[HN Gopher] MartyPC, cycle accurate IBM PC/XT emulator
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MartyPC, cycle accurate IBM PC/XT emulator
 
Author : nbaksalyar
Score  : 86 points
Date   : 2023-07-03 17:01 UTC (5 hours ago)
 
web link (www.vogons.org)
w3m dump (www.vogons.org)
 
| viler wrote:
| The author has done a superb job here. Not only does it have a
| cycle-exact Intel 8088 implementation (matched with disassembled
| microcode timings and hardware-verified) - it does the same for
| the CGA, where the dot clock is 3 times the CPU clock
| frequency... and it correctly represents the monitor's output,
| overscan included, which most other PC emulators have never
| bothered to do.
| 
| And those debugging tools are something else, too!
 
  | sedatk wrote:
  | So, this should run 8088MPH demo without issues? (Nevermind,
  | there is a link to it on the page :))
 
| mmastrac wrote:
| I was curious about this...
| 
| "8253 PIT - Recently rewritten after microcontroller-based
| research. At least one previously undocumented feature
| discovered. Accurate enough for PCM audio."
| 
| ... and it turns out that it's this ...
| 
| https://github.com/dbalsom/martypc/blob/main/core/src/device...
| // If the counting element was reloaded between load of LSB and
| MSB, it is an incomplete load.                             //
| Reload the counting element again when we get the MSB.
| // Note: This is completely undocumented behavior
 
| autoexec wrote:
| My first computer was a hand me down IBM XT. No hard drive, but
| two 5.25 floppy drives. I never tried running The Secret of
| Monkey Island on it, but it did run games like Night Mission
| Pinball. Paratrooper. and JBIRD.
 
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(page generated 2023-07-03 23:00 UTC)