3 ms·

I wonder if ESP32 has VLIW slots and a tighter instruction packaging is possible?

• duskwuff 2y ago
  Neither Xtensa nor RISC-V are VLIW architectures.
  • restricted_ptr 2y ago
    Xtensa architecture is flexible and extendable by the user. Ability to define new instructions, hw features and VLIW configurations are some of the key features. You can find more details on the internet https://en.m.wikipedia.org/wiki/Tensilica https://en.m.wikipedia.org/wiki/Tensilica
    • jki275 2y ago
      I don't think that applies to the ESP32 family of devices. I've never heard of DSP hardware onboard them. I think the comment you're referring to is talking about the architecture in general, but not the silicon we're discussing here.
      • restricted_ptr 2y ago
        ESP32 ee.* operations in assembly look pretty much like aliases for a VLIW bundles, on the same cycle issuing loads used in the next op while also doing multiplication on other operands. This is not a minimal Xtensa. They might not have the Tensilica toolchain for redistribution to use these features freely but apparently they exposed these extensions in their assembler in some form.
  • thrtythreeforty 2y ago
    Generally speaking, this is not correct. Base Xtensa is not VLIW, but Xtensa's various vector extensions do allow VLIW instructions, collectively called "FLIX." It is doubtful that ESP32's Xtensa is VLIW-capable, though. Presumably their compiler would emit FLIX instructions if it were.