<s>
The	O
R4600	B-Device
,	O
code-named	O
"	O
Orion	O
"	O
,	O
is	O
a	O
microprocessor	B-Architecture
developed	O
by	O
Quantum	O
Effect	O
Design	O
(	O
QED	O
)	O
that	O
implemented	O
the	O
MIPS	O
III	O
instruction	B-General_Concept
set	I-General_Concept
architecture	I-General_Concept
(	O
ISA	O
)	O
.	O
</s>
<s>
As	O
QED	O
was	O
a	O
design	O
firm	O
that	O
did	O
not	O
fabricate	O
or	O
sell	O
their	O
designs	O
,	O
the	O
R4600	B-Device
was	O
first	O
licensed	O
to	O
Integrated	O
Device	O
Technology	O
(	O
IDT	O
)	O
,	O
and	O
later	O
to	O
Toshiba	O
and	O
then	O
NKK	O
.	O
</s>
<s>
These	O
companies	O
fabricated	O
the	O
microprocessor	B-Architecture
and	O
marketed	O
it	O
.	O
</s>
<s>
The	O
R4600	B-Device
was	O
designed	O
as	O
a	O
low-end	O
workstation	O
or	O
high-end	O
embedded	B-Architecture
microprocessor	I-Architecture
.	O
</s>
<s>
Users	O
included	O
Silicon	O
Graphics	O
,	O
Inc	O
.	O
(	O
SGI	O
)	O
for	O
their	O
Indy	B-Operating_System
workstation	O
and	O
DeskStation	O
Technology	O
for	O
their	O
Windows	B-Device
NT	I-Device
workstations	I-Device
.	O
</s>
<s>
The	O
R4600	B-Device
was	O
instrumental	O
in	O
making	O
the	O
Indy	B-Operating_System
successful	O
by	O
providing	O
good	O
integer	O
performance	O
at	O
a	O
competitive	O
price	O
.	O
</s>
<s>
IDT	O
was	O
the	O
first	O
company	O
to	O
fabricate	O
and	O
ship	O
the	O
R4600	B-Device
.	O
</s>
<s>
NKK	O
announced	O
their	O
version	O
of	O
the	O
R4600	B-Device
,	O
the	O
NR4600	O
,	O
in	O
the	O
middle	O
of	O
1994	O
.	O
</s>
<s>
The	O
R4600	B-Device
was	O
a	O
simple	O
design	O
;	O
it	O
was	O
a	O
scalar	B-General_Concept
processor	I-General_Concept
,	O
issuing	O
up	O
to	O
one	O
instruction	O
per	O
cycle	O
to	O
its	O
integer	O
pipeline	O
or	O
floating-point	B-General_Concept
unit	I-General_Concept
(	O
FPU	O
)	O
.	O
</s>
<s>
The	O
FPU	O
was	O
not	O
pipelined	B-General_Concept
to	O
save	O
die	O
area	O
and	O
thus	O
cost	O
.	O
</s>
<s>
This	O
characteristic	O
severely	O
restricted	O
the	O
R4600	B-Device
's	O
floating-point	O
performance	O
,	O
but	O
did	O
not	O
impede	O
its	O
success	O
in	O
low-end	O
computers	O
or	O
embedded	O
applications	O
where	O
integer	O
performance	O
was	O
more	O
important	O
.	O
</s>
<s>
Single	O
and	O
double	O
precision	O
multiplies	O
are	O
partially	O
pipelined	B-General_Concept
and	O
have	O
an	O
eight-cycle	O
latency	O
and	O
a	O
six-cycle	O
throughput	O
.	O
</s>
<s>
The	O
R4600	B-Device
uses	O
the	O
floating-point	B-General_Concept
unit	I-General_Concept
to	O
perform	O
not	O
only	O
floating-point	O
multiply	O
and	O
divide	O
,	O
but	O
also	O
integer	O
multiply	O
and	O
divide	O
.	O
</s>
<s>
The	O
R4600	B-Device
had	O
16KB	O
two-way	O
