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cc65/libsrc/geos-common/system/crt0.s
Greg King c7969a78b0 Refined the comments in the target start-up files.
Fixed typo errors.  Made the comments consistent across all those files.
2014-08-24 10:10:20 -04:00

68 lines
1.8 KiB
ArmAsm

;
; Startup code for GEOS
;
; Maciej 'YTM/Elysium' Witkowiak
; 26.10.99, 10.3.2000, 15.8.2001, 23.12.2002
.export _exit
.export __STARTUP__ : absolute = 1 ; Mark as startup
.import __STACKADDR__, __STACKSIZE__ ; Linker generated
.import __BACKBUFSIZE__ ; Linker generated
.import initlib, donelib
.import callmain
.import zerobss
.importzp sp
.include "jumptab.inc"
.include "geossym.inc"
.include "const.inc"
; ------------------------------------------------------------------------
; Place the startup code in a special segment.
.segment "STARTUP"
; GEOS 64/128 initializes the screen before starting an application while
; Apple GEOS does not. In order to provide identical startup conditions,
; we initialize the screen here, on Apple GEOS. For the same reason, we set
; the pattern and dispBufferOn, even on GEOS 64/128, although we don't use
; them here.
lda #2 ; Checkerboard pattern
jsr SetPattern
lda #<(ST_WR_FORE | .MIN (ST_WR_BACK, __BACKBUFSIZE__))
sta dispBufferOn
.ifdef __GEOS_APPLE__
jsr i_Rectangle
.byte 0
.byte SC_PIX_HEIGHT-1
.word 0
.word SC_PIX_WIDTH-1
.endif
; Clear the BSS data.
jsr zerobss
; Set up the stack.
lda #<(__STACKADDR__ + __STACKSIZE__)
ldx #>(__STACKADDR__ + __STACKSIZE__)
sta sp
stx sp+1
; Call the module constructors.
jsr initlib
; Push the command-line arguments; and, call main().
cli
jsr callmain
; Call the module destructors.
_exit: jsr donelib
jmp EnterDeskTop ; Return control to the system