296 lines
10 KiB
ArmAsm
Executable File
296 lines
10 KiB
ArmAsm
Executable File
********************************
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* Jewel of Kaldun loader *
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* program. *
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********************************
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TYP $FF ; system program
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ORG $2000 ; they originate @ $2000
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* General Macros --
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MOVB MAC
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LDA ]1
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STA ]2
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EOM
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MOVW MAC
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MOVB ]1;]2
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IF #=]1
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MOVB ]1/$100;]2+1
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ELSE
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MOVB ]1+1;]2+1
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FIN
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EOM
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* ProDOS Command Codes --
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OPEN = $C8 ; open file
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READ = $CA ; read file
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CLOSE = $CC ; close file
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* ProDOS addresses --
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MLI = $BF00
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* ProDOS Macro commands --
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* call: @name parameter #1;parameter #2; ... ;parameter #n
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@OPEN MAC ; @open path;file_buffer; (1K)
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MOVW ]1;D:C8PATH ; reference_number (ret)
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MOVW ]2;D:C8BUFF
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JSR _OPEN
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MOVB D:C8REF;]3
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EOM
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@READ MAC ; @read ref_num;input_buff;
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MOVB ]1;D:CAREF ; requested_length
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MOVW ]2;D:CABUFF ; (actual_length returned)
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MOVW ]3;D:CARLEN
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JSR _READ
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EOM
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@CLOSE MAC ; @close reference_number
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MOVB ]1;D:CCREF
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JSR _CLOSE
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EOM
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* Memory locations:
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PTR EQU $00 ; pointer for checksum
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LINE10 EQU $05A8 ; text line #10
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LINE12 EQU $06A8 ; " " #12
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LINE15 EQU $0450 ; " " #15
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LINE24 EQU $07D0 ; " " #24
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JOK_BUFF EQU $3000 ; ProDOS buffer
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JOK_ADDR EQU $6000 ; Address to load at
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JOK_LEN EQU $5EFF ; Length of JOK (this is max)
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JOK2BUFF EQU $3000
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JOK2ADDR EQU $0800
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JOK2LEN EQU $07FF
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TIT_BUFF EQU $3000 ; ProDOS buffer
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TIT_ADDR EQU $4000 ; Address to load at
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TIT_LEN EQU $2000 ; Length of Title (full screen)
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********************************
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* Main program: *
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********************************
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LDA #149 ; disable 80 columns
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JSR $FDED
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JSR $FB2F ; text
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JSR $FC58 ; home
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* Draw title lines:
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LDY #13
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:LINE10 LDA DATA10-1,Y
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STA LINE10+12,Y
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DEY
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BNE :LINE10
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LDY #26
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:LINE12 LDA DATA12-1,Y
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STA LINE12+6,Y
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DEY
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BNE :LINE12
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LDY #19
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:LINE15 LDA DATA15A-1,Y
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STA LINE15+9,Y
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DEY
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BNE :LINE15
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* Clear memory:
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LDY #24 ; clear the bitmap of the
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LDA #0 ; system...
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:CLRMEM STA $BF58-1,Y
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DEY
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BPL :CLRMEM
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LDA #$CF ; and set back to memory
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STA $BF58 ; as being empty except
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LDA #$01 ; ProDOS.
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STA $BF6F
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* Load in Title:
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@OPEN #TIT_NAME;#TIT_BUFF;REFNUM
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BCC :OK_TITLE
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JMP LOADERRT
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:OK_TITLE @READ REFNUM;#TIT_ADDR;#TIT_LEN
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@CLOSE REFNUM
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* Print version of Loader:
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LDY #19
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:LINE15B LDA DATA15B-1,Y
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STA LINE15+9,Y
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DEY
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BNE :LINE15B
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* Calculate checksum:
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JSR CHECKSUM
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* Load in JOK:
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@OPEN #JOK_NAME;#JOK_BUFF;REFNUM
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BCC :OK_JOK
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JMP LOADERRJ
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:OK_JOK @READ REFNUM;#JOK_ADDR;#JOK_LEN
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@CLOSE REFNUM
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* Load in JOK end game:
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@OPEN #JOK2NAME;#JOK2BUFF;REFNUM
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BCS LOADERRE
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@READ REFNUM;#JOK2ADDR;#JOK2LEN
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@CLOSE REFNUM
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* Check Checksum: (A0E647)
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LDA SUM+2
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CMP #$A0
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BNE :DATACORR
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LDA SUM+1
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CMP #$E6
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BNE DATACORR
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LDA SUM
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CMP #$47
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:DATACORR BNE DATACORR
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* Start JOK:
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JMP JOK_ADDR ; begin game!
