- SDCC is an open source C compiler for microcontrollers. It can output z80 assembly. However, the code is bloated and inefficient.
- z88dk is a derivative of the Small-C compiler. It is targeted specifically at the z80 line of processors and even has dedicated TI file format outputs. The code is very bloated and can be less efficient than SDCC.
- The HI-TECH Z80 C Compiler is a very old and unsupported compiler by HI-TECH that produces much better-quality code than the two compilers mentioned above (Although recent SDCC versions are able to generate code comparable to the HI-TECH C compiler). However, HI-TECH has discontinued this compiler and it is very difficult to obtain a copy. Furthermore, it is a commercial, not open-source, compiler, so using it without a license is of questionable legality.
- TIGCC is the original C compiler for 68k calculators. It is a patched version of the GNU Compiler Collection, and only supports C and 68000 assembly.
- GCC4TI is a fork of TIGCC, first published in 2009. Work on GCC4TI includes:
- fixing a number of bugs;
- performing optimizations in the library;
- integrating 2002-2005 unprocessed contributions to TIGCC: dozens of "new" functions;
- improving the build system:
- portability: in 2009, the GCC4TI build scripts were made to build out of the box on MacOS X, FreeBSD, OpenSolaris;
- reliability: GCC4TI's build scripts abort the build upon the first error instead of silently leaving users with broken builds;
- support for cross-compilation of Windows binaries from under Linux;
- increased automation;
- adding better ISO C99 compatibility;
- integrating the TI-68k Developer Utilities (formerly "TIGCC Tools Suite"), originating from TICT, as an integral part of the toolchain.