<s>
CPMulator	B-Operating_System
is	O
a	O
program	O
to	O
emulate	O
the	O
CP/M	B-Application
operating	I-Application
system	I-Application
under	O
x86	B-Operating_System
DOS	B-Device
.	O
</s>
<s>
The	O
NEC	B-Device
V20	I-Device
processor	O
released	O
that	O
year	O
was	O
guaranteed	O
to	O
be	O
hardware	O
compatible	O
with	O
the	O
Intel	B-Device
8088	I-Device
.	O
</s>
<s>
After	O
reviewing	O
the	O
instruction	O
timing	O
of	O
the	O
math	O
operations	O
and	O
instruction	O
addressing	O
hardware	O
it	O
was	O
determined	O
it	O
could	O
slightly	O
speed	O
up	O
existing	O
8088	B-Device
based	O
IBM	B-Device
PC	I-Device
machines	O
.	O
</s>
<s>
The	O
CPU	O
was	O
socketed	O
in	O
IBM	B-Device
PC	I-Device
's	O
so	O
it	O
could	O
easily	O
be	O
replaced	O
.	O
</s>
<s>
One	O
customer	O
reported	O
his	O
monte	B-Algorithm
carlo	I-Algorithm
simulation	I-Algorithm
of	O
a	O
nuclear	O
reactor	O
was	O
so	O
much	O
faster	O
that	O
he	O
"	O
double	O
checked	O
the	O
results	O
because	O
he	O
could	O
n't	O
believe	O
it	O
was	O
finished.	O
"	O
</s>
<s>
CPMulator	B-Operating_System
was	O
developed	O
after	O
the	O
release	O
of	O
the	O
V20	O
.	O
</s>
<s>
The	O
processor	O
was	O
also	O
able	O
to	O
emulate	O
the	O
Intel	B-General_Concept
8080	I-General_Concept
instruction	O
set	O
in	O
hardware	O
.	O
</s>
<s>
CPMulator	B-Operating_System
was	O
designed	O
to	O
modify	O
CP/M	B-Application
binaries	O
to	O
make	O
them	O
run	O
as	O
if	O
native	O
8088	B-Device
DOS	B-Device
programs	O
.	O
</s>
<s>
The	O
code	O
to	O
put	O
the	O
CPU	O
in	O
emulation	B-Application
mode	O
was	O
prefixed	O
to	O
each	O
CP/M	B-Application
executable	O
.	O
</s>
<s>
Any	O
calls	O
to	O
the	O
CP/M	B-Application
operating	I-Application
system	I-Application
were	O
intercepted	O
and	O
translated	O
to	O
DOS	B-Device
operating	O
system	O
calls	O
.	O
</s>
<s>
The	O
program	O
would	O
leave	O
8080	B-General_Concept
emulation	B-Application
mode	O
,	O
make	O
the	O
operating	O
system	O
call	O
,	O
translate	O
the	O
results	O
to	O
CP/M	B-Application
standards	O
and	O
returned	O
to	O
emulation	B-Application
mode	O
and	O
continue	O
the	O
original	O
program	O
.	O
</s>
<s>
The	O
product	O
went	O
out	O
of	O
production	O
after	O
AT	B-Operating_System
class	O
machines	O
became	O
prevalent	O
and	O
NEC	O
produced	O
no	O
V	O
series	O
pin	O
for	O
pin	O
compatible	O
version	O
of	O
80286	B-General_Concept
processor	O
.	O
</s>
