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Improved and much smaller bootloader by Karri Kaksonen.
git-svn-id: svn://svn.cc65.org/cc65/trunk@4978 b7a2c559-68d2-44c3-8de9-860c34a00d81
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@ -3,6 +3,8 @@
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;
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; This header is required for cart builds.
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;
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.include "lynx.inc"
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.include "extzp.inc"
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.import __RAM_START__
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.import __CODE_SIZE__,__DATA_SIZE__,__RODATA_SIZE__
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.import __STARTUP_SIZE__,__INIT_SIZE__
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@ -23,99 +25,198 @@
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; rotation 2=right
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.byte 0,0,0,0,0 ; spare
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.if (.match (__BLOCKSIZE__, 2048))
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__LOADER_SIZE__=0
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.elseif (.match (__BLOCKSIZE__, 512))
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__LOADER_SIZE__=0
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.else
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__LOADER_SIZE__=410
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;**********************************
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; Here is the bootloader in plaintext
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; The idea is to make the smalles possible encrypted loader as decryption
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; is very slow. The minimum size is 49 bytes plus a zero byte.
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;**********************************
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; EXE = $f000
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;
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; .org $0200
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;
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; ; 1. force Mikey to be in memory
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; stz MAPCTL
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;
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; ; 3. set ComLynx to open collector
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; lda #4 ; a = 00000100
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; sta SERCTL ; set the ComLynx to open collector
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;
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; ; 4. make sure the ROM is powered on
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; lda #8 ; a = 00001000
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; sta IODAT ; set the ROM power to on
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;
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; ; 5. read in secondary exe + 8 bytes from the cart and store it in $f000
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; ldx #0 ; x = 0
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; ldy #$AB ; y = secondary loader
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;rloop1: lda RCART0 ; read a byte from the cart
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; sta EXE,X ; EXE[X] = a
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; inx ; x++
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; dey ; y--
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; bne rloop1 ; loops until y wraps
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;
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; ; 6. jump to secondary loader
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; jmp EXE ; run the secondary loader
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;
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; .reloc
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;**********************************
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; After compilation, encryption and obfuscation it turns into this.
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;**********************************
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__LOADER_SIZE__=52
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.byte $ff, $dc, $e3, $bd, $bc, $7f, $f8, $94
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.byte $b7, $dd, $68, $bb, $da, $5b, $50, $5c
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.byte $ea, $9f, $2b, $df, $96, $80, $3f, $7e
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.byte $ef, $15, $81, $ae, $ad, $e4, $6e, $b3
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.byte $46, $d7, $72, $58, $f7, $76, $8a, $4a
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.byte $c7, $99, $bd, $ff, $02, $3e, $5b, $3f
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.byte $0c, $49, $1b, $22
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; The cart starts with an encrypted loader for 1024 bytes/block
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; images. The size of the loader is 410 bytes followed by two
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; mandatory directory entries.
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.byte $FD,$C1,$0D,$8E,$E9,$EE,$09,$13,$E5,$96
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.byte $0C,$34,$64,$DA,$D4,$BB,$99,$EC,$CE,$4F
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.byte $AA,$8C,$ED,$65,$F0,$32,$70,$A3,$84,$C4
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.byte $FC,$A2,$6D,$3A,$F8,$77,$4B,$AC,$9B,$54
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.byte $7D,$82,$6F,$F8,$A5,$06,$4D,$7B,$77,$55
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.byte $E4,$31,$C4,$2C,$2F,$2F,$B6,$4D,$15,$A9
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.byte $C7,$99,$5D,$6E,$B3,$97,$92,$44,$7B,$2B
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.byte $85,$18,$E6,$F1,$96,$F4,$C4,$DE,$A4,$CF
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.byte $79,$E2,$C1,$1A,$E0,$0C,$93,$C5,$26,$BD
