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It's interesting why the ISAs suck or getting rotten over time (for example x86). I mean, designing an ISA is not a job for interns, it have to be developed by
by wmu 10y ago
It's interesting why the ISAs suck or getting rotten over time (for example x86). I mean, designing an ISA is not a job for interns, it have to be developed by experienced engineers. So, are all these guys have no idea what they're doing? Or, maybe some non-visible factors force certain decisions?
- jabl 10y agoLike is said in the abstract, the designers of risc-v have the advantage of 3 decades of hindsight. So they could avoid stuff that was considered good back in the day but history showed was more a disadvantage, like delay slots ot register windows. The cynic in me likes to think that existing proprietary isa's keep adding new instructions partly to keep customers on the upgrade treadmill. If you design an open ISA from a clean slate, you can make a nice orthogonal one from the get go.
- _chris_ 10y ago8086 was put together in just a few weeks, once it was clear Intel needed a "stop-gap" ISA, as their other design (432) was taking too many years to put together. And it shows. The operations they blew 1-byte instructions on is astounding (e.g., ASCII Adjust after Addition...)