The 8501 also has much shorter instructions than a modern 32-bit processor, making it much easier. The original Brainfuck compiler was something like 240 bytes on m68k, with file format and operating system overhead, and generation of valid executable files, not just compiled code in memory.
You're entirely missing the point. First, the original Brainfuck compiler wasn't written in C, it was written in Assembly in order to get it small enough. And yes, it was a demonstration of something small and compact.
Here is the original implementation: http://aminet.net/package.php?package=dev/lang/brainfuck-2.lha
Note that the description is "240 byte compiler. Fun, with src." The README further states:
> Yes, I squeezed another ridiculous 56 bytes out of the compiler. They have their price, though: The new compiler requires OS 2.0, operates on a byte array instead of longwords, and generates executables that are always 64K in size. Apart from that the language hasn't changed. Again: *** OS 2.0 required for the compiler and the compiled programs ***
The interpreter works fine under any OS version. And yes, thanks to Chris Schneider for his ideas how to make the compiler shorter.