elite-bcfs.asm

\************************************************
\* Prepare the Big Code File
\* ELTcode
\************************************************

C%=&F40             ; assembly address of Elite game code (elite-source.asm)
L%=&1128            ; load address of Elite game code (after LBL fn)
D%=&563A            ; hard-coded size of Elite game code (elite-source.asm)
ZP=&70

ORG &1100           ; load address of ELTcode

\ *****************************************************************************
\ Code entered at LBL+1 (&1101) as defined in elite-loader.asm CHECKV
\ Calculates checksum and compares to value in CHECKbyt (&B00) from loader
\ Any trivial modification in this code results in a machine reset (&FFFC)
\ *****************************************************************************

.LBL
 EQUB &6C            ; JMP indirect
 LDX #&60            ; &A2 &60 (RTS)
 LDA #&B
 STA ZP+1
 LDY #0
 STY ZP
 TYA
 INY
 .CHK3
 CLC
 ADC (ZP),Y
 INY
 BNE CHK3
 INC ZP+1
 .CHK4
 CLC
 ADC (ZP),Y
 INY
 BPL CHK4
 CMP &B00
 BEQ LBL+2           ; RTS
 LDA #&7F
 STA &FE4E
 JMP (&FFFC)         ; reset machine

.elitea
PRINT "elitea=",~P%
INCBIN "output/ELTA.bin"
.eliteb
PRINT "eliteb=",~P%
INCBIN "output/ELTB.bin"
.elitec
PRINT "elitec=",~P%
INCBIN "output/ELTC.bin"
.elited
PRINT "elited=",~P%
INCBIN "output/ELTD.bin"
.elitee
PRINT "elitee=",~P%
INCBIN "output/ELTE.bin"
.elitef
PRINT "elitef=",~P%
INCBIN "output/ELTF.bin"
.eliteg
PRINT "eliteg=",~P%
INCBIN "output/ELTG.bin"
.checksum0
PRINT "checksum0=",~P%
SKIP 1      ; byte skipped for checksum later
.ships
PRINT "ships=",~P%
INCBIN "data/SHIPS.bin"
.end

PRINT "P%=",~P%

\\ CHECKSUM PERFORMED IN BCFS.PY SCRIPT

PRINT "S.ELTcode 1100 ", ~(L%+&6000-C%), " ", ~L%, ~L%

\\ SAVE UNPROTECTED CODE

SAVE "output/ELTcode.unprot.bin", &1100, (L%+&6000-C%), L%

\\ SAVE JUST THE HEADER

SAVE "output/ELThead.bin", &1100, elitea, &1100