Re: Rom header hacking basics? (The Dumper)

-------------------------------------------------------------------------------
4. FILE HEADER
-------------------------------------------------------------------------------
   1) CREATED BY JSI/FRONT FAREAST.
   2) 512 BYTES LENGTH. (ONE SSECTOR)
   3) BYTE
       0   - LOW BYTE OF 8K-BYTES PAGE COUNTS.
       1   - HIGH BYTE OF 8K-BYTES PAGE COUNTS.
       2   - EMULATION MODE SELECT
             BIT 76543210
                 X        : 1=RUN IN MODE 0. (JUMP $8000)
                  X       : 0=LAST FILE OF THE GAME. (MULTI FILE LOADING)
                   X      : 0=MODE 1, 1=MODE 2. (SRAM MAPPING)
                    X     : 0=MODE 20, 1=MODE 21. (DRAM MAPPING)
                     XX   : 0=SRAM OFF, 1=SRAM 16K, 2=SRAM 64K, 3=SRAM 256K
                       X  : 0=RUN IN MODE 3, 1=RUN IN MODE 2. (JMP RESET)
                        X : 0=DISABLE, 1=ENABLE. (EXTERNAL CARTRIDGE MEMORY
                                                  IMAGE AT BANK 20-5F, A0-DF
                                                  IN SYSTEM MODE 2, 3)
       3-7 - RESERVED. (SHOULD BE '00')
       8   - FILE ID CODE 1. (SHOULD BE 'AA')
       9   - FILE ID CODE 2. (SHOULD BE 'BB')
       10  - CHECK THIS BYTE IF ID 1 AND 2 MATCH.
             '02': MAGIC GRIFFIN GAME FILE. (PC ENGINE)
             '03': MAGIC GRIFFIN SRAM DATA FAILE.
             '04': SWC&SMC GAME FILE. (SUPER MAGICOM)
             '05': SWC&SMC PASSWORD, SRAM DATA, SAVER DATA FILE.
             '06': SMD GAME FILE. (MEGA DRIVE)
             '07': SMD SRAM DATA FILE.
       11-511 - RESERVED. (SHOULD BE '00')

Just used the 'pre' html tag for pre-formatted text :)

Anyways, I still don't really get it...

1) WTF is a 8K Page count??
2) What is 'Mode 0', 'Mode 1', 'Mode 2', 'Mode 3', 'Mode 20' and 'Mode 21'? How do you find out if a game uses one of them? Or are they Console specific Modes (like one different mode for Megadrive, SNES and PC-Engine games)?
3) What is 'external cartridge memory'?

-- Matthias

• Re: Rom header hacking basics? (The Dumper) The Dumper 19:52:36 05/23/01 (0) responses

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Message	> Well, here's how it should look like... > <pre>------------------------------------------------------------------------------- > 4. FILE HEADER > ------------------------------------------------------------------------------- > 1) CREATED BY JSI/FRONT FAREAST. > 2) 512 BYTES LENGTH. (ONE SSECTOR) > 3) BYTE > 0 - LOW BYTE OF 8K-BYTES PAGE COUNTS. > 1 - HIGH BYTE OF 8K-BYTES PAGE COUNTS. > 2 - EMULATION MODE SELECT > BIT 76543210 > X : 1=RUN IN MODE 0. (JUMP $8000) > X : 0=LAST FILE OF THE GAME. (MULTI FILE LOADING) > X : 0=MODE 1, 1=MODE 2. (SRAM MAPPING) > X : 0=MODE 20, 1=MODE 21. (DRAM MAPPING) > XX : 0=SRAM OFF, 1=SRAM 16K, 2=SRAM 64K, 3=SRAM 256K > X : 0=RUN IN MODE 3, 1=RUN IN MODE 2. (JMP RESET) > X : 0=DISABLE, 1=ENABLE. (EXTERNAL CARTRIDGE MEMORY > IMAGE AT BANK 20-5F, A0-DF > IN SYSTEM MODE 2, 3) > 3-7 - RESERVED. (SHOULD BE '00') > 8 - FILE ID CODE 1. (SHOULD BE 'AA') > 9 - FILE ID CODE 2. (SHOULD BE 'BB') > 10 - CHECK THIS BYTE IF ID 1 AND 2 MATCH. > '02': MAGIC GRIFFIN GAME FILE. (PC ENGINE) > '03': MAGIC GRIFFIN SRAM DATA FAILE. > '04': SWC&SMC GAME FILE. (SUPER MAGICOM) > '05': SWC&SMC PASSWORD, SRAM DATA, SAVER DATA FILE. > '06': SMD GAME FILE. (MEGA DRIVE) > '07': SMD SRAM DATA FILE. > 11-511 - RESERVED. (SHOULD BE '00')</pre> > Just used the 'pre' html tag for pre-formatted text :) > Anyways, I still don't really get it... > 1) WTF is a 8K Page count?? > 2) What is 'Mode 0', 'Mode 1', 'Mode 2', 'Mode 3', 'Mode 20' and 'Mode 21'? How do you find out if a game uses one of them? Or are they Console specific Modes (like one different mode for Megadrive, SNES and PC-Engine games)? > 3) What is 'external cartridge memory'? > -- Matthias
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