export __STARTUP__ : absolute = 1 ; Mark as startup
.export _exit, start, excexit, SP_save
.import initlib, donelib
.import callmain, zerobss
.import __RESERVED_MEMORY__
.import __MAIN_START__, __MAIN_SIZE__
.import __LOWCODE_RUN__, __LOWCODE_SIZE__
.ifdef __ATARIXL__
.import __STACKSIZE__
.import sram_init
.import scrdev
.import findfreeiocb
.forceimport sramprep ; force inclusion of the "shadow RAM preparation" load chunk
.include "save_area.inc"
.endif
.include "zeropage.inc"
.include "atari.inc"
; ------------------------------------------------------------------------
.segment "STARTUP"
rts ; fix for SpartaDOS / OS/A+
; They first call the entry point from AUTOSTRT; and
; then, the load address (this rts here).
; We point AUTOSTRT directly after the rts.
; Real entry point:
start:
.ifdef __ATARIXL__
jsr sram_init
.endif
; Clear the BSS data.
jsr zerobss
; Set up the stack.
tsx
stx SP_save
.ifdef __ATARIXL__
lda #<(__MAIN_START__ + __MAIN_SIZE__ + __STACKSIZE__)
ldx #>(__MAIN_START__ + __MAIN_SIZE__ + __STACKSIZE__)
sta sp
stx sp+1
.else
; Report the memory usage.
lda APPMHI
ldx APPMHI+1
sta APPMHI_save ; remember old APPMHI value
stx APPMHI_save+1
sec
lda MEMTOP
sbc #<__RESERVED_MEMORY__
sta APPMHI ; initialize our APPMHI value
sta sp ; set up runtime stack part 1
lda MEMTOP+1
sbc #>__RESERVED_MEMORY__
sta APPMHI+1
sta sp+1 ; set up runtime stack part 2
.endif
; Call the module constructors.
jsr initlib
; Set the left margin to 0.
lda LMARGN
sta LMARGN_save
ldy #0
sty LMARGN
; Set the keyboard to upper-/lower-case mode.
ldx SHFLOK
stx SHFLOK_save
sty SHFLOK
; Initialize the conio stuff.
dey ; Set Y to $FF
sty CH ; remove keypress which might be in the input buffer
; Push the command-line arguments; and, call main().
jsr callmain
; Call the module destructors. This is also the exit() entry.
_exit: ldx SP_save
txs ; Restore stack pointer
; Restore the system stuff.
excexit:jsr donelib ; Run module destructors; 'excexit' is called from the exec routine
; Restore the left margin.
lda LMARGN_save
sta LMARGN
; Restore the kb mode.
lda SHFLOK_save
sta SHFLOK
; Restore APPMHI.
lda APPMHI_save
ldx APPMHI_save+1
sta APPMHI
stx APPMHI+1
.ifdef __ATARIXL__
; Atari XL target stuff...
lda PORTB_save
sta PORTB
lda RAMTOP_save
sta RAMTOP
lda MEMTOP_save
ldx MEMTOP_save+1
sta MEMTOP
stx MEMTOP+1
; Issue a GRAPHICS 0 call (copied'n'pasted from the TGI drivers), in
; order to restore screen memory to its default location just
; before the ROM.
jsr findfreeiocb
; Reopen it in Graphics 0
lda #OPEN
sta ICCOM,x
lda #OPNIN | OPNOT
sta ICAX1,x
lda #0
sta ICAX2,x
lda #<scrdev
sta ICBAL,x
lda #>scrdev
sta ICBAH,x
lda #3
sta ICBLL,x
lda #0
sta ICBLH,x
jsr CIOV_org
; No error checking here, shouldn't happen(TM); and, no way to
; recover anyway.
lda #CLOSE
sta ICCOM,x
jsr CIOV_org
.endif
; Turn on the cursor.
ldx #0
stx CRSINH
; Back to DOS.
rts
; *** end of main startup code
; ------------------------------------------------------------------------
.bss
SP_save: .res 1
SHFLOK_save: .res 1
LMARGN_save: .res 1
.ifndef __ATARIXL__
APPMHI_save: .res 2
.endif
; ------------------------------------------------------------------------
.segment "LOWCODE" ; have at least one (empty) segment of LOWCODE, so that the next line works even if the program doesn't make use of this segment
.assert (__LOWCODE_RUN__ + __LOWCODE_SIZE__ <= $4000 || __LOWCODE_RUN__ > $7FFF || __LOWCODE_SIZE__ = 0), warning, "'lowcode area' reaches into $4000..$7FFF bank memory window"
; check for LOWBSS_SIZE = 0 not needed since the only file which uses LOWBSS (irq.s) also uses LOWCODE
; check for LOWCODE_RUN > $7FFF is mostly for cartridges, where this segment is loaded high (into cart ROM)
; there is a small chance that if the user loads the program really high, LOWCODE is above $7FFF, but LOWBSS is below -- no warning emitted in this case
|
