;
-; Atari XL startup system check
+; Atari startup system check
;
; This routine gets loaded prior to the main part of the executable
; and checks if the system is compatible to run the program.
-; It checks whether the system is an XL type one and that enough
-; memory is installed (which isn't the case for a 600XL).
-; If the system doesn't qualify, the loading of the main program
+; For the XL target it checks whether the system is an XL type one
+; and that enough memory is installed (which isn't the case for a 600XL).
+; For the non-XL target it checks whether there is enough memory
+; installed to run the program.
+; For both target it checks that the program won't load below MEMLO.
+; If one of the checks fails the loading of the main program
; is aborted by jumping to DOSVEC.
;
; Christian Groessler, chris@groessler.org, 2013
;DEBUG = 1
-.ifdef __ATARIXL__
-
.export syschk
.import __SYSCHK_LOAD__
- .import __STARTADDRESS__ ; needed by xlmemchk.inc
+ .import __STARTADDRESS__
+
+ ; the following imports are only needed for the 'atari' target version
+ .import __BSS_SIZE__, __BSS_RUN__
+ .import __STACKSIZE__
+ .import __RESERVED_MEMORY__
.include "zeropage.inc"
.include "atari.inc"
; ------------------------------------------------------------------------
-; Chunk header
+; code
-.segment "SYSCHKHDR"
-
- .word __SYSCHK_LOAD__
- .word end - 1
+.segment "SYSCHK"
-; ------------------------------------------------------------------------
-; Actual code
+.ifdef __ATARIXL__
-.segment "SYSCHK"
+lmemerrxl_txt:
+ .byte "Not enough memory to move screen", ATEOL
+ .byte "memory to low memory. Consider using", ATEOL
+ .byte "a higher load address.", ATEOL
+lmemerrxl_txt_len = * - lmemerrxl_txt
; no XL machine
no_xl: print_string "This program needs an XL machine."
jmp fail
-; entry point
-syschk:
- lda $fcd8 ; from ostype.s
+
+; ***** entry point (atarixl) *****
+
+syschk: lda $fcd8 ; from ostype.s
cmp #$a2
beq no_xl
cmp #$80
bcs sys_ok
-; not enough memory
- print_string "Not enough memory."
-fail: jsr delay
- jmp (DOSVEC)
-
+ jmp mem_err
sys_ok:
.include "xlmemchk.inc" ; calculate lowest address we will use when we move the screen buffer down
sbc lowadr+1
bcc memlo_ok
+; load address was too low
+ print_string2 lmemerrxl_txt, lmemerrxl_txt_len
+ jsr delay ; long text takes longer to read, give user additional time
+ jmp fail
+
+.else ; above 'atarixl', below 'atari'
+
+.define CIOV_org CIOV ; the print_string macros use CIOV_org, map this to CIOV
+
+lmemerr_txt:
+ .byte "Program would load below MEMLO.", ATEOL
+ .byte "Consider using a higher load address.", ATEOL
+lmemerr_txt_len = * - lmemerr_txt
+
+
+; ***** entry point (atari) *****
+
+syschk:
+ sec
+ lda MEMTOP
+ sbc #<__RESERVED_MEMORY__
+ sta tmp
+ lda MEMTOP+1
+ sbc #>__RESERVED_MEMORY__
+ sta tmp+1
+ lda tmp
+ sec
+ sbc #<__STACKSIZE__
+ sta tmp
+ lda tmp+1
+ sbc #>__STACKSIZE__
+ sta tmp+1
+
+;tmp contains address which must be above .bss's end
+
+ sec
+ lda tmp
+ sbc #<(__BSS_RUN__ + __BSS_SIZE__)
+ lda tmp+1
+ sbc #>(__BSS_RUN__ + __BSS_SIZE__)
+
+ bcc mem_err ; program doesn't fit into memory
+
+ sec
+ lda MEMLO
+ sbc #<__STARTADDRESS__
+ lda MEMLO+1
+ sbc #>__STARTADDRESS__
+ bcc memlo_ok
+
; load address was too low
print_string2 lmemerr_txt, lmemerr_txt_len
jsr delay ; long text takes longer to read, give user additional time
jmp fail
+.endif
+
; all is well(tm), launch the application
memlo_ok:
.ifdef DEBUG
.endif
rts
-
-lmemerr_txt:
- .byte "Not enough memory to move screen", ATEOL
- .byte "memory to low memory. Consider using", ATEOL
- .byte "a higher load address.", ATEOL
-lmemerr_txt_len = * - lmemerr_txt
-
+; not enough memory
+mem_err:print_string "Not enough memory."
+fail: jsr delay
+ jmp (DOSVEC)
; short delay
.proc delay
lda #10
-l: jsr delay1
+@loop: jsr delay1
clc
sbc #0
- bne l
+ bne @loop
rts
delay1: ldx #0
ldy #0
-loop: dey
- bne loop
+@loop: dey
+ bne @loop
dex
- bne loop
+ bne @loop
rts
.endproc
end:
+.ifndef __ATARIXL__
+tmp: ; outside of the load chunk, some kind of poor man's .bss
+.endif
+
+; ------------------------------------------------------------------------
+; Chunk header
+
+.segment "SYSCHKHDR"
+
+ .word __SYSCHK_LOAD__
+ .word end - 1
+
; ------------------------------------------------------------------------
; Chunk "trailer" - sets INITAD
.word INITAD
.word INITAD+1
.word syschk
-
-.endif ; .ifdef __ATARIXL__