6 ms·

The ez80 is nice, but it's not 'orders of magnitude' more powerful than a regular z80, especially clocked at 20Mhz (the CMOS Z80C was available up to 20MHz). (

by NikkiA 2y ago

The ez80 is nice, but it's not 'orders of magnitude' more powerful than a regular z80, especially clocked at 20Mhz (the CMOS Z80C was available up to 20MHz). (The ez80 is capable of 50MHz, I'm not entirely sure why they limited it to 20Mhz in the Agon Light).

Lerc 2y ago
A just had a quick look at the ez80 it and it seems like it's pipelined, so the instructions per clock will be a lot better than the z80. A 20MHz ez80 is probably one order of magnitude improvement than the oftentimes 4MHz z80. Wikipedia says three times faster at the same clock speed. So 20*3/4=15 give or take. As an aside, last time I did napkin math estimation on the 8-bit AVR it was faster than a 68000 at the same clock speed. The 68k took 4 clocks to do register to register, AVR is mostly one clock so could do most 32 bit operations as fast or faster using multiple instructions.
- PaulHoule 2y ago
  I love AVR8 assembly so much and how AVR8 is so much better than any of the 8-bit micros in so many ways except for the small RAM size (though it does make it up in ROM)
  - Lerc 2y ago
    Me too, I made a silly fantasy console using it https://k8.fingswotidun.com/static/ide/?gist=78d170a65bc6c9ddaecefa4424915ac3 https://k8.fingswotidun.com/static/ide/?gist=78d170a65bc6c9d... In hindsight, it's not the best for emulation, I think most of the emulator time goes into extracting the bits from instructions. I really should make a translator that turns it instruction by instruction into something easier to decode.
    - wk_end 2y ago
      On a CPU with 8- or even 16-bit instructions, if at all possible (I don't know much about AVR8) it's probably better to use jump tables than to try to decode bit-wise when emulating I think.
      - PaulHoule 2y ago
        I’ve thought about making an AVR-8 emulator in AVR-8 assembly language that would let me run tiny programs out of RAM where the emulator (host) would use some of the registers and the others would be be available to the guest. This way you could upload a function over the serial port and run it. I figured it would be a good way to really master AVR-8 assembly. The ESP32 has a huge amount of potential for emulating other things, see https://github.com/breakintoprogram/agon-vdp https://github.com/breakintoprogram/agon-vdp For a display controller implemented for ESP32.
talideon 2y ago
Look, if you're going to get picky, it literally is at least an order of magnitude faster. And in addition, Hz for Hz, the eZ80 is much faster than the Z80A, which is what people would actually be comparing it to.

by NikkiA 2y ago

Lerc 2y ago

A just had a quick look at the ez80 it and it seems like it's pipelined, so the instructions per clock will be a lot better than the z80. A 20MHz ez80 is probably one order of magnitude improvement than the oftentimes 4MHz z80. Wikipedia says three times faster at the same clock speed. So 20*3/4=15 give or take. As an aside, last time I did napkin math estimation on the 8-bit AVR it was faster than a 68000 at the same clock speed. The 68k took 4 clocks to do register to register, AVR is mostly one clock so could do most 32 bit operations as fast or faster using multiple instructions.

PaulHoule 2y ago
I love AVR8 assembly so much and how AVR8 is so much better than any of the 8-bit micros in so many ways except for the small RAM size (though it does make it up in ROM)
- Lerc 2y ago
  Me too, I made a silly fantasy console using it https://k8.fingswotidun.com/static/ide/?gist=78d170a65bc6c9ddaecefa4424915ac3 https://k8.fingswotidun.com/static/ide/?gist=78d170a65bc6c9d... In hindsight, it's not the best for emulation, I think most of the emulator time goes into extracting the bits from instructions. I really should make a translator that turns it instruction by instruction into something easier to decode.
  - wk_end 2y ago
    On a CPU with 8- or even 16-bit instructions, if at all possible (I don't know much about AVR8) it's probably better to use jump tables than to try to decode bit-wise when emulating I think.
    - PaulHoule 2y ago
      I’ve thought about making an AVR-8 emulator in AVR-8 assembly language that would let me run tiny programs out of RAM where the emulator (host) would use some of the registers and the others would be be available to the guest. This way you could upload a function over the serial port and run it. I figured it would be a good way to really master AVR-8 assembly. The ESP32 has a huge amount of potential for emulating other things, see https://github.com/breakintoprogram/agon-vdp https://github.com/breakintoprogram/agon-vdp For a display controller implemented for ESP32.

talideon 2y ago

Look, if you're going to get picky, it literally is at least an order of magnitude faster. And in addition, Hz for Hz, the eZ80 is much faster than the Z80A, which is what people would actually be comparing it to.