set-associative	O
caches	B-General_Concept
for	O
instructions	O
and	O
data	O
.	O
</s>
<s>
The	O
R4600	B-Device
's	O
external	O
interface	O
did	O
not	O
support	O
multiprocessing	B-Operating_System
.	O
</s>
<s>
The	O
R4600	B-Device
needs	O
to	O
be	O
supplied	O
with	O
three	O
clock	O
signals	O
to	O
generate	O
the	O
various	O
clocks	O
.	O
</s>
<s>
The	O
R4650	B-Device
was	O
a	O
derivative	O
of	O
the	O
R4600	B-Device
announced	O
on	O
19	O
October	O
1994	O
.	O
</s>
<s>
It	O
had	O
custom	O
instructions	O
for	O
improving	O
the	O
performance	O
of	O
fixed-point	O
digital	B-General_Concept
signal	I-General_Concept
processing	I-General_Concept
(	O
DSP	O
)	O
applications	O
.	O
</s>
<s>
A	O
lower	O
cost	O
version	O
of	O
the	O
R4650	B-Device
,	O
the	O
R4640	B-Device
,	O
was	O
announced	O
on	O
27	O
November	O
1995	O
.	O
</s>
<s>
On	O
16	O
September	O
1997	O
,	O
150	O
and	O
180MHz	O
versions	O
of	O
both	O
microprocessors	B-Architecture
were	O
introduced	O
.	O
</s>
<s>
In	O
quantities	O
of	O
10	O
,	O
000	O
,	O
the	O
150	O
and	O
180MHz	O
R4640s	B-Device
were	O
priced	O
at	O
$30	O
and	O
$39	O
each	O
,	O
respectively	O
.	O
</s>
<s>
The	O
150	O
and	O
180MHz	O
R4650s	B-Device
were	O
priced	O
at	O
$60	O
and	O
$74	O
,	O
respectively	O
.	O
</s>
<s>
The	O
R4650	B-Device
was	O
also	O
available	O
in	O
133	O
and	O
167MHz	O
speeds	O
.	O
</s>
<s>
These	O
versions	O
of	O
the	O
R4600	B-Device
processor	O
were	O
used	O
in	O
some	O
arcade	O
games	O
produced	O
by	O
Namco	O
(	O
for	O
example	O
Time	B-Device
Crisis	I-Device
II	I-Device
running	O
on	O
Namco	O
's	O
System	B-Application
23	I-Application
hardware	O
)	O
.	O
</s>
<s>
The	O
R4640	B-Device
was	O
used	O
by	O
WebTV	B-Device
Networks	I-Device
for	O
their	O
WebTV	B-Device
thin	O
clients	O
for	O
the	O
first	O
couple	O
years	O
of	O
its	O
life	O
.	O
</s>
<s>
R4640	B-Device
CPUs	O
manufactured	O
by	O
IDT	O
were	O
use	O
in	O
the	O
original	O
WebTV	B-Device
Classic	I-Device
boxes	O
manufactured	O
by	O
Sony	O
and	O
Philips	O
Magnavox	O
in	O
1996	O
,	O
as	O
well	O
as	O
most	O
of	O
the	O
WebTV	B-Device
Plus	O
boxes	O
before	O
WebTV	B-Device
Networks	I-Device
switched	O
to	O
RM5230	B-General_Concept
processors	O
circa	O
late	O
1998	O
.	O
</s>
<s>
Around	O
the	O
same	O
time	O
,	O
Classic	O
boxes	O
also	O
started	O
being	O
manufactured	O
with	O
R4640	B-Device
processors	O
from	O
NKK	O
instead	O
of	O
IDT	O
.	O
</s>
<s>
The	O
R4700	B-Device
,	O
also	O
code-named	O
"	O
Orion	O
"	O
,	O
was	O
a	O
derivative	O
of	O
the	O
R4600	B-Device
ported	O
to	O
a	O
0.5µm	O
CMOS	O
process	O
.	O
</s>
<s>
The	O
R4700	B-Device
was	O
available	O
in	O
100	O
,	O
133	O
,	O
150	O
,	O
175	O
and	O
200MHz	O
versions	O
.	O
</s>
