Forum Discussion

Astrolad's avatar
Astrolad
Icon for New Contributor rankNew Contributor
6 years ago

NIOS II hex file does not match instruction set reference

When I examine a hex file created by elf2hex, the contents match the objdump file. However, the instruction set reference is quite different. For example, an I-type instruction is supposed to have th...
Astrolad's avatar
Astrolad
Icon for New Contributor rankNew Contributor
6 years ago

Ah, the answer is that I was using Architecture Revision 2 (R2) which is selected by a hidden parameter. Maybe the reason it's hidden is that it's not ready for prime time yet. There do not seem to be compatible runtime libraries. I reverted to R1 and the object matches the documentation. Too bad, I find the original instruction set bit assignments rather peculiar. R2 is much easier to decode manually.