3 ms·

Not exactly "more cycle efficient", just more modern manufacturing processes. There are also 6502s available for up to 200 MHz. They are not easily available to

by avhon1 10y ago

Not exactly "more cycle efficient", just more modern manufacturing processes. There are also 6502s available for up to 200 MHz. They are not easily available to hobbyists, though - the modern DIP modules are only guaranteed up to 20MHZ, but they can be run at 25MHz.

vanderZwan 10y ago
It got a few more upgrades than just better miniaturisation: > The eZ80 has a 3-stages pipeline. Available at up to 50 MHz (2004), the performance is comparable to a Z80 clocked at 150 MHz if fast memory is used (i.e. no wait states for opcode fetches, for data, or for I/O) or even higher in some applications (a 16-bit addition is 11 times as fast as in the original). The eZ80 also supports direct continuous addressing of 16 MB of memory without a memory management unit, by extending most registers (HL, BC, DE, IX, IY, SP, and PC) from 16 to 24 bits. In order to do so, the CPU works in a Z80-compatible mode or a full 24-bit address mode. https://en.wikipedia.org/wiki/Zilog_eZ80 https://en.wikipedia.org/wiki/Zilog_eZ80 Note the pipelining, and the 24 bit ALU
cmrdporcupine 10y ago
No I believe they actually made them more cycle efficient. And the eZ80 is available to hobbyists at the high clock rates if you're willing to do SMT.
- mysterydip 10y ago
  Pardon my ignorance on the topic, but I've often wondered if it's possible to take one of these older CPU designs and "just" increase the address space and make the manufacturing process smaller (but otherwise leave the instruction set and architecture as-is) to create a modern bit version at a high clock rate for embedded or mobile use? Or is there a lot of "devil in the details" that has prevented such a thing from existing? It seems to me like upgrading one of these existing designs would be much cheaper R&D wise that you'd be able to compete very well on price for the IoT or other markets.
  - qwertyuiop924 10y ago
    While it might (I don't know) be possible to make the manufacturing process smaller, you couldn't increase the address space without effectively rewriting the entire ISA. You could use bank switching or an MMU to increase the effective address space (allowing the machine to access more RAM than it can physically address), which was done even back in the day, on pretty much every machine. >you'd be able to compete very well on price for the IoT or other markets. Why do you think that the Z80 and the 6502 (and their derivatives) are still on the market? :-D

by avhon1 10y ago

vanderZwan 10y ago

It got a few more upgrades than just better miniaturisation: > The eZ80 has a 3-stages pipeline. Available at up to 50 MHz (2004), the performance is comparable to a Z80 clocked at 150 MHz if fast memory is used (i.e. no wait states for opcode fetches, for data, or for I/O) or even higher in some applications (a 16-bit addition is 11 times as fast as in the original). The eZ80 also supports direct continuous addressing of 16 MB of memory without a memory management unit, by extending most registers (HL, BC, DE, IX, IY, SP, and PC) from 16 to 24 bits. In order to do so, the CPU works in a Z80-compatible mode or a full 24-bit address mode. https://en.wikipedia.org/wiki/Zilog_eZ80 https://en.wikipedia.org/wiki/Zilog_eZ80 Note the pipelining, and the 24 bit ALU

cmrdporcupine 10y ago

No I believe they actually made them more cycle efficient. And the eZ80 is available to hobbyists at the high clock rates if you're willing to do SMT.

mysterydip 10y ago
Pardon my ignorance on the topic, but I've often wondered if it's possible to take one of these older CPU designs and "just" increase the address space and make the manufacturing process smaller (but otherwise leave the instruction set and architecture as-is) to create a modern bit version at a high clock rate for embedded or mobile use? Or is there a lot of "devil in the details" that has prevented such a thing from existing? It seems to me like upgrading one of these existing designs would be much cheaper R&D wise that you'd be able to compete very well on price for the IoT or other markets.
- qwertyuiop924 10y ago
  While it might (I don't know) be possible to make the manufacturing process smaller, you couldn't increase the address space without effectively rewriting the entire ISA. You could use bank switching or an MMU to increase the effective address space (allowing the machine to access more RAM than it can physically address), which was done even back in the day, on pretty much every machine. >you'd be able to compete very well on price for the IoT or other markets. Why do you think that the Z80 and the 6502 (and their derivatives) are still on the market? :-D