[comp.sys.m68k] The 4.77MHz PC isn't 8086 based

andrew@frip.gwd.tek.com (Andrew Klossner) (02/06/88)

>> Basically, I agree that a 68000 probably cannot emulate an 8086
>> without some sort of hardware assistance ...

> Wanna bet?  I have in front of me a beast named 'PC-ditto' for my Atari
> ST.... runs most IBM PC software about as fast as the original 4.77 
> MHz (?) PC did ...

The original 4.77MHz PC was based on an 8088, not an 8086, and the note
to which you responded quoted an emulator that is faster than the
original PC in the very next paragraph.

  -=- Andrew Klossner   (decvax!tektronix!tekecs!andrew)       [UUCP]
                        (andrew%tekecs.tek.com@relay.cs.net)   [ARPA]

finkel@TAURUS.BITNET (02/09/88)

> >> Basically, I agree that a 68000 probably cannot emulate an 8086
> >> without some sort of hardware assistance ...
>
> > Wanna bet?  I have in front of me a beast named 'PC-ditto' for my Atari
> > ST.... runs most IBM PC software about as fast as the original 4.77
> > MHz (?) PC did ...
>
> The original 4.77MHz PC was based on an 8088, not an 8086, and the note
> to which you responded quoted an emulator that is faster than the
> original PC in the very next paragraph.
>
>   -=- Andrew Klossner   (decvax!tektronix!tekecs!andrew)       [UUCP]
>                         (andrew%tekecs.tek.com@relay.cs.net)   [ARPA]
Eeexxxcccuuussseee   mmmeee!!!
According to what I know, PC-ditto runs 5 to 20 times slower than a normal
PC. From my experience with a similar program for the Amiga called The Amiga
Transformer, which is also about 5 times slower, it is possible to run
programs like kermit 2.29, which is IO bounded, and doesn't have a lot of
computations, but is rather limited by the speed the user can type. The
program can ahndle 1200 baud easily.
realtime 8088 simulation is available on Unix with the Soft PC product.
I have also read about a translation program from MS-DOS to Unix. It's a
very intelegent program which analyses the program flow and decides which
flags should be computed for each instruction, thereby gaining more speed.
the translator also detects all the instruction that write to IO areas, and
can replace such operations with the corresponding system calls.
I forgot the name of the program, but I cann look it up. it's available for
68020 Unix machines, and for SPARC ( if I'm not wrong ).

Udi Finkelstein
                  finkel@math.tau.ac.il
         or       finkel@taurus.BITNET     ( which is the same ).