<s>
In	O
computing	O
,	O
Streaming	B-General_Concept
SIMD	I-General_Concept
Extensions	I-General_Concept
(	O
SSE	O
)	O
is	O
a	O
single	B-Device
instruction	I-Device
,	I-Device
multiple	I-Device
data	I-Device
(	O
SIMD	B-Device
)	O
instruction	B-General_Concept
set	I-General_Concept
extension	O
to	O
the	O
x86	B-Operating_System
architecture	I-Operating_System
,	O
designed	O
by	O
Intel	O
and	O
introduced	O
in	O
1999	O
in	O
their	O
Pentium	B-General_Concept
III	I-General_Concept
series	O
of	O
central	B-General_Concept
processing	I-General_Concept
units	I-General_Concept
(	O
CPUs	O
)	O
shortly	O
after	O
the	O
appearance	O
of	O
Advanced	O
Micro	O
Devices	O
(	O
AMD	O
's	O
)	O
3DNow	B-General_Concept
!	I-General_Concept
.	O
</s>
<s>
SSE	O
contains	O
70	O
new	O
instructions	O
(	O
65	O
unique	O
mnemonics	O
using	O
70	O
encodings	O
)	O
,	O
most	O
of	O
which	O
work	O
on	O
single	O
precision	O
floating-point	B-Algorithm
data	O
.	O
</s>
<s>
SIMD	B-Device
instructions	O
can	O
greatly	O
increase	O
performance	O
when	O
exactly	O
the	O
same	O
operations	O
are	O
to	O
be	O
performed	O
on	O
multiple	O
data	O
objects	O
.	O
</s>
<s>
Typical	O
applications	O
are	O
digital	B-General_Concept
signal	I-General_Concept
processing	I-General_Concept
and	O
graphics	O
processing	O
.	O
</s>
<s>
Intel	O
's	O
first	O
IA-32	B-Device
SIMD	B-Device
effort	O
was	O
the	O
MMX	B-Architecture
instruction	B-General_Concept
set	I-General_Concept
.	O
</s>
<s>
MMX	B-Architecture
had	O
two	O
main	O
problems	O
:	O
it	O
re-used	O
existing	O
x87	B-Application
floating-point	B-Algorithm
registers	O
making	O
the	O
CPUs	O
unable	O
to	O
work	O
on	O
both	O
floating-point	B-Algorithm
and	O
SIMD	B-Device
data	O
at	O
the	O
same	O
time	O
,	O
and	O
it	O
only	O
worked	O
on	O
integers	O
.	O
</s>
<s>
SSE	O
floating-point	B-Algorithm
instructions	O
operate	O
on	O
a	O
new	O
independent	O
register	O
set	O
,	O
the	O
XMM	O
registers	O
,	O
and	O
adds	O
a	O
few	O
integer	O
instructions	O
that	O
work	O
on	O
MMX	B-Architecture
registers	O
.	O
</s>
<s>
SSE	O
was	O
subsequently	O
expanded	O
by	O
Intel	O
to	O
SSE2	B-General_Concept
,	O
SSE3	B-General_Concept
,	O
SSSE3	B-General_Concept
and	O
SSE4	B-General_Concept
.	O
</s>
<s>
Because	O
it	O
supports	O
floating-point	B-Algorithm
math	I-Algorithm
,	O
it	O
had	O
wider	O
applications	O
than	O
MMX	B-Architecture
and	O
became	O
more	O
popular	O
.	O
</s>
<s>
The	O
addition	O
of	O
integer	O
support	O
in	O
SSE2	B-General_Concept
made	O
MMX	B-Architecture
largely	O
redundant	O
,	O
though	O
further	O
performance	O
increases	O
can	O
be	O
attained	O
in	O
some	O
situations	O
by	O
using	O
MMX	B-Architecture
in	O
parallel	O
with	O
SSE	O
operations	O
.	O
</s>
<s>
SSE	O
was	O
originally	O
called	O
Katmai	B-General_Concept
New	I-General_Concept
Instructions	I-General_Concept
(	O
KNI	O
)	O
,	O
Katmai	O
being	O
the	O
code	O
name	O
for	O
the	O
first	O
Pentium	B-General_Concept
III	I-General_Concept
core	O
revision	O
.	O
</s>
<s>
During	O
the	O
Katmai	O
project	O
Intel	O
sought	O
to	O
distinguish	O
it	O
from	O
their	O
earlier	O
product	O
line	O
,	O
particularly	O
their	O
