3 ms·

My main question here would be - what's the point of bringing up yet another new ISA in a world where RISC-V (which is free, open and extensible) already exists

My main question here would be - what's the point of bringing up yet another new ISA in a world where RISC-V (which is free, open and extensible) already exists and is gaining steam?

zibzab 5y ago
Isn't loongson older than riscv by more than a decade? https://en.m.wikipedia.org/wiki/Loongson https://en.m.wikipedia.org/wiki/Loongson
- kouteiheika 5y ago
  Weren't they using MIPS previously and only recently came up with the new ISA? From the Wikipedia article you've linked to: > Loongson moved to their own processor instruction set architecture (ISA) in 2021 with the release of the Loongson 3 5000 series. So, again, the question is - why just not switch to RISC-V at this point? ...unless this isn't actually very different from MIPS, and is just a renamed clone of MIPS, but they're pretending like it isn't? (Which would answer my question.)
  - native_samples 5y ago
    From reading the FAQ it appears to be MIPSish with arbitrary changes and minus the vector extension, with a riscv inspired abi. As for why bother, the goal of the project is Chinese independence from Western tech. Therefore it must be "different" but not different enough to cause much actual work or problems. Think of it as an ISA with Chinese characteristics.
  - zibzab 5y ago
    goodson _was_ mips, I assume they made it official mips at some point. so the question is basically the opposite: why riscv when MIPS already existed and was being used by third parties?
    - yjftsjthsd-h 5y ago
      > why riscv when MIPS already existed MIPS, POWER, and SPARC, AIUI - all open enough that you could make your own processor using them.
    - therealcamino 5y ago
      Well, one of the designers of RISC-V was Dave Patterson, who was also the main force behind MIPS 25-ish years earlier. So it's meant to be an improvement, a 5th generation RISC architecture, not just an equal alternative with a different license. I don't know much about the differences, but the system of standardized extensions is pretty cool and makes the same base architecture applicable to a wider range of applications. http://www.riscvbook.com/ http://www.riscvbook.com/
fandahao17 5y ago
I remember at a lecture in my school, Weiwu Hu, "Father of Godson", said RISC-V "is not well designed". Another reason is probably that since Loongson's debut in 2001, they have gained a lot of familiarity with MIPS ISA. Also, I guess Godson's main customers may be governments, who care more about security and "self-controllable" than ease of use.

My main question here would be - what's the point of bringing up yet another new ISA in a world where RISC-V (which is free, open and extensible) already exists and is gaining steam?

zibzab 5y ago

Isn't loongson older than riscv by more than a decade? https://en.m.wikipedia.org/wiki/Loongson https://en.m.wikipedia.org/wiki/Loongson

kouteiheika 5y ago
Weren't they using MIPS previously and only recently came up with the new ISA? From the Wikipedia article you've linked to: > Loongson moved to their own processor instruction set architecture (ISA) in 2021 with the release of the Loongson 3 5000 series. So, again, the question is - why just not switch to RISC-V at this point? ...unless this isn't actually very different from MIPS, and is just a renamed clone of MIPS, but they're pretending like it isn't? (Which would answer my question.)
- native_samples 5y ago
  From reading the FAQ it appears to be MIPSish with arbitrary changes and minus the vector extension, with a riscv inspired abi. As for why bother, the goal of the project is Chinese independence from Western tech. Therefore it must be "different" but not different enough to cause much actual work or problems. Think of it as an ISA with Chinese characteristics.
- zibzab 5y ago
  goodson _was_ mips, I assume they made it official mips at some point. so the question is basically the opposite: why riscv when MIPS already existed and was being used by third parties?
  - yjftsjthsd-h 5y ago
    > why riscv when MIPS already existed MIPS, POWER, and SPARC, AIUI - all open enough that you could make your own processor using them.
  - therealcamino 5y ago
    Well, one of the designers of RISC-V was Dave Patterson, who was also the main force behind MIPS 25-ish years earlier. So it's meant to be an improvement, a 5th generation RISC architecture, not just an equal alternative with a different license. I don't know much about the differences, but the system of standardized extensions is pretty cool and makes the same base architecture applicable to a wider range of applications. http://www.riscvbook.com/ http://www.riscvbook.com/

fandahao17 5y ago

I remember at a lecture in my school, Weiwu Hu, "Father of Godson", said RISC-V "is not well designed". Another reason is probably that since Loongson's debut in 2001, they have gained a lot of familiarity with MIPS ISA. Also, I guess Godson's main customers may be governments, who care more about security and "self-controllable" than ease of use.