Great. Did your compiler support three different architectures (four, if you include x86 in addition to x86-64) and compile and pass the test suite for all of this software?
> Projects that compile and pass their test suites include PostgreSQL (all 237 regression tests), SQLite, QuickJS, zlib, Lua, libsodium, libpng, jq, libjpeg-turbo, mbedTLS, libuv, Redis, libffi, musl, TCC, and DOOM — all using the fully standalone assembler and linker with no external toolchain. Over 150 additional projects have also been built successfully, including FFmpeg (all 7331 FATE checkasm tests on x86-64 and AArch64), GNU coreutils, Busybox, CPython, QEMU, and LuaJIT.
Writing a C compiler is not that difficult, I agree. Writing a C compiler that can compile a significant amount of real software across multiple architectures? That's significantly more non-trivial.
Frankly, I think you are exaggerating. My university had a course that required students to build a C compiler that could run the C subset of SPECint (which includes frigging Perl) and this was the usual 3 month class that was not expected to fill in 24h of your time, so I'd say 1 week sounds perfectly reasonable for someone already familiar. Good enough C for a shitton of projects is barely more complicated than writing an assembler, in fact, that is one of C's strong points (which is also the source of most of its weaknesses).
Maybe I'm underestimating the simplicity of the C language, but that doesn't sound very plausible to me.