Consulting "man cc" on my Irix 6.5 (which calls the MIPSpro 7.4 compiler) I have listed the compiler flags for ABI below:
| OS | CPU | cflags |------|---------|------ | Irix | mips | o32 (same as 32) | Irix | mipsn32 | n32 | Irix | mips64 | 64 (native 64)
I compiled the good old whetstone.c for all of those above, including "o64" which wasn't even listed in man cc but just did the same as "64".
Your CPU column is a bit confusing, given that there really is a mips32 and mips64 platform now which are not the CPUs in SGI workstations, they are really IP cores used in modern SoC applications. The link you provided to MIPS32/64rev6 appears to be applicable to those newer post-SGI MIPS CPUs.
Note that when specifying -n32, the MIPSpro compiler will default to a mips4 CPU (both mips3 and mips4 can do n32), when specifying -o32 (or just -32) it will default to the mips2 CPU type (both mips1 and mips2 can do o32). For reference list of MIPS CPUs here: https://en.wikipedia.org/wiki/List_of_MIPS_architecture_processors
I guess I need to think about this a bit more.
Wolfgang