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cc65 - a freeware C compiler for 6502 based systems
fbf3bde97c
This PR fixes the implementation of 5 illegal opcodes in the 6502, which the 6502X supports: * $93 SHA (zp),y * $9B TAS abs,y * $9C SHY abs,x * $9E SHX abs,x * $9F SHA abs,y The common denominator of the previous implementation was that it didn't correctly handle the case when the Y or X indexing induced a page crossing. In those cases, the effective address calculation of the instructions becomes truly messed up (with the high byte of the address equal to the value being written). The correctness of the implementations in this PR was verified using the 65x02 test suite, and corresponds to a (detailed) reading of the "No More Secrets" document. Stylistically, there is room for improvement in these implementations, specifically in factoring out common behavior into macros. However, for now the "explicit" coding style will suffice. It is clear enough, and we want to reach a situation soon where the sim65 code is able to pass the full '65x02' testsuite. Once we get to that point, we can refactor this code with a lot more confidence, since we will have the benefit of a working exhaustive test to make sure we don't break stuff. |
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| samples | ||
| src | ||
| targettest | ||
| test | ||
| util | ||
| .editorconfig | ||
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| Contributing.md | ||
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| README.md | ||
The cc65 cross-compiler suite
cc65 is a complete cross-development package for 65(C)02 systems, including a powerful macro assembler, a C compiler, linker, archiver, simulator and several other tools. cc65 has C and runtime library support for many of the old 6502 machines. For details look at the cc65 web site:
| Company / People | Machine / Environment |
|---|---|
| Apple | Apple II |
| Apple IIe enhanced | |
| Atari | Atari 400/800 |
| Atari 2600 | |
| Atari 5200 | |
| Atari 7800 | |
| Atari XL | |
| Lynx | |
| Tangerine | Oric Atmos |
| Eureka | Oric Telestrat |
| Acorn | BBC series |
| Commodore | C128 |
| C16 | |
| C64 | |
| CBM 510/610 | |
| PET | |
| Plus/4 | |
| VIC-20 | |
| VTech | CreatiVision |
| Commander X16 Community | Commander X16 |
| Bit Corporation | Gamate |
| Berkeley Softworks | GEOS (Apple/CBM) |
| LUnix Team | LUnix (C64) |
| Nintendo | Nintendo Entertainment System (NES) |
| Ohio Scientific | OSI C1P |
| MOS Technology, Inc. | KIM-1 |
| NEC | PC Engine (PCE) |
| Dr. Jozo Dujmović | Picocomputer (RP6502) |
| Watara | Watura/QuickShot Supervision |
| Synertek | SYM-1 |
A generic configuration to adapt cc65 to new targets is also around.
People
cc65 is originally based on the "Small C" compiler by Ron Cain and enhanced by James E. Hendrix.
Project founders
- John R. Dunning: original implementation of the C compiler and runtime library, Atari hosted.
- Ullrich von Bassewitz:
- moved Dunning's code to modern systems,
- rewrote most parts of the compiler,
- rewrote all of the runtime library.
Core team members
- Christian Groessler: Atari, Atari5200, and CreatiVision library Maintainer
- dqh: GHA help
- Greg King: all around hackery
- groepaz: CBM library, Project Maintainer
- Oliver Schmidt: Apple II library Maintainer
External contributors
- acqn: various compiler fixes
- jedeoric: Telestrat target
- jmr: compiler fixes
- karrika: Atari 7800 target
- Stephan Mühlstrasser: osic1p target
- Wayne Parham: Sym-1 target
- Dave Plummer: KIM-1 target
- rumbledethumps: Picocomputer target
(The above list is incomplete, if you feel left out - please speak up or add yourself in a PR)
For a complete list look at the full team list or the list of all contributors.
Contact
For general discussion, questions, etc subscribe to the mailing list or use the github discussions.
Some of us may also be around on IRC #cc65 on libera.chat.
Documentation
- The main Documentation for users and developers.
- Info on Contributing to the CC65 project. Please read this before working on something you want to contribute, and before reporting bugs.
- The Wiki contains some extra info that does not fit into the regular documentation.
Downloads
