Parameter Creation

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Revision as of 20:21, 24 August 2022 by Count Zero (talk | contribs)
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WORK IN PROGRESS ... this will be hefty ...


With this lemon post $olo1870 triggered us to finally do something about Parameters.
The forum post resulted on what written below. Feel free to leave a comment on Lemon!


BBBB 02       ???            ;start of parameter will always be BB BB 02.
BBBC 29 04    AND #$04       ;02 is always followed by the address in     
                             ;memory where the code will be stored.
                             ;In this case $0429
BBBE 78       SEI            ;start of your actual loader code.
BBBF A9 08    LDA #$08       ;this varies from game to game.
BBC1 85 BA    STA $BA        ;remember you have to crack the loader first!
BBC3 A9 01    LDA #$01       ;once you have cracked the game
BBC5 85 B9    STA $B9        ;place your loader code here
BBC7 8D 19 D0 STA $D019
BBCA A9 00    LDA #$00
BBCC 85 9D    STA $9D
BBCE 8D A1 02 STA $02A1
BBD1 85 A3    STA $A3
BBD3 85 94    STA $94
BBD5 20 A5 F4 JSR $F4A5      ;point BB BB 04 here
BBD8 20 BB 05 JSR $05BB
BBDB 78       SEI 
BBDC 68       PLA 
BBDD 68       PLA 
BBDE 85 01    STA $01
BBE0 18       CLC 
BBE1 60       RTS             ;end of loader code

BBE2 BB       ???             ;BB BB 04 followed by the address in memory
BBE3 BB       ???             ;$f4a5 is located at after the code has been 
BBE4 04       ???             ;placed. In this case BB BB 04 41 04. So
BBE5 41 04    EOR ($04,X)     ;it is located at $441. This allows the cart
                              ;to replace $f4a5 with its own fast loader.

BBE7 BB       ???             ;end of parameter. 
BBE8 BB       ???             ;Always ends BB BB 00
BBE9 00       BRK