<s>
SystemC	B-Language
is	O
a	O
set	O
of	O
C++	B-Language
classes	O
and	O
macros	O
which	O
provide	O
an	O
event-driven	B-Application
simulation	O
interface	O
(	O
see	O
also	O
discrete	B-General_Concept
event	I-General_Concept
simulation	I-General_Concept
)	O
.	O
</s>
<s>
These	O
facilities	O
enable	O
a	O
designer	O
to	O
simulate	O
concurrent	O
processes	O
,	O
each	O
described	O
using	O
plain	O
C++	B-Language
syntax	B-Application
.	O
</s>
<s>
SystemC	B-Language
processes	O
can	O
communicate	O
in	O
a	O
simulated	O
real-time	O
environment	O
,	O
using	O
signals	O
of	O
all	O
the	O
datatypes	O
offered	O
by	O
C++	B-Language
,	O
some	O
additional	O
ones	O
offered	O
by	O
the	O
SystemC	B-Language
library	O
,	O
as	O
well	O
as	O
user	O
defined	O
.	O
</s>
<s>
In	O
certain	O
respects	O
,	O
SystemC	B-Language
deliberately	O
mimics	O
the	O
hardware	O
description	O
languages	O
VHDL	B-Language
and	O
Verilog	B-Language
,	O
but	O
is	O
more	O
aptly	O
described	O
as	O
a	O
system-level	O
modeling	O
language	O
.	O
</s>
<s>
SystemC	B-Language
is	O
applied	O
to	O
system-level	O
modeling	O
,	O
architectural	O
exploration	O
,	O
performance	O
modeling	O
,	O
software	O
development	O
,	O
functional	O
verification	O
,	O
and	O
high-level	B-General_Concept
synthesis	I-General_Concept
.	O
</s>
<s>
SystemC	B-Language
is	O
often	O
associated	O
with	O
electronic	O
system-level	O
(	O
ESL	O
)	O
design	O
,	O
and	O
with	O
transaction-level	O
modeling	O
(	O
TLM	O
)	O
.	O
</s>
<s>
SystemC	B-Language
is	O
defined	O
and	O
promoted	O
by	O
the	O
Open	O
SystemC	B-Language
Initiative	O
(	O
OSCI	O
—	O
now	O
Accellera	O
)	O
,	O
and	O
has	O
been	O
approved	O
by	O
the	O
IEEE	O
Standards	O
Association	O
as	O
IEEE	O
1666-2011	O
-	O
the	O
SystemC	B-Language
Language	O
Reference	O
Manual	O
(	O
LRM	O
)	O
.	O
</s>
<s>
The	O
LRM	O
provides	O
the	O
definitive	O
statement	O
of	O
the	O
semantics	O
of	O
SystemC	B-Language
.	O
</s>
<s>
Although	O
it	O
was	O
the	O
intent	O
of	O
OSCI	O
that	O
commercial	O
vendors	O
and	O
academia	O
could	O
create	O
original	O
software	O
compliant	O
to	O
IEEE	O
1666	O
,	O
in	O
practice	O
most	O
SystemC	B-Language
implementations	O
have	O
been	O
at	O
least	O
partly	O
based	O
on	O
the	O
OSCI	O
proof-of-concept	O
simulator	O
.	O
</s>
<s>
SystemC	B-Language
has	O
semantic	O
similarities	O
to	O
VHDL	B-Language
and	O
Verilog	B-Language
,	O
but	O
may	O
be	O
said	O
to	O
have	O
a	O
syntactical	O
overhead	O
compared	O
to	O
these	O
when	O
used	O
as	O
a	O
hardware	O
description	O
language	O
.	O
</s>
<s>
On	O
the	O
other	O
hand	O
,	O
it	O
offers	O
a	O
greater	O
range	O
of	O
expression	O
,	O
similar	O
to	O
object-oriented	B-Language
design	I-Language
partitioning	I-Language
and	O
template	O
classes	O
.	O
</s>
<s>
Although	O
strictly	O
a	O
C++	B-Language
class	O
library	O
,	O
SystemC	B-Language
is	O
sometimes	O
viewed	O
as	O
being	O
a	O
language	O
in	O
its	O
own	O
right	O
.	O
</s>
<s>
Source	O
code	O
can	O
be	O
compiled	O
with	O
the	O
SystemC	B-Language
library	O
(	O
which	O
includes	O
a	O
simulation	O
kernel	O
)	O
to	O
give	O
an	O
executable	O
.	O
</s>
<s>
The	O
performance	O
of	O
the	O
OSCI	O
open-source	O
implementation	O
is	O
typically	O