flagship	O
Pentium	B-General_Concept
II	I-General_Concept
.	O
</s>
<s>
It	O
was	O
later	O
renamed	O
Internet	B-General_Concept
Streaming	I-General_Concept
SIMD	I-General_Concept
Extensions	I-General_Concept
(	O
ISSE	O
)	O
,	O
then	O
SSE	O
.	O
</s>
<s>
AMD	O
eventually	O
added	O
support	O
for	O
SSE	B-General_Concept
instructions	I-General_Concept
,	O
starting	O
with	O
its	O
Athlon	O
XP	O
and	O
Duron	O
(	O
Morgan	O
core	O
)	O
processors	O
.	O
</s>
<s>
The	O
AMD64	B-Device
extensions	O
from	O
AMD	O
(	O
originally	O
called	O
x86-64	B-Device
)	O
added	O
a	O
further	O
eight	O
registers	O
XMM8	O
through	O
XMM15	O
,	O
and	O
this	O
extension	O
is	O
duplicated	O
in	O
the	O
Intel	O
64	O
architecture	O
.	O
</s>
<s>
SSE2	B-General_Concept
would	O
later	O
expand	O
the	O
usage	O
of	O
the	O
XMM	O
registers	O
to	O
include	O
:	O
</s>
<s>
Because	O
these	O
128-bit	O
registers	O
are	O
additional	O
machine	O
states	O
that	O
the	O
operating	B-General_Concept
system	I-General_Concept
must	O
preserve	O
across	O
task	B-Operating_System
switches	I-Operating_System
,	O
they	O
are	O
disabled	O
by	O
default	O
until	O
the	O
operating	B-General_Concept
system	I-General_Concept
explicitly	O
enables	O
them	O
.	O
</s>
<s>
This	O
means	O
that	O
the	O
OS	O
must	O
know	O
how	O
to	O
use	O
the	O
FXSAVE	O
and	O
FXRSTOR	O
instructions	O
,	O
which	O
is	O
the	O
extended	O
pair	O
of	O
instructions	O
that	O
can	O
save	O
all	O
x86	B-Operating_System
and	O
SSE	O
register	O
states	O
at	O
once	O
.	O
</s>
<s>
This	O
support	O
was	O
quickly	O
added	O
to	O
all	O
major	O
IA-32	B-Device
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
The	O
first	O
CPU	O
to	O
support	O
SSE	O
,	O
the	O
Pentium	B-General_Concept
III	I-General_Concept
,	O
shared	O
execution	O
resources	O
between	O
SSE	O
and	O
the	O
floating-point	B-General_Concept
unit	I-General_Concept
(	O
FPU	O
)	O
.	O
</s>
<s>
While	O
a	O
compiled	B-Language
application	O
can	O
interleave	O
FPU	O
and	O
SSE	B-General_Concept
instructions	I-General_Concept
side-by-side	O
,	O
the	O
Pentium	B-General_Concept
III	I-General_Concept
will	O
not	O
issue	O
an	O
FPU	O
and	O
an	O
SSE	O
instruction	O
in	O
the	O
same	O
clock	O
cycle	O
.	O
</s>
<s>
This	O
limitation	O
reduces	O
the	O
effectiveness	O
of	O
pipelining	B-General_Concept
,	O
but	O
the	O
separate	O
XMM	O
registers	O
do	O
allow	O
SIMD	B-Device
and	O
scalar	O
floating-point	B-Algorithm
operations	O
to	O
be	O
mixed	O
without	O
the	O
performance	O
hit	O
from	O
explicit	O
MMX/floating	O
-point	O
mode	O
switching	O
.	O
</s>
<s>
SSE	O
introduced	O
both	O
scalar	O
and	O
packed	B-Application
floating-point	B-Algorithm
instructions	O
.	O
</s>
<s>
To	O
add	O
two	O
single	O
precision	O
,	O
four-component	O
vectors	O
together	O
using	O
x86	B-Operating_System
requires	O
four	O
floating-point	B-Algorithm
addition	O
instructions	O
.	O
</s>
<s>
This	O
corresponds	O
to	O
four	O
x86	B-Operating_System
FADD	O
instructions	O
in	O
the	O
object	O
code	O
.	O
</s>
<s>
On	O
the	O
other	O
hand	O
,	O
as	O
the	O
following	O
pseudo-code	O
shows	O
,	O
a	O
single	O
128-bit	O
'	O
packed-add	O
'	O
instruction	O
