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|
;
; 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.
; 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 targets 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
.export __SYSTEM_CHECK__, __SYSCHK_END__
.import __STARTADDRESS__
; the following imports are only needed for the 'atari' target version
.import __BSS_SIZE__, __BSS_RUN__
.import __STACKSIZE__
.import __RESERVED_MEMORY__
; import our header and trailers
.forceimport __SYSCHKHDR__, __SYSCHKTRL__
.include "zeropage.inc"
.include "atari.inc"
.macro print_string text
.local start, cont
jmp cont
start: .byte text, ATEOL
cont: ldx #0 ; channel 0
lda #<start
sta ICBAL,x ; address
lda #>start
sta ICBAH,x
lda #<(cont - start)
sta ICBLL,x ; length
lda #>(cont - start)
sta ICBLH,x
lda #PUTCHR
sta ICCOM,x
jsr CIOV_org
.endmacro
.macro print_string2 addr, len
ldx #0 ; channel 0
lda #<addr
sta ICBAL,x ; address
lda #>addr
sta ICBAH,x
lda #<len
sta ICBLL,x ; length
lda #>len
sta ICBLH,x
lda #PUTCHR
sta ICCOM,x
jsr CIOV_org
.endmacro
; ------------------------------------------------------------------------
; code
.segment "SYSCHK"
rts ; for older DOSes which unconditionally run the first load chunk
.ifdef __ATARIXL__
; check for SpartaDOS and its usage of RAM below ROM
; return CF 0/1 for ok/bad
sdcheck:lda DOS
cmp #'S'
bne sdcrts0 ; not SpartaDOS, assume RAM is not used
; check for BW-DOS, which always reports itself as SpartaDOS, but doesn't use memory under the ROM
lda DOS+3 ; 'B' in BW-DOS
cmp #'B'
bne sdnobw
lda DOS+4 ; 'W' in BW-DOS
cmp #'W'
beq sdcrts0 ; BW-DOS does not use RAM below ROM
sdnobw: lda DOS+1 ; SD version
cmp #$40 ; SD-X has $40 or higher
bcc sdcrts1 ; older versions (except maybe 1.x) always use the RAM under the ROM
ldy #31 ; offset for OSRMFLG
lda (DOSVEC),y ; get OSRMFLG
bne sdcrts1
sdcrts0:clc
rts
sdcrts1:sec
rts
ramrom_txt:
.byte "Memory under ROM is in use.", ATEOL
.byte "Cannot run this program.", ATEOL
ramrom_txt_len = * - ramrom_txt
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 (atarixl) *****
syschk: lda $fcd8 ; from ostype.s
cmp #$a2
beq no_xl
; we have an XL machine, now check memory
lda RAMSIZ
cmp #$80
bcs sys_ok
jmp mem_err
sys_ok: jsr sdcheck ; check for SpartaDOS-X, and if found, whether it uses the RAM under the ROM
bcc sd_ok
print_string2 ramrom_txt, ramrom_txt_len
jmp fail
sd_ok: .include "xlmemchk.inc" ; calculate lowest address we will use when we move the screen buffer down
lda MEMLO
cmp lowadr
lda MEMLO+1
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
lda tmp
cmp #<(__BSS_RUN__ + __BSS_SIZE__)
lda tmp+1
sbc #>(__BSS_RUN__ + __BSS_SIZE__)
bcc mem_err ; program doesn't fit into memory
lda MEMLO
cmp #<__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
print_string "Stage #1 OK"
jsr delay
.endif
rts
; not enough memory
mem_err:print_string "Not enough memory."
fail: jsr delay
jmp (DOSVEC)
; short delay
.proc delay
lda #10
@loop: jsr delay1
clc
sbc #0
bne @loop
rts
delay1: ldx #0
ldy #0
@loop: dey
bne @loop
dex
bne @loop
rts
.endproc
__SYSTEM_CHECK__=syschk
__SYSCHK_END__:
.ifndef __ATARIXL__
tmp: ; outside of the load chunk, some kind of poor man's .bss
.endif
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