<s>
The	O
Clipper	B-General_Concept
architecture	I-General_Concept
is	O
a	O
32-bit	O
RISC-like	O
instruction	B-General_Concept
set	I-General_Concept
architecture	I-General_Concept
designed	O
by	O
Fairchild	O
Semiconductor	O
.	O
</s>
<s>
The	O
architecture	O
never	O
enjoyed	O
much	O
market	O
success	O
,	O
and	O
the	O
only	O
computer	O
manufacturers	O
to	O
create	O
major	O
product	O
lines	O
using	O
Clipper	O
processors	O
were	O
Intergraph	O
and	O
High	B-Operating_System
Level	I-Operating_System
Hardware	I-Operating_System
,	O
although	O
Opus	O
Systems	O
offered	O
a	O
product	O
based	O
on	O
the	O
Clipper	O
as	O
part	O
of	O
its	O
Personal	O
Mainframe	O
range	O
.	O
</s>
<s>
The	O
first	O
processors	O
using	O
the	O
Clipper	B-General_Concept
architecture	I-General_Concept
were	O
designed	O
and	O
sold	O
by	O
Fairchild	O
,	O
but	O
the	O
division	O
responsible	O
for	O
them	O
was	O
subsequently	O
sold	O
to	O
Intergraph	O
in	O
1987	O
;	O
Intergraph	O
continued	O
work	O
on	O
Clipper	O
processors	O
for	O
use	O
in	O
its	O
own	O
systems	O
.	O
</s>
<s>
The	O
Clipper	B-General_Concept
architecture	I-General_Concept
used	O
a	O
simplified	O
instruction	B-General_Concept
set	I-General_Concept
compared	O
to	O
earlier	O
CISC	B-Architecture
architectures	I-Architecture
,	O
but	O
it	O
did	O
incorporate	O
some	O
more	O
complicated	O
instructions	O
than	O
were	O
present	O
in	O
other	O
contemporary	O
RISC	B-Architecture
processors	I-Architecture
.	O
</s>
<s>
These	O
instructions	O
were	O
implemented	O
in	O
a	O
so-called	O
Macro	O
Instruction	O
ROM	B-Device
within	O
the	O
Clipper	O
CPU	O
.	O
</s>
<s>
This	O
scheme	O
allowed	O
the	O
Clipper	O
to	O
have	O
somewhat	O
higher	O
code	O
density	O
than	O
other	O
RISC	B-Architecture
CPUs	O
.	O
</s>
<s>
The	O
C400	O
processor	O
combined	O
two	O
key	O
architectural	O
techniques	O
to	O
achieve	O
a	O
new	O
level	O
of	O
performance	O
—	O
superscalar	B-General_Concept
instruction	O
dispatch	O
and	O
superpipelined	B-General_Concept
operation	O
.	O
</s>
<s>
While	O
many	O
processors	O
of	O
the	O
time	O
used	O
either	O
superscalar	B-General_Concept
instruction	O
dispatch	O
or	O
superpipelined	B-General_Concept
operation	O
,	O
the	O
Clipper	O
C400	O
was	O
the	O
first	O
processor	O
to	O
use	O
both	O
.	O
</s>
<s>
The	O
C100	O
and	O
C300	O
consist	O
of	O
three	O
chips	O
:	O
one	O
central	O
processing	O
unit	O
containing	O
both	O
an	O
integer	O
unit	O
and	O
a	O
floating	B-General_Concept
point	I-General_Concept
unit	I-General_Concept
,	O
and	O
two	O
cache	B-General_Concept
and	O
memory	B-General_Concept
management	I-General_Concept
units	O
(	O
CAMMUs	O
)	O
,	O
one	O
responsible	O
for	O
data	O
and	O
one	O
for	O
instructions	O
.	O
</s>
<s>
The	O
CAMMUs	O
contained	O
caches	O
,	O
translation	B-Architecture
lookaside	I-Architecture
buffers	I-Architecture
,	O
and	O
support	O
for	O
memory	B-General_Concept
protection	I-General_Concept
and	O
virtual	B-Architecture
memory	I-Architecture
.	O
</s>
<s>
The	O
C400	O
consists	O
of	O
four	O
basic	O
units	O
:	O
an	O
integer	O
CPU	O
,	O
an	O
FPU	O
,	O
an	O
MMU	O
,	O
and	O
a	O
cache	B-General_Concept
unit	O
.	O
</s>
<s>
The	O
initial	O
version	O
used	O
one	O
chip	O
each	O
for	O
the	O
CPU	O
and	O
FPU	O
and	O
discrete	O
elements	O
for	O
the	O
MMU	O
and	O
cache	B-General_Concept
unit	O
,	O
but	O
in	O
later	O
versions	O
the	O
MMU	O
and	O
cache	B-General_Concept
unit	O
were	O
combined	O
into	O
one	O
CAMMU	O
chip	O
.	O
</s>
<s>
The	O
Clipper	O
was	O
a	O
load/store	B-Architecture
architecture	I-Architecture
,	O
where	O
arithmetic	O
operations	O
could	O
only	O
specify	O
register	O
or	O
immediate	O
operands	O
.	O
</s>
<s>
Intergraph	O
sold	O
several	O
generations	O
of	O
Clipper	O
systems	O
,	O
including	O
both	O
servers	O
and	O
workstations	B-Device
.	O
</s>
<s>
These	O
systems	O
included	O
the	O
InterAct	O
,	O
InterServe	O
,	O
and	O
InterPro	O
product	O
lines	O
and	O
were	O
targeted	O
largely	O
at	O
the	O
CAD	B-Application
market	O
.	O
</s>
<s>
Fairchild	O
promoted	O
the	O
CLIX	O
operating	O
system	O
,	O
a	O
version	O
of	O
UNIX	B-Operating_System
System	I-Operating_System
V	I-Operating_System
,	O
for	O
use	O
with	O
the	O
Clipper	O
.	O
</s>
<s>
Intergraph	O
did	O
work	O
on	O
a	O
version	O
of	O
Microsoft	B-Device
Windows	I-Device
NT	I-Device
for	O
Clipper	O
systems	O
and	O
publicly	O
demonstrated	O
it	O
,	O
but	O
this	O
effort	O
was	O
canceled	O
before	O
release	O
.	O
</s>
<s>
Intergraph	O
decided	O
to	O
discontinue	O
the	O
Clipper	O
line	O
and	O
began	O
selling	O
x86	B-Operating_System
systems	O
with	O
Windows	B-Device
NT	I-Device
instead	O
.	O
</s>
