what is the precise difference between xtensa HIFI3/4/5 and ESP32 core?

[caozilong]

HI folks:
what is the precise difference between xtensa HIFI3/4/5 and ESP32 core? after all, they are all belongs to the same ISA arch, Xtensa LX series cores, so, why HIFI has strong capability on accelation of algorithm, but it seems esp32 seems weaker than HIFI ?

thank you!

[ESP_Sprite]

HiFi3/4/5 are DSP extensions to the Xtensa core. The Xtensa cores in the ESP32 do not have these DSP extensions.

[caozilong]

So ,they are same in ISA arch? right?

[ESP_Angus]

I believe the base instruction set architecture is the same, but sharing a base instruction set doesn't mean that all CPU features are the same.

One of the main features of the xtensa architecture is that it's easily extensible with new instructions, so the DSP cores will have additional specific instructions that exist just for doing fast DSP operations. The ESP32 isn't a DSP, so it doesn't have these.

(ESP32 does have a single instruction 32-bit MAC instruction, and it's possible to do some DSP with the ESP32, but this is not the same. The HIFI cores will have instructions to do this kind of operation on vectors of values in hardware, for specific DSP computations.)