gcc-ia16

Mainstream GCC has never supported 16-bit code on x86, only 32-bit However, there is (at least one) fork which adds 16-bit code support, see https://github.com/tkchia/gcc-ia16 I don't think the GCC maintainers have ever or will ever want to support 16-bit x86, because it is so limited, and adds a lot of messy corner cases, and nowadays is really only of hobbyist/retrocomputing interest. Maybe there is some 16-bit x86 embedded system still being maintained–there were military spec versions of the 8086, and possibly some weapons system, aircraft, satellite, etc, still in use contains one. But I doubt they'd have any interest in adopting a 16-bit GCC – they'd already have some proprietary compiler they'd been using for decades, switching now would add a lot of risk, very late in the life of a legacy system, for no tangible benefit

These days there is also a 16-bit GCC port to DOS (https://github.com/tkchia/gcc-ia16). I never encountered one of those back in the day? I think the compiler itself does not run in 16-bit DOS though. Anyone interested in compiling for DOS (32-bit or 16-bit) should also check out Free Pascal.

TK Chia and others have been working on adding DOS C/C++ compiler-isms to GCC as well as improving the the codegen to make it more hospitable for DOS apps. So far, the FreeDOS kernel compilable by gcc-ia16. https://github.com/tkchia/gcc-ia16

I recommend you to look here: https://github.com/andrewwutw/build-djgpp and https://github.com/tkchia/gcc-ia16 Using that DJGPP toolchain, I've have developed some DOS games in the last couple of years (one of those, using C++14 and EASTL, no less!).

tkchia [0] has been working on getting gcc to emit 16-bit clean code (no 32-bit code prefixes) along with ancillary tooling like binutils, a couple different libc's, and some of the things you'd expect from a 16-bit x86 C compiler like far pointers and DOS-specific libc functions [0]. The use case is to build the FreeDOS Kernel and ELKS 16-bit Linux Kernel from a 32-bit or 64-bit Linux system. [0] https://github.com/tkchia/gcc-ia16 [1] https://github.com/tkchia/build-ia16/releases