Assembly language isn’t, but assemblers usually are. If you want a (cross-)assembler for 32-bit x86, you can build GNU as or Nasm on any reasonable platform with a C implementation, because, ultimately, bytes are bytes, and you can write
void emitd(struct buf *buf, int opcode, uint_least32_t address);
or however it looks inside your assembler without caring what sizeof(int) is (assuming CHAR_BIT is 8). By comparison, in Forth that will be
depending on the bitness of where your assembler runs, even if the machine it assembles for is exactly the same in both cases. You cannot hide the platform difference behind a typedef for uint_least32_t or whatnot, unless you’re willing to drastically reshape the entirety of Forth from inside (which it does allow).
