[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)
        
 (HTM) web link (www.vogons.org)
 (TXT) 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)