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"MIPS Open" came after the RISC-V announcement, and is still currently somewhat of a joke. Half the links on the MIPS Open site are dead. I think one of the ma
by Teknoman117 6y ago
"MIPS Open" came after the RISC-V announcement, and is still currently somewhat of a joke. Half the links on the MIPS Open site are dead.
I think one of the major points for RISC-V was to avoid the possibility of patent encumbrance of the ISA so that it can be freely used for educational purposes. My computer architecture courses 5-6 years ago used MIPS I heavily. MIPS was not open at the time, but any patents for the MIPS-I ISA had long since expired.
POWER is actually open, but it is tremendously more complicated. RISC-V by comparison feels like it borrows heavily from the early MIPS ISAs, just with a relaxation of the fixed sized instructions and no architectural delay slots and a commitment to an extensible ISA (MIPS had the coprocessor interface, but I digress).
The following is my own experience - while obviously high performance CPU cores are the product of intelligent multi-person teams and many resources, I believe RISC-V is simple enough that a college student or two could implement a compliant RV32I core in an HDL course if they knew anything about computer architecture. It wouldn't be a peak performance design by any measure (if it was they should be hired by a CPU company), but I think that's actually a point of RISC-V as an educational platform AND a platform for production CPU cores.
- Symmetry 6y agoAs a teaching tool RISC-V is clearly great, as it is for companies that want to add custom instructions to their microcontrollers like NVidia or WD. But if I was looking to design a core to run user applications then to me it looks like everything is stacked in favor of Power. The complexity of the ISA is dwarfed by the complexity of a performant superscalar architecture. And to be performant in RISC-V you'd probably be needing extensive instruction fusion and variable length instructions anyways further equalizing things. And you really need the B extension which hasn't been standardized yet. Plus binary compatibility is a big concern on application cores and ISA extensions get in the way of that.
- Teknoman117 6y agoI totally agree.
- rrss 6y ago> still currently somewhat of a joke. Half the links on the MIPS Open site are dead. unsurprising given that Wave Computing shut down the project almost a year ago and subsequently declared bankruptcy.
- Teknoman117 6y agoOh I missed that, thanks for the info.