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.byte $A3,$16,$8A,$C3,$59,$A0,$39,$38,$A0,$3B
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.byte $EF,$BB,$1D,$5C,$0D,$1D,$CC,$48,$1D,$DD
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.byte $98,$9A,$7A,$F7,$96,$F9,$61,$03,$50,$DA
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.byte $47,$69,$94,$C3,$80,$DA,$A9,$99,$A1,$21
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.byte $2B,$2E,$7D,$F5,$E4,$F7,$B3,$5C,$A8,$14
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.byte $FA,$E9,$06,$AC,$1E,$9F,$B5,$31,$BE,$42
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.byte $14,$08,$0E,$05,$FB,$25,$BB,$5C,$5C,$66
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.byte $76,$8E,$36,$E8,$EB,$39,$F2,$26,$BD,$17
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.byte $29,$F4,$B8,$1D,$7E,$EE,$47,$61,$BB,$9E
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.byte $F5,$72,$C9,$BC,$26,$37,$D5,$78,$8F,$D0
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.byte $CE,$95,$21,$EB,$4A,$07,$8D,$3A,$3A,$01
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.byte $82,$CF,$01,$C5,$1E,$1D,$A8,$41,$4F,$BD
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.byte $C1,$76,$22,$A3,$88,$D9,$57,$C9,$51,$3A
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.byte $26,$BE,$4A,$1A,$7F,$42,$61,$CF,$FC,$FC
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.byte $5B,$06,$94,$D2,$2C,$78,$45,$BA,$93,$C4
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.byte $7D,$7C,$81,$73,$07,$4F,$E2,$6C,$E9,$81
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.byte $1A,$DE,$77,$74,$87,$DE,$26,$9E,$7A,$A8
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.byte $19,$A7,$34,$32,$70,$ED,$59,$A8,$4A,$D8
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.byte $FE,$CB,$DD,$02,$2F,$CE,$92,$E9,$13,$A6
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.byte $FF,$B4,$4B,$18,$9D,$63,$48,$E0,$3B,$3B
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.byte $0D,$2B,$FC,$04,$A4,$E3,$5E,$4C,$3C,$94
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.byte $70,$C4,$F0,$64,$15,$48,$68,$17,$DE,$14
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.byte $72,$F0,$59,$33,$4C,$49,$47,$8D,$B6,$F4
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.byte $82,$4E,$B7,$4E,$01,$C9,$C2,$82,$0B,$7A
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.byte $AC,$67,$9B,$0F,$04,$E1,$B6,$78,$34,$C8
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.byte $4F,$2A,$11,$ED,$D0,$1C,$6D,$CD,$3D,$47
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.byte $09,$8B,$E5,$38,$19,$7A,$31,$6E,$30,$71
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.byte $1C,$90,$34,$E5,$44,$CC,$00,$C7,$41,$D0
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.byte $27,$8A,$06,$29,$5C,$2B,$E4,$26,$63,$09
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.byte $52,$D3,$97,$33,$D7,$59,$1C,$36,$2F,$C9
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.byte $A9,$A2,$B5,$BB,$A9,$1D,$E6,$36,$7E,$56
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.byte $05,$A4,$9C,$E0,$45,$59,$21,$E1,$E6,$21
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.endif
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;**********************************
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; Now we have the secondary loader
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;**********************************
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__LOADER2_SIZE__=171
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.org $f000
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; 1. Read in the 1st File-entry (main exe) in FileEntry
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ldx #$00
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ldy #8
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rloop: lda RCART0 ; read a byte from the cart
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sta _FileEntry,X ; EXE[X] = a
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inx
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dey
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bne rloop
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; The directory structure required by the 410 byte bootloader
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__DIRECTORY_START__:
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; Entry 0 - title sprite (mandatory)
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off0=__LOADER_SIZE__+(__DIRECTORY_END__-__DIRECTORY_START__)
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blocka=off0/__BLOCKSIZE__
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len0=(__TITLE_END__-__TITLE_START__)
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.byte <blocka
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.word off0 & (__BLOCKSIZE__ - 1)
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.byte $00
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.word __TITLE_START__
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.word len0
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; 2. Set the block hardware to the main exe start
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lda _FileStartBlock
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sta _FileCurrBlock
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jsr seclynxblock
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; Entry 1 - first executable (mandatory)
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off1=off0+len0
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block1=off1/__BLOCKSIZE__
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len1=__STARTUP_SIZE__+__INIT_SIZE__+__CODE_SIZE__+__DATA_SIZE__+__RODATA_SIZE__
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.byte <block1
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.word off1 & (__BLOCKSIZE__ - 1)
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.byte $88
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.word __RAM_START__
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.word len1
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__DIRECTORY_END__:
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.org $2400
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__TITLE_START__:
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; The palette for the title sprite. Complete black.
