<s>
Libre-SOC	B-General_Concept
is	O
a	O
libre	O
soft	O
processor	O
core	O
originally	O
written	O
by	O
Luke	O
Leighton	O
and	O
other	O
contributors	O
,	O
announced	O
at	O
the	O
OpenPOWER	B-Application
Summit	O
NA	O
2020	O
.	O
</s>
<s>
It	O
adheres	O
to	O
the	O
Power	B-Architecture
ISA	I-Architecture
3.0	O
instruction	B-General_Concept
set	I-General_Concept
and	O
can	O
be	O
run	O
on	O
FPGA	B-Architecture
boards	I-Architecture
,	O
currently	O
booting	O
MicroPython	B-Language
and	O
other	O
bare-metal	O
applications	O
.	O
</s>
<s>
The	O
purpose	O
of	O
Libre-SOC	B-General_Concept
is	O
to	O
be	O
a	O
system	B-Architecture
on	I-Architecture
a	I-Architecture
chip	I-Architecture
(	O
SoC	O
)	O
with	O
3D	O
and	O
video	O
capability	O
built-in	O
as	O
part	O
of	O
the	O
Power	B-Architecture
ISA	I-Architecture
,	O
suitable	O
for	O
single-board	B-Device
computers	I-Device
,	O
netbooks	B-Device
,	O
IoT	B-Operating_System
devices	I-Operating_System
and	O
other	B-Device
small	I-Device
form	I-Device
factors	I-Device
,	O
while	O
retaining	O
a	O
completely	O
free	O
and	O
open	O
design	O
.	O
</s>
<s>
Libre-SOC	B-General_Concept
began	O
its	O
life	O
when	O
Luke	O
Leighton	O
wanted	O
there	O
to	O
be	O
a	O
completely	O
free	B-Application
and	I-Application
libre	I-Application
system	B-Architecture
on	I-Architecture
a	I-Architecture
chip	I-Architecture
offering	O
.	O
</s>
<s>
He	O
initially	O
opted	O
for	O
a	O
RISC-V	B-Device
base	O
,	O
but	O
later	O
switched	O
to	O
OpenPOWER	B-Application
when	O
that	O
seemed	O
like	O
a	O
better	O
fit	O
for	O
the	O
project	O
.	O
</s>
<s>
It	O
is	O
the	O
second	O
processor	O
written	O
from	O
scratch	O
using	O
the	O
OpenPOWER	B-Application
ISA	O
3.0	O
,	O
and	O
the	O
first	O
libre	O
core	O
that	O
is	O
completely	O
independent	O
of	O
IBM	O
.	O
</s>
<s>
While	O
being	O
developed	O
as	O
a	O
"	O
soft	B-Device
core	I-Device
"	O
Libre-SOC	B-General_Concept
will	O
be	O
fabricated	B-Architecture
in	O
180	B-Algorithm
nm	I-Algorithm
by	O
TSMC	O
's	O
"	O
Open	O
MPW	O
Shuttle	O
Program	O
"	O
through	O
Imec	O
in	O
2021	O
.	O
</s>
<s>
Libre-SOC	B-General_Concept
is	O
a	O
64-bit	B-Device
bi-endian	O
scalar	B-General_Concept
processor	I-General_Concept
core	O
,	O
implementing	O
a	O
subset	O
of	O
the	O
Power	B-Architecture
ISA	I-Architecture
3.0	O
instruction	B-General_Concept
set	I-General_Concept
.	O
</s>
<s>
It	O
has	O
32×	O
64-bit	B-Device
general	B-General_Concept
purpose	I-General_Concept
registers	I-General_Concept
.	O
</s>
<s>
It	O
uses	O
Wishbone	B-Architecture
for	O
the	O
memory	O
interface	O
.	O
</s>
<s>
The	O
Libre-SOC	B-General_Concept
core	O
will	O
be	O
a	O
hybrid	O
design	O
,	O
based	O
around	O
a	O
precise-augmented	O
version	O
of	O
the	O
historic	O
CDC	B-Device
