Switch to cc65 for building

.gitignore

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+src/smb.chr
+src/smbdis.o
+target/

LICENSE

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+Super Mario Bros.: Tale of the Black Koopa is published with no license. It is distributed as is in the hope that it will be useful, but WITHOUT ANY WARRANTY.
+
+---
+
+Credits:
+* Original work on Super Mario Bros.: Copyright 1985 Nintendo
+* Original work on disassembly: Copyright 2012, 2015 doppelganger
+* Additional work: Copyright 2023 Christophe Parent
+
+---
+
+Original words from doppelganger (doppelheathen@gmail.com):
+
+There are so many people I have to thank for this, and without their help this would
+probably not be possible.  So I thank all the peeps in the nesdev scene whose insight into
+the 6502 and the NES helped me learn how it works (you guys know who you are, there's no 
+way I could have done this without your help), as well as the authors of x816 and SMB 
+Utility, and the reverse-engineers who did the original Super Mario Bros. Hacking Project, 
+which I compared notes with but did not copy from.  Last but certainly not least, I thank
+Nintendo for creating this game and the NES, without which this disassembly would
+only be theory.
+
+Update: removed residual note under ChkStart label.  Thanks to ShaneM for pointing out
+the error.

README.md

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-# super-mario-bros-tale-of-the-black-koopa
+# Super Mario Bros.: Tale of the Black Koopa
 
-A hack of Super Mario Bros.
+A hack of Super Mario Bros.
+
+![Super Mario Bros.: Tale of the Black Koopa in action](/demo.png)
+
+## Usage
+
+### Requirements
+
+cc65 must be installed on your system; the oldest supported version is `2.18`. No other dependencies are required.
+
+Additionally a file containing the graphics for the original Super Mario Bros. game must be present on your system. This file is not provided.
+
+### Installing
+
+Clone this repository locally:
+
+```shell
+$ git clone https://forge.thatspaceandtime.org/ooxie/super-mario-bros-tale-of-the-black-koopa.git super_mario_bros_tale_of_the_black_koopa
+$ cd super_mario_bros_tale_of_the_black_koopa
+```
+
+Copy the graphics file:
+
+```shell
+$ cp <path_to_the_graphics_file> src/smb.chr
+```
+
+### Building
+
+To build the binary, execute:
+
+```shell
+$ cl65 -t nes -o target/smb.nes src/smbdis.asm
+```
+
+### Running
+
+To run the game, open the file `target/smb.nes` in your favorite NES emulator. Alternatively you can run it on original hardware.
+
+### Playing
+
+Refer to the original manual for Super Mario Bros.
+
+## License
+
+The source code of this project is not licensed, as the original work it is based on is not [see LICENSE](/LICENSE).