can	O
replace	O
the	O
four	O
scalar	O
addition	O
instructions	O
.	O
</s>
<s>
SSE2	B-General_Concept
,	O
Willamette	O
New	O
Instructions	O
(	O
WNI	O
)	O
,	O
introduced	O
with	O
the	O
Pentium	B-General_Concept
4	I-General_Concept
,	O
is	O
a	O
major	O
enhancement	O
to	O
SSE	O
.	O
</s>
<s>
SSE2	B-General_Concept
adds	O
two	O
major	O
features	O
:	O
double-precision	O
(	O
64-bit	O
)	O
floating-point	B-Algorithm
for	O
all	O
SSE	O
operations	O
,	O
and	O
MMX	B-Architecture
integer	O
operations	O
on	O
128-bit	O
XMM	O
registers	O
.	O
</s>
<s>
In	O
the	O
original	O
SSE	O
instruction	B-General_Concept
set	I-General_Concept
,	O
conversion	O
to	O
and	O
from	O
integers	O
placed	O
the	O
integer	O
data	O
in	O
the	O
64-bit	O
MMX	B-Architecture
registers	O
.	O
</s>
<s>
SSE2	B-General_Concept
enables	O
the	O
programmer	O
to	O
perform	O
SIMD	B-Device
math	O
on	O
any	O
data	O
type	O
(	O
from	O
8-bit	O
integer	O
to	O
64-bit	O
float	B-Algorithm
)	O
entirely	O
with	O
the	O
XMM	O
vector-register	O
file	O
,	O
without	O
the	O
need	O
to	O
use	O
the	O
legacy	O
MMX	B-Architecture
or	O
FPU	O
registers	O
.	O
</s>
<s>
It	O
offers	O
an	O
orthogonal	B-General_Concept
set	I-General_Concept
of	I-General_Concept
instructions	I-General_Concept
for	O
dealing	O
with	O
common	O
data	O
types	O
.	O
</s>
<s>
SSE3	B-General_Concept
,	O
also	O
called	O
Prescott	B-General_Concept
New	I-General_Concept
Instructions	I-General_Concept
(	O
PNI	O
)	O
,	O
is	O
an	O
incremental	O
upgrade	O
to	O
SSE2	B-General_Concept
,	O
adding	O
a	O
handful	O
of	O
DSP-oriented	O
mathematics	O
instructions	O
and	O
some	O
process	O
(	O
thread	O
)	O
management	O
instructions	O
.	O
</s>
<s>
It	O
also	O
allowed	O
addition	O
or	O
multiplication	O
of	O
two	O
numbers	O
that	O
are	O
stored	O
in	O
the	O
same	O
register	O
,	O
which	O
was	O
n't	O
possible	O
in	O
SSE2	B-General_Concept
and	O
earlier	O
.	O
</s>
<s>
This	O
capability	O
,	O
known	O
as	O
horizontal	O
in	O
Intel	O
terminology	O
,	O
was	O
the	O
major	O
addition	O
to	O
the	O
SSE3	B-General_Concept
instruction	B-General_Concept
set	I-General_Concept
.	O
</s>
<s>
AMD	O
's	O
3DNow	B-General_Concept
!	I-General_Concept
</s>
<s>
SSSE3	B-General_Concept
,	O
Merom	B-General_Concept
New	I-General_Concept
Instructions	I-General_Concept
(	O
MNI	O
)	O
,	O
is	O
an	O
upgrade	O
to	O
SSE3	B-General_Concept
,	O
adding	O
16	O
new	O
instructions	O
which	O
include	O
permuting	O
the	O
bytes	O
in	O
a	O
word	O
,	O
multiplying	O
16-bit	O
fixed-point	O
numbers	O
with	O
correct	O
rounding	O
,	O
and	O
within-word	O
accumulate	O
instructions	O
.	O
</s>
<s>
SSSE3	B-General_Concept
is	O
often	O
mistaken	O
for	O
SSE4	B-General_Concept
as	O
this	O
term	O
was	O
used	O
during	O
the	O
development	O
of	O
the	O
Core	O
microarchitecture	B-General_Concept
.	O
</s>
<s>
SSE4	B-General_Concept
,	O
Penryn	O
New	O
Instructions	O
(	O
PNI	O
)	O
,	O
is	O
another	O
major	O
enhancement	O
,	O
adding	O
a	O
dot	O
product	O
instruction	O
,	O
additional	O
integer	O
instructions	O
,	O
a	O
popcnt	O
instruction	O
(	O
Population	O
count	O
:	O
count	O
number	O
of	O
bits	O
set	O
to	O
1	O
,	O
used	O
extensively	O