6600	I-Device
microarchitecture	O
,	O
merging	O
traditional	O
general	O
purpose	O
,	O
vector	B-Operating_System
and	O
graphics	B-Architecture
computing	I-Architecture
into	O
a	O
single	O
execution	B-General_Concept
unit	I-General_Concept
reducing	O
complexity	O
and	O
size	O
of	O
the	O
complete	O
chip	O
as	O
well	O
as	O
simplifying	O
3D	B-Application
driver	I-Application
development	O
.	O
</s>
<s>
This	O
constitutes	O
the	O
need	O
to	O
add	O
a	O
small	O
addition	O
to	O
the	O
OpenPOWER	B-Application
instruction	B-General_Concept
set	I-General_Concept
architecture	I-General_Concept
called	O
"	O
Simple-V	O
"	O
.	O
</s>
<s>
SVP64	O
,	O
currently	O
in	O
draft	O
,	O
extends	O
OpenPOWER	B-Application
register	O
files	O
to	O
128	O
,	O
including	O
CR	O
fields	O
,	O
in	O
order	O
to	O
cope	O
with	O
modern	O
3D	O
and	O
Video	O
workloads	O
,	O
effectively	O
making	O
Libre-SOC	B-General_Concept
a	O
Vector	B-Operating_System
processor	I-Operating_System
.	O
</s>
<s>
Like	O
Microwatt	O
,	O
the	O
initial	O
development	O
was	O
done	O
in	O
around	O
three	O
months	O
,	O
included	O
the	O
entire	O
integer	B-General_Concept
processing	I-General_Concept
functionality	I-General_Concept
of	O
the	O
instruction	B-General_Concept
set	I-General_Concept
;	O
the	O
bare	O
minimum	O
to	O
make	O
it	O
compliant	O
,	O
with	O
no	O
memory	B-General_Concept
management	I-General_Concept
unit	I-General_Concept
and	O
no	O
floating-point	B-General_Concept
unit	I-General_Concept
.	O
</s>
<s>
Libre-SOC	B-General_Concept
'	O
s	O
rapid	O
development	O
is	O
,	O
like	O
Microwatt	O
,	O
down	O
to	O
the	O
significant	O
use	O
of	O
software	B-General_Concept
engineering	I-General_Concept
practices	O
including	O
thousands	O
of	O
unit	O
tests	O
and	O
by	O
Microwatt	O
source	O
code	O
as	O
a	O
reference	O
design	O
.	O
</s>
<s>
Libre-SOC	B-General_Concept
is	O
unusual	O
in	O
that	O
it	O
is	O
designed	O
using	O
,	O
a	O
Python-based	O
hardware	O
description	O
language	O
(	O
HDL	O
)	O
.	O
</s>
<s>
While	O
Libre-SOC	B-General_Concept
is	O
as	O
developed	O
as	O
a	O
libre	B-Application
software	I-Application
project	O
,	O
eventually	O
the	O
goal	O
is	O
to	O
produce	O
real	O
"	O
hard	O
"	O
hardware	O
products	O
as	O
opposed	O
to	O
the	O
"	B-Device
soft	I-Device
"	I-Device
synthesised	O
versions	O
that	O
reflects	O
the	O
actual	O
development	O
.	O
</s>
<s>
The	O
first	O
hard	O
version	O
of	O
the	O
Libre-SOC	B-General_Concept
is	O
fabricated	B-Architecture
by	O
TSMC	O
on	O
their	O
180	B-Algorithm
nm	I-Algorithm
node	O
.	O
</s>
<s>
The	O
chip	O
comprises	O
130.000	O
logic	O
gates	O
,	O
measures	O
5.5	O
×	O
5.9	O
mm2	O
and	O
will	O
be	O
packaged	B-Algorithm
in	O
a	O
128	O
pin	O
QFP	B-Algorithm
package	I-Algorithm
.	O
</s>