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.byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
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.byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
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; The title sprite
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cls_sprite:
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.byte %00000001 ; A pixel sprite
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.byte %00010000
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.byte %00100000
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.addr 0,pixel_bitmap
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.word 0
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.word 0
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.word $a000 ; 160
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.word $6600 ; 102
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.byte $00
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pixel_bitmap:
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.byte 3,%10000100,%00000000, $0 ; A pixel bitmap
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__TITLE_END__:
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; 3. Skip over the block offset
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lda _FileBlockOffset
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ldx _FileBlockOffset+1
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phx ; The BLL kit uses negative offsets
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plx ; while the basic Lynx uses positive
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bmi @1 ; Make all offsets negative
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eor #$FF
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pha
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txa
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eor #$FF
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bra @2
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@1: pha
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txa
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@2: tay
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plx
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jsr seclynxskip0
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; 4. Read in the main exe to RAM
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lda _FileDestAddr
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ldx _FileDestAddr+1
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sta _FileDestPtr
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stx _FileDestPtr+1
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lda _FileFileLen
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ldx _FileFileLen+1
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phx ; The BLL kit uses negative counts
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plx ; while the basic Lynx uses positive
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bmi @3 ; make all counts negative
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eor #$FF
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pha
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txa
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eor #$FF
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bra @4
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@3: pha
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txa
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@4: tay
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plx
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jsr seclynxread0
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; 5. Jump to start of the main exe code
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jmp (_FileDestAddr)
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;**********************************
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; Skip bytes on bank 0
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; X:Y count (EOR $FFFF)
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;**********************************
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seclynxskip0:
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inx
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bne @0
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iny
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beq exit
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@0: jsr secreadbyte0
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bra seclynxskip0
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;**********************************
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; Read bytes from bank 0
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; X:Y count (EOR $ffff)
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;**********************************
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seclynxread0:
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inx
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bne @1
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iny
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beq exit
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@1: jsr secreadbyte0
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sta (_FileDestPtr)
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inc _FileDestPtr
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bne seclynxread0
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inc _FileDestPtr+1
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bra seclynxread0
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;**********************************
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; Read one byte from cartridge
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;**********************************
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secreadbyte0:
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lda RCART0
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inc _FileBlockByte
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bne exit
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inc _FileBlockByte+1
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bne exit
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;**********************************
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; Select a block
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;**********************************
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seclynxblock:
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pha
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phx
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phy
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lda __iodat
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and #$fc
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tay
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ora #2
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tax
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lda _FileCurrBlock
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inc _FileCurrBlock
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sec
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bra @2
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@0: bcc @1
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stx IODAT
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clc
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@1: inx
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stx SYSCTL1
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dex
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@2: stx SYSCTL1
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rol
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sty IODAT
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bne @0
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lda __iodat
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sta IODAT
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stz _FileBlockByte
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lda #<($100-(>__BLOCKSIZE__))
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sta _FileBlockByte+1
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ply
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plx
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pla
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exit: rts
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.reloc
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__DIRECTORY_START__:
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; Entry 0 - title sprite (mandatory)
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off0=__LOADER_SIZE__+__LOADER2_SIZE__+(__DIRECTORY_END__-__DIRECTORY_START__)
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blocka=off0/__BLOCKSIZE__
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; Entry 0 - first executable
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block0=off0/__BLOCKSIZE__
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len0=__STARTUP_SIZE__+__INIT_SIZE__+__CODE_SIZE__+__DATA_SIZE__+__RODATA_SIZE__
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.byte <block0
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.word off0 & (__BLOCKSIZE__ - 1)
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.byte $88
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.word __RAM_START__
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.word len0
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__DIRECTORY_END__:
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@ -1,6 +1,6 @@
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SYMBOLS {
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__STACKSIZE__: type = weak, value = $0800; # 2k stack
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__STARTOFDIRECTORY__: type = weak, value = $019A; # start just after loader
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__STARTOFDIRECTORY__: type = weak, value = $00DF; # start just after loader
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__BLOCKSIZE__: type = weak, value = 1024; # cart block size
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__BLLHDR__: type = import;
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}
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@ -1,6 +1,6 @@
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SYMBOLS {
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__STACKSIZE__: type = weak, value = $0800; # 2k stack
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__STARTOFDIRECTORY__: type = weak, value = $019A; # start just after loader
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__STARTOFDIRECTORY__: type = weak, value = $00DF; # start just after loader
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__BLOCKSIZE__: type = weak, value = 1024; # cart block size
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__EXEHDR__: type = import;
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}
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@ -1,6 +1,6 @@
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SYMBOLS {
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__STACKSIZE__: type = weak, value = $0800; # 2k stack
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__STARTOFDIRECTORY__: type = weak, value = $019A; # start just after loader
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__STARTOFDIRECTORY__: type = weak, value = $00DF; # start just after loader
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__BLOCKSIZE__: type = weak, value = 1024; # cart block size
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__EXEHDR__: type = import;
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}
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