Timeline for Fastest non-emulated CP/M Z80-based computer ever built?
Current License: CC BY-SA 3.0
12 events
| when toggle format | what | by | license | comment | |
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| Nov 25, 2017 at 13:21 | comment | added | Raffzahn | @tofro Well,since they used the MSX-Engine as I/O chip, the alternative would have been to permanent disable the Z80. That would have worked and still be chaper than doing a new production chip. But why, when they could also use it as 100% compatible 'emulation' mode, instead of adding hardware to the R8000 to make it cycle compatible? | |
| Nov 25, 2017 at 13:10 | comment | added | tofro | @Raffzahn So they built two computers into one - I pretty much doubt that "comes for free", but understand what you are up to. | |
| Nov 25, 2017 at 12:17 | comment | added | Raffzahn | @tofro The Z80 within the MSX Engine comes for free andcould thus be used for Games that need 100% clock cycle accurate timing (The R800 no longer offers). A MSX-Engine is a SoC including all main components for a MSX 1 or 2 machine. So instead of making a new SoC, Panasonic reused the existing SoC but added an external R800. | |
| Nov 25, 2017 at 12:12 | comment | added | Raffzahn | @Prof.Falken The Wiki page does a nice job in explaining tat the R800 is basicly a Z800 implementation wih faster RAM access. In The TurboR it runs at 7 MHz (not 28) but due the faster RAM access (and refresh) the delivered punch per MHz is somewhere between two and four times. | |
| Nov 25, 2017 at 11:15 | comment | added | wizzwizz4♦ | @Prof.Falken The first one - I was juts asking for a benchmark of a Turbo R but other benchmarks to compare it to would also be useful. | |
| Nov 25, 2017 at 11:04 | comment | added | Prof. Falken | @wizzwizz4 sorry, I don't understand. Should I post a benchmark run on plain Z80 vs on a Turbo R? Assembler code? | |
| Nov 25, 2017 at 11:03 | comment | added | Prof. Falken | @tofro, wikipedia (and other random links) indicates the R800 is compatible with Z80, plus some more instructions. So if you could start CP/M on it, which I think you could, it would make for a pretty darn fast CP/M machine. In light of that, I suspect the extra Z80 was put there for a more compatible option to run software which would have problems on a faster CPU, or which used unofficial instructions. Commodore did a similar thing in the C128 with its half speed C64 mode (and extra Z80!). A Z80 was cheap to add. Luxor even put them in their keyboards... besides using it as main the CPU. | |
| Nov 25, 2017 at 10:59 | history | edited | Prof. Falken | CC BY-SA 3.0 |
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| Nov 25, 2017 at 10:37 | comment | added | tofro | Very much appreciate the link to MSX Turbo R computers. Didn't even know they existed - But apparently, the compatibility between R800 and Z80 can't have been that much when they put in a Z80 as well into that machine? | |
| Nov 25, 2017 at 9:56 | comment | added | wizzwizz4♦ | Welcome to Retrocomputing. It would be good if you included some benchmarks (or even some extrapolated from the "28.6 MHz Z80" value) to make it easier to compare, but this is by no means necessary as the Z80 is already enough to compare with. | |
| Nov 25, 2017 at 8:13 | review | First posts | |||
| Nov 25, 2017 at 9:56 | |||||
| Nov 25, 2017 at 8:12 | history | answered | Prof. Falken | CC BY-SA 3.0 |