[HN Gopher] Pointers Are Complicated, Or: What's in a Byte? (2018) ___________________________________________________________________ Pointers Are Complicated, Or: What's in a Byte? (2018) Author : pcr910303 Score : 25 points Date : 2020-09-04 17:10 UTC (1 days ago) (HTM) web link (www.ralfj.de) (TXT) w3m dump (www.ralfj.de) | raphlinus wrote: | Also potentially relevant: Ralf, or I should say, Dr. Jung, | recently completed a PhD, which I'm sure will have a lot more | fascinating material for those interested in this paper. I'm | hoping to find time myself to read it, but I seem to spend too | much time on sites like Hacker News... | | https://www.ralfj.de/blog/2020/09/03/phd.html | [deleted] | teddyh wrote: | It always bothered me that C, and similar languages which are | termed "low level", aren't actually compiling to anything like | the _actual_ low level hardware anymore. The match used to be | quite close in the 1980's, but nowadays the "machine code" which | is "run" by a CPU is actally a kind of virtual byte code language | with an interpreter implemented in microcode inside the CPU. But | this byte code has flaws: For instance, this virtual machine byte | code language has little or no sense of memory caches (of any | kind), out-of-order execution, branch prediction, etc. Both the | compiler and the CPU knows (or could know) about these things, | but the compiler has no way to communicate this to the CPU other | than using this '80s style byte code which does _not_ have these | concepts. It's like talking about advanced mathematics using | nothing but words in "The Cat in the Hat" - a rather narrow | communication pipe. | | I'd always imagined that as parallelism rose, a new model of | virtual machine would rise with it, with its own "assembly" (i.e. | low level language closely tied to the machine), which would in | turn be the target of a compiler of a new parallel-by-default | high level language. Alas, this has not happened. | [deleted] | dang wrote: | Discussed at the time: | https://news.ycombinator.com/item?id=17604402 ___________________________________________________________________ (page generated 2020-09-05 23:00 UTC)