e.g.	O
</s>
<s>
XOP	B-General_Concept
,	O
FMA4	B-General_Concept
and	O
CVT16	B-Device
are	O
new	O
iterations	O
announced	O
by	O
AMD	O
in	O
August	O
2007	O
and	O
revised	O
in	O
May	O
2009	O
.	O
</s>
<s>
Advanced	B-General_Concept
Vector	I-General_Concept
Extensions	I-General_Concept
(	O
AVX	O
)	O
,	O
Gesher	B-General_Concept
New	I-General_Concept
Instructions	I-General_Concept
(	O
GNI	O
)	O
,	O
is	O
an	O
advanced	O
version	O
of	O
SSE	O
announced	O
by	O
Intel	O
featuring	O
a	O
widened	O
data	O
path	O
from	O
128	O
bits	O
to	O
256	O
bits	O
and	O
3-operand	O
instructions	O
(	O
up	O
from	O
2	O
)	O
.	O
</s>
<s>
AVX2	O
is	O
an	O
expansion	O
of	O
the	O
AVX	O
instruction	B-General_Concept
set	I-General_Concept
.	O
</s>
<s>
AVX-512	B-General_Concept
(	O
3.1	O
and	O
3.2	O
)	O
are	O
512-bit	O
extensions	O
to	O
the	O
256-bit	O
Advanced	B-General_Concept
Vector	I-General_Concept
Extensions	I-General_Concept
SIMD	B-Device
instructions	O
for	O
x86	B-Operating_System
instruction	B-General_Concept
set	I-General_Concept
architecture	I-General_Concept
.	O
</s>
<s>
With	O
all	O
x86	B-Operating_System
instruction	B-General_Concept
set	I-General_Concept
extensions	O
,	O
it	O
is	O
up	O
to	O
the	O
BIOS	B-Operating_System
,	O
operating	B-General_Concept
system	I-General_Concept
and	O
application	O
programmer	O
to	O
test	O
and	O
detect	O
their	O
existence	O
and	O
proper	O
operation	O
.	O
</s>
<s>
The	O
CPUID	B-Architecture
opcode	O
is	O
a	O
processor	O
supplementary	O
instruction	O
(	O
its	O
name	O
derived	O
from	O
CPU	O
IDentification	O
)	O
for	O
the	O
x86	B-Operating_System
architecture	I-Operating_System
.	O
</s>
<s>
User	O
application	O
uptake	O
of	O
the	O
x86	B-Operating_System
extensions	O
has	O
been	O
slow	O
with	O
even	O
bare	O
minimum	O
baseline	O
MMX	B-Architecture
and	O
SSE	O
support	O
(	O
in	O
some	O
cases	O
)	O
being	O
non-existent	O
by	O
applications	O
some	O
10	O
years	O
after	O
these	O
extensions	O
became	O
commonly	O
available	O
.	O
</s>
<s>
Distributed	O
computing	O
has	O
accelerated	O
the	O
use	O
of	O
these	O
extensions	O
in	O
the	O
scientific	O
community	O
—	O
and	O
many	O
scientific	O
applications	O
refuse	O
to	O
run	O
unless	O
the	O
CPU	O
supports	O
SSE2	B-General_Concept
or	O
SSE3	B-General_Concept
.	O
</s>
<s>
The	O
use	O
of	O
multiple	O
revisions	O
of	O
an	O
application	O
to	O
cope	O
with	O
the	O
many	O
different	O
sets	O
of	O
extensions	O
available	O
is	O
the	O
simplest	O
way	O
around	O
the	O
x86	B-Operating_System
extension	O
optimization	O
problem	O
.	O
</s>
<s>
Software	O
libraries	O
and	O
some	O
applications	O
have	O
begun	O
to	O
support	O
multiple	O
extension	O
types	O
hinting	O
that	O
full	O
use	O
of	O
available	O
x86	B-Operating_System
instructions	O
may	O
finally	O
become	O
common	O
some	O
5	O
to	O
15	O
years	O
after	O
the	O
instructions	O
were	O
initially	O
introduced	O
.	O
</s>
<s>
CPU-Z	B-Application
–	O
CPU	O
,	O
motherboard	O
,	O
and	O
memory	O
identification	O
utility	O
.	O
</s>
<s>
lscpu	B-Application
-	O
provided	O
by	O
the	O
util-linux	B-Application
package	O
in	O
most	O
Linux	O
distributions	O
.	O
</s>