less	O
optimal	O
than	O
commercial	O
VHDL/Verilog	O
simulators	O
when	O
used	O
for	O
register	O
transfer	O
level	O
simulation	O
.	O
</s>
<s>
SystemC	B-Language
version	O
1	O
included	O
common	O
hardware-description	O
language	O
features	O
such	O
as	O
structural	O
hierarchy	O
and	O
connectivity	O
,	O
clock-cycle	O
accuracy	O
,	O
delta	O
cycles	O
,	O
four-valued	B-Language
logic	I-Language
(	O
0	O
,	O
1	O
,	O
X	O
,	O
Z	O
)	O
,	O
and	O
bus-resolution	O
functions	O
.	O
</s>
<s>
SystemC	B-Language
version	O
2	O
onward	O
focused	O
on	O
communication	O
abstraction	O
,	O
transaction-level	O
modeling	O
,	O
and	O
virtual-platform	O
modeling	O
.	O
</s>
<s>
SystemC	B-Language
has	O
a	O
notion	O
of	O
a	O
container	O
class	O
called	O
a	O
module	O
.	O
</s>
<s>
Modules	O
are	O
the	O
basic	O
building	O
blocks	O
of	O
a	O
SystemC	B-Language
design	O
hierarchy	O
.	O
</s>
<s>
A	O
SystemC	B-Language
model	O
usually	O
consists	O
of	O
several	O
modules	O
which	O
communicate	O
via	O
ports	O
.	O
</s>
<s>
The	O
modules	O
can	O
be	O
thought	O
of	O
as	O
a	O
building	O
block	O
of	O
SystemC	B-Language
.	O
</s>
<s>
SystemC	B-Language
supports	O
resolved	O
and	O
unresolved	O
signals	O
.	O
</s>
<s>
SystemC	B-Language
supports	O
single-direction	O
and	O
bidirectional	O
ports	O
.	O
</s>
<s>
SystemC	B-Language
provides	O
three	O
different	O
process	O
abstractions	O
to	O
be	O
used	O
by	O
hardware	O
and	O
software	O
designers	O
.	O
</s>
<s>
Channels	O
are	O
the	O
communication	O
elements	O
of	O
SystemC	B-Language
.	O
</s>
<s>
SystemC	B-Language
introduces	O
several	O
data	O
types	O
which	O
support	O
the	O
modeling	O
of	O
hardware	O
.	O
</s>
<s>
SystemC	B-Language
traces	O
its	O
origins	O
to	O
work	O
on	O
Scenic	O
programming	O
language	O
described	O
in	O
a	O
DAC	O
1997	O
paper	O
.	O
</s>
<s>
ARM	O
Ltd.	O
,	O
CoWare	O
,	O
Synopsys	O
and	O
CynApps	O
teamed	O
up	O
to	O
develop	O
SystemC	B-Language
(	O
CynApps	O
later	O
became	O
Forte	O
Design	O
Systems	O
)	O
to	O
launch	O
it	O
first	O
draft	O
version	O
in	O
1999	O
.	O
</s>
<s>
The	O
chief	O
competitor	O
at	O
the	O
time	O
was	O
SpecC	B-Language
another	O
C	O
based	O
open	O
source	O
package	O
developed	O
by	O
UC	O
Irvine	O
personnel	O
and	O
some	O
Japanese	O
companies	O
.	O
</s>
<s>
In	O
June	O
2000	O
,	O
a	O
standards	O
group	O
known	O
as	O
the	O
Open	O
SystemC	B-Language
Initiative	O
was	O
formed	O
to	O
provide	O
an	O
industry	O
neutral	O
organization	O
to	O
host	O
SystemC	B-Language
activities	O
and	O
to	O
allow	O
Synopsys	O
 '	O
largest	O
competitors	O
,	O
Cadence	O
and	O
Mentor	O
Graphics	O
,	O
democratic	O
representation	O
in	O
SystemC	B-Language
development	O
.	O
</s>
<s>
The	O
power	O
and	O
energy	O
estimation	O
can	O
be	O
accomplished	O
in	O
SystemC	B-Language
by	O
means	O
of	O
simulations	O
.	O
</s>
<s>
Powersim	O
is	O
a	O
SystemC	B-Language
class	O
library	O
aimed	O
to	O
the	O
calculation	O
of	O
power	O
and	O
energy	O
consumption	O
of	O
hardware	O
described	O
at	O
system	O
level	O
.	O
</s>
<s>
To	O
this	O
end	O
,	O
C++	B-Language
operators	O
are	O
monitored	O
and	O
different	O
energy	O
models	O
can	O
be	O
used	O
for	O
each	O
SystemC	B-Language
data	O
type	O
.	O
</s>
