3 ms·

> I am sorry but saying that RISC-V is a winner in code density is beyond ridiculous. You have no idea what you're talking about. I've worked on designs with b

by audunw 5y ago

> I am sorry but saying that RISC-V is a winner in code density is beyond ridiculous. You have no idea what you're talking about. I've worked on designs with both ARM and RISC-V cores. The RISC-V code outperforms the ARM core, with smaller gate count, and has similar or higher code density in real world code, depending on the extensions supported. The only way you get much lower code density is without the C extension, but I haven't seen it not implemented in a real-world commercial core, and if it wasn't, I'm sure there was because of a benefit (FPGAs sometimes use ultra-simple cores for some tasks, and don't always care about instruction throughput or density) It should be said that my experience is in embedded, so yes, it's unsafe code. But the embedded use-case is also the most mature. I wouldn't be surprised if extensions that help with safer programming languages would be added for desktop/server class CPUs, if they haven't already (I haven't followed the development of the spec that closely recently)

dataflow 5y ago
>> RISC-V has an acceptable code size only for unsafe code > You have no idea what you're talking about. > It should be said that my experience is in embedded, so yes, it's unsafe code. Just going based off your reply it certainly sounds like they had at least some idea what they were talking about? In which case omitting that sentence would probably help.
voz_ 5y ago
Textbook example of the kind of hostility and close-mindedness that is creeping into our beloved site. Why are we dick measuring? why are we comparing experience like this? so much "I" "I" "I"... I have no horse in the technical race here, but I certainly am put off from reading what should be an intellectually stimulating discussion by the nature of replies like this.
- snvzz 5y ago
  It was likely instigated by its parent trying to inflate himself by giving themselves some credentials, to try and give their voice more weight. All of it, pretty sad, but I believe we should focus on the technical arguments and try to put everything else aside in order to re-conduct the discussion somewhere more useful.
- flatiron 5y ago
  Oh no. We don’t maintain this site with these types of comments no matter your feelings. It’s the internet. Don’t get heated!
  - macintux 5y ago
    > Be kind. Don't be snarky. Have curious conversation; don't cross-examine. Please don't fulminate. Please don't sneer, including at the rest of the community. > Comments should get more thoughtful and substantive, not less, as a topic gets more divisive. > When disagreeing, please reply to the argument instead of calling names. "That is idiotic; 1 + 1 is 2, not 3" can be shortened to "1 + 1 is 2, not 3." https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
- wott 5y ago
  Somehow I find it refreshing to see flamewars about ISAs, for I hadn't seen any in the last 15 years (at least). It makes me feel young again. :-)
zozbot234 5y ago
Memory-safe programming does not need any special ISA extension compared to traditional, C-like unsafe code. Even the practical overhead of bounds- and overflow checking is all about how it impedes the applicability of optimizations, not about the checks themselves.
- saagarjha 5y ago
  It doesn't need them, but having hardware checks is generally more performant than having software ones.
GoblinSlayer 5y ago
RISC-V doesn't hinder safe code, that was an incorrect claim. Bound checks are done with one instruction - bltu for slices, bgeu for indexes. On intel processor you need cmp+jb pair for this. The linked message is about carry propagation pattern used in gmp. AIU optimized bignum algorithms accumulate carry bits and propagate them in bulk and don't benefit from optimal one bit at a time carry propagation pattern.

by audunw 5y ago

dataflow 5y ago

>> RISC-V has an acceptable code size only for unsafe code > You have no idea what you're talking about. > It should be said that my experience is in embedded, so yes, it's unsafe code. Just going based off your reply it certainly sounds like they had at least some idea what they were talking about? In which case omitting that sentence would probably help.

voz_ 5y ago

Textbook example of the kind of hostility and close-mindedness that is creeping into our beloved site. Why are we dick measuring? why are we comparing experience like this? so much "I" "I" "I"... I have no horse in the technical race here, but I certainly am put off from reading what should be an intellectually stimulating discussion by the nature of replies like this.

snvzz 5y ago
It was likely instigated by its parent trying to inflate himself by giving themselves some credentials, to try and give their voice more weight. All of it, pretty sad, but I believe we should focus on the technical arguments and try to put everything else aside in order to re-conduct the discussion somewhere more useful.
flatiron 5y ago
Oh no. We don’t maintain this site with these types of comments no matter your feelings. It’s the internet. Don’t get heated!
- macintux 5y ago
  > Be kind. Don't be snarky. Have curious conversation; don't cross-examine. Please don't fulminate. Please don't sneer, including at the rest of the community. > Comments should get more thoughtful and substantive, not less, as a topic gets more divisive. > When disagreeing, please reply to the argument instead of calling names. "That is idiotic; 1 + 1 is 2, not 3" can be shortened to "1 + 1 is 2, not 3." https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
wott 5y ago
Somehow I find it refreshing to see flamewars about ISAs, for I hadn't seen any in the last 15 years (at least). It makes me feel young again. :-)

zozbot234 5y ago

Memory-safe programming does not need any special ISA extension compared to traditional, C-like unsafe code. Even the practical overhead of bounds- and overflow checking is all about how it impedes the applicability of optimizations, not about the checks themselves.

saagarjha 5y ago
It doesn't need them, but having hardware checks is generally more performant than having software ones.

GoblinSlayer 5y ago

RISC-V doesn't hinder safe code, that was an incorrect claim. Bound checks are done with one instruction - bltu for slices, bgeu for indexes. On intel processor you need cmp+jb pair for this. The linked message is about carry propagation pattern used in gmp. AIU optimized bignum algorithms accumulate carry bits and propagate them in bulk and don't benefit from optimal one bit at a time carry propagation pattern.