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55 lines
2.2 KiB
Plaintext
55 lines
2.2 KiB
Plaintext
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SMS Boot Loader 0.91
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by Omar Cornut (Bock), for SMS Power 2001
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E-mail: omar AT miracleworld DOT net
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Web: http://www.smspower.org
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17 November 2001
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v0.90: This is a beta release version of my SMS Boot Loader.
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v0.91: Minor changes I can't remember!
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This simple program, once run on an original Sega Master System, let
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you choose and execute a program from one of the three available slots:
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+-------------------------------------------------------------+
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| System SMS1 SMS2+ MD-PBC |
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+-------------------------------------------------------------+
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| Cartridge slot yes yes yes |
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| Card slot yes no yes |
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| Expansion slot yes no no |
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+-------------------------------------------------------------+
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It has the advantage of not checking any country code or header, so
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basically it is possible to boot up an original Japanese mycard game
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(for SG-1000 or Mark III) on your US or European Master System 1.
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You can also use it to boot Brasilian 8 megabits games which are
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not supported by all models of Master System 1.
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Last but not least, using a homemade pinout converter, it would be
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possible the same way to boot up any SG-1000/SC-3000 or Mark III/SMS
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cartridge.
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The problem of course is to be able to run the actual SMS Boot Loader
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on a real system. Easiest solution is to use a development cartridge,
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but the most interesting one is to replace the machine BIOS by this
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Boot Loader.
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Things done:
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Code run from RAM is copied at 0xC700 as with the real BIOS,
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although this is not the same code, no known software rely on
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values at that location.
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Slot number is written to 0xC000 before booting.
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Things to do:
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Fix the bug when pressing button 1 on the title run cartridge
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directly (it happens sometimes).
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Detect data present on the three slots (and suggest one).
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Leave VDP Registers in the same state as the original BIOS does.
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Clear three byte variables (currently stored at 0xD00?).
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Clean and release source code.
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Enjoy!
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