Ah, you're making me remember back to the early-to-mid-90's when SGI (MIPS) had all these different compiler flags
so you could easily build 32-bit apps, 64-bit apps, 64-bit apps with 32-bit libraries, etc., etc.

Let's see, when did the 64-bit MIPS R4000 come out? 1991 ?

Of course, Windows was yet a few years away from leaving 16-bits -- despite having had 32-bit x86's available since 1986 or so.
And MacOS wasn't making very good use of its (pseudo) 32-bit 68000.... (available since 1978 !)