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LOADERRT LDA #>TIT_NAME
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LDY #<TIT_NAME
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JMP :MSG
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LOADERRJ LDA #>JOK_NAME
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LDY #<JOK_NAME
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JMP :MSG
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LOADERRE LDA #>JOK2NAME
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LDY #<JOK2NAME
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:MSG PHA
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TYA
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PHA
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LDY #40
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:LOOP1 LDA ERRORMSG-1,Y
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STA LINE24-1,Y
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DEY
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BNE :LOOP1
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* Print filename on LINE24 overlaying <FILENAME> in the text...
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PLA
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STA PTR
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PLA
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STA PTR+1
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LDY #0
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LDA (PTR),Y ; length byte
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TAX
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:LOOP2 INY
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LDA (PTR),Y
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STA LINE24+7,Y
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DEX
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BNE :LOOP2
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ERRORXX JSR $FF3A ; bell
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FOREVER LDA #<$0200 ; sets $03F0 (BRK address) to
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STA $3F0 ; point at $0200.
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STA $201 ; And, sets $0200:4C 00 02
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LDA #>$0200 ; ie, JMP $0200.
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STA $3F1 ; ... the begining of FOREVER!
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STA $202
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LDA #$4C
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STA $200
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LDA $3F3 ; scramble power-up byte, so
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EOR #%11111111 ; power-up automatically occurs
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STA $3F3 ; upon RESET.
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LDY #0 ; prepare to erase memory from
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LDA #<$4000 ; $4000 - $BEFF ...
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STA $00
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LDA #>$4000
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STA $01
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LDA #0
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:ERASE STA ($00),Y ; erase a page.
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INY
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BNE :ERASE
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INC $01 ; add 1 to hi byte
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LDA $01
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CMP #$BF ; at end?
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BLT :ERASE ; nope, do more
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LDA #$20 ; yes: Erase loader program.
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STA $01 ; will exit when BRK
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JMP :ERASE ; encountered.
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DATACORR LDY #28
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:LOOP LDA DATA15C-1,Y
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STA LINE15+5,Y
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DEY
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BNE :LOOP
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JSR $FF3A ; bell
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JMP FOREVER
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ERRORMSG ASC "ERROR: <FILENAME> IS UNACCESSABLE!"
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JOK2NAME STR "JEWEL.END.GAME"
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JOK_NAME STR "JEWEL.OF.KALDUN"
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TIT_NAME STR "JEWEL.TITLE.PIC"
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REFNUM HEX 00
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DATA10 INV " PLEASE WAIT "
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DATA12 ASC "JEWEL OF KALDUN IS LOADING"
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DATA15A ASC " L O A D E R "
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DATA15B ASC "LOADER: VERSION 1.3"
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DATA15C ASC "CANNOT LOAD: DATA CORRUPTED!"
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* ProDOS Routines --
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_OPEN JSR MLI ; perform open function
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DFB OPEN
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DW D:OPEN
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RTS
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_READ JSR MLI ; perform read function
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DFB READ
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DW D:READ
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RTS
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_CLOSE JSR MLI ; perform close function
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DFB CLOSE
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DW D:CLOSE
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RTS
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* ProDOS data/parameters --
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D:OPEN DFB $3 ; 3 parameters
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D:C8PATH DW 0 ; address of path name
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D:C8BUFF DW 0 ; address of file buffer
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D:C8REF DFB 0 ; reference number (returned)
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D:READ DFB $4 ; 4 parameters
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D:CAREF DFB 0 ; reference number
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D:CABUFF DW 0 ; address of data buffer
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D:CARLEN DW 0 ; requested length
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D:CAALEN DW 0 ; actual length
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D:CLOSE DFB $1 ; 1 parameter
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D:CCREF DFB 0 ; reference number
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********************************
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* Compute a checksum on the *
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* graphic title page after *
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* being loaded into memory. *
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********************************
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CHECKSUM LDA #$00 ; point to location
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STA PTR ; $4000, beginning
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LDA #$40 ; of graphics page
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STA PTR+1
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LDA #0 ; initialize checksum
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STA SUM ; to be zero.
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STA SUM+1
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STA SUM+2
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LDY #0
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:LOOP CLC
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LDA (PTR),Y ; grab byte
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ADC SUM ; and add it to
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STA SUM ; the sum.
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ADC SUM+1 ; add following
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STA SUM+1 ; carry bits.
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ADC SUM+2
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STA SUM+2
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INY
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BNE :LOOP
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INC PTR+1
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CMP #$60 ; check if done
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BLT :LOOP ; if not, continue
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LDA SUM+2 ; dump sum to screen.
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JSR $FDDA ; will be replaced to
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LDA SUM+1 ; actually check if a
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JSR $FDDA ; an unmodified page
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LDA SUM ; was loaded.
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JSR $FDDA
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RTS
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SUM HEX 000000 ; check sum
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* Save file:
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SAV JOK.SYSTEM.bin
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