4 ms·

Author was not jumping out of the paradigm here, they were deliberately misusing constructs specialised for the paradigm (br/ret). That’s like saying the toolca

Author was not jumping out of the paradigm here, they were deliberately misusing constructs specialised for the paradigm (br/ret). That’s like saying the toolcase is a specialised screw processor because you’re trying to drive nails using a screwdriver and it does not go well. And C is hardly the first or only procedural langage.

Nevermark 4y ago
No but C is a better model of most processors assembly, than most other procedural languages.
- masklinn 4y ago
  Not sure how that is relevant. The GP asserts (and bemoans) the reverse cause-and-effect.
- pjmlp 4y ago
  Only when we are talking about PDP-11. Thankfully nowadays we have Compiler Explorer supporting almost every flavour of mainstream compiled languages to dispel myths.
  - Nevermark 4y ago
    Unless you know a widely used high level language that is is a better model of newer assembly, then C would still remain “the best”, no? “Not as good lately”, doesn’t change that status without another language superseding it, right?
  - flohofwoe 4y ago
    This PDP-11 vs C thing always seems to come down to the PDP-11's auto-increment addressing modes vs C's ++ and --. Are there are any other PDP-11 features baked into C? Because this increment/decrement thing is hardly unique (the 68k CPUs had that too, and every CPU with a stack pointer also does it, some CPUs just made that a general addressing mode accessible in the instruction set. While today's compiler do a lot more transformations which can result in surprising output, it's still fairly straightforward to map C statements to CPU instructions.
    - pjmlp 4y ago
      How do you map C statements to AVX512 instructions?
      - flohofwoe 4y ago
        ...by doing the only sensible thing and use intrinsics. Auto-vectorisation is exactly where compiler optimisations stop being useful.
        pjmlp 4y ago
        On which page of ISO C can I find the intrinsics specification?
        junon 4y ago
        Not sure what your point is. There are no instruction-level parts to the standard. The C standard doesn't dictate how individual CPUs should operate.
        tsimionescu 4y ago
        The point is that C is very far away from being a "portable assembly" for any kind of modern processor. For the PDP-11 and other processors from that era, there was indeed some pretty simple 1:1 mapping between C instructions and their assembly. This has not been true for decades.
        MereInterest 4y ago
        The point is in reference to flohofwoe's earlier comment which stated "it's still fairly straightforward to map C statements to CPU instructions.". By pointing out the existence of vectorized instructions, which are entirely absent from the C standard, pjmlp was making an argument by counter-example. That while you can map C statements to CPU instructions, most compilers typically don't apply such a 1-1 mapping. The seeming non-sequitur referring to the ISO C standard was because flohofwoe responded to the rhetorical question as if it were a normal question, leading pjmlp to restate the rhetorical question in a stronger form.

Nevermark 4y ago

No but C is a better model of most processors assembly, than most other procedural languages.

masklinn 4y ago
Not sure how that is relevant. The GP asserts (and bemoans) the reverse cause-and-effect.
pjmlp 4y ago
Only when we are talking about PDP-11. Thankfully nowadays we have Compiler Explorer supporting almost every flavour of mainstream compiled languages to dispel myths.
- Nevermark 4y ago
  Unless you know a widely used high level language that is is a better model of newer assembly, then C would still remain “the best”, no? “Not as good lately”, doesn’t change that status without another language superseding it, right?
- flohofwoe 4y ago
  This PDP-11 vs C thing always seems to come down to the PDP-11's auto-increment addressing modes vs C's ++ and --. Are there are any other PDP-11 features baked into C? Because this increment/decrement thing is hardly unique (the 68k CPUs had that too, and every CPU with a stack pointer also does it, some CPUs just made that a general addressing mode accessible in the instruction set. While today's compiler do a lot more transformations which can result in surprising output, it's still fairly straightforward to map C statements to CPU instructions.
  - pjmlp 4y ago
    How do you map C statements to AVX512 instructions?
    - flohofwoe 4y ago
      ...by doing the only sensible thing and use intrinsics. Auto-vectorisation is exactly where compiler optimisations stop being useful.
      - pjmlp 4y ago
        On which page of ISO C can I find the intrinsics specification?
        junon 4y ago
        Not sure what your point is. There are no instruction-level parts to the standard. The C standard doesn't dictate how individual CPUs should operate.
        tsimionescu 4y ago
        The point is that C is very far away from being a "portable assembly" for any kind of modern processor. For the PDP-11 and other processors from that era, there was indeed some pretty simple 1:1 mapping between C instructions and their assembly. This has not been true for decades.
        MereInterest 4y ago
        The point is in reference to flohofwoe's earlier comment which stated "it's still fairly straightforward to map C statements to CPU instructions.". By pointing out the existence of vectorized instructions, which are entirely absent from the C standard, pjmlp was making an argument by counter-example. That while you can map C statements to CPU instructions, most compilers typically don't apply such a 1-1 mapping. The seeming non-sequitur referring to the ISO C standard was because flohofwoe responded to the rhetorical question as if it were a normal question, leading pjmlp to restate the rhetorical question in a stronger form.