<s>
IA-32	B-Device
(	O
short	O
for	O
"	O
Intel	O
Architecture	O
,	O
32-bit	O
"	O
,	O
commonly	O
called	O
i386	B-General_Concept
)	O
is	O
the	O
32-bit	O
version	O
of	O
the	O
x86	B-Operating_System
instruction	B-General_Concept
set	I-General_Concept
architecture	I-General_Concept
,	O
designed	O
by	O
Intel	O
and	O
first	O
implemented	O
in	O
the	O
80386	B-General_Concept
microprocessor	B-Architecture
in	O
1985	O
.	O
</s>
<s>
IA-32	B-Device
is	O
the	O
first	O
incarnation	O
of	O
x86	B-Operating_System
that	O
supports	O
32-bit	O
computing	O
;	O
as	O
a	O
result	O
,	O
the	O
"	O
IA-32	B-Device
"	O
term	O
may	O
be	O
used	O
as	O
a	O
metonym	O
to	O
refer	O
to	O
all	O
x86	B-Operating_System
versions	O
that	O
support	O
32-bit	O
computing	O
.	O
</s>
<s>
Within	O
various	O
programming	O
language	O
directives	O
,	O
IA-32	B-Device
is	O
still	O
sometimes	O
referred	O
to	O
as	O
the	O
"	O
i386	B-General_Concept
"	O
architecture	O
.	O
</s>
<s>
In	O
some	O
other	O
contexts	O
,	O
certain	O
iterations	O
of	O
the	O
IA-32	B-Device
ISA	O
are	O
sometimes	O
labelled	O
i486	B-General_Concept
,	O
i586	B-General_Concept
and	O
i686	B-Device
,	O
referring	O
to	O
the	O
instruction	O
supersets	O
offered	O
by	O
the	O
80486	B-General_Concept
,	O
the	O
P5	B-General_Concept
and	O
the	O
P6	B-Device
microarchitectures	I-Device
respectively	O
.	O
</s>
<s>
These	O
updates	O
offered	O
numerous	O
additions	O
alongside	O
the	O
base	O
IA-32	B-Device
set	O
including	O
floating-point	B-Application
capabilities	I-Application
and	O
the	O
MMX	B-Architecture
extensions	I-Architecture
.	O
</s>
<s>
Intel	O
was	O
historically	O
the	O
largest	O
manufacturer	O
of	O
IA-32	B-Device
processors	O
,	O
with	O
the	O
second	O
biggest	O
supplier	O
having	O
been	O
AMD	O
.	O
</s>
<s>
During	O
the	O
1990s	O
,	O
VIA	O
,	O
Transmeta	O
and	O
other	O
chip	O
manufacturers	O
also	O
produced	O
IA-32	B-Device
compatible	O
processors	O
(	O
e.g.	O
</s>
<s>
WinChip	B-Device
)	O
.	O
</s>
<s>
In	O
the	O
modern	O
era	O
,	O
Intel	O
still	O
produced	O
IA-32	B-Device
processors	O
under	O
the	O
Intel	B-Device
Quark	I-Device
microcontroller	B-Architecture
platform	O
until	O
2019	O
;	O
however	O
,	O
since	O
the	O
2000s	O
,	O
the	O
majority	O
of	O
manufacturers	O
(	O
Intel	O
included	O
)	O
moved	O
almost	O
exclusively	O
to	O
implementing	O
CPUs	O
based	O
on	O
the	O
64-bit	O
variant	O
of	O
x86	B-Operating_System
,	O
x86-64	B-Device
.	O
</s>
<s>
x86-64	B-Device
,	O
by	O
specification	O
,	O
offers	O
legacy	O
operating	O
modes	O
that	O
operate	O
on	O
the	O
IA-32	B-Device
ISA	O
for	O
backwards	O
compatibility	O
.	O
</s>
<s>
Even	O
given	O
the	O
contemporary	O
prevalence	O
of	O
x86-64	B-Device
,	O
as	O
of	O
2018	O
,	O
IA-32	B-Device
protected	B-Application
mode	I-Application
versions	O
of	O
many	O
modern	O
operating	B-General_Concept
systems	I-General_Concept
are	O
still	O
maintained	O
,	O
e.g.	O
</s>
<s>
Microsoft	B-Application
Windows	I-Application
(	O
until	O
Windows	B-Operating_System
10	I-Operating_System
(	O
May	O
2020	O
update	O
no	O
longer	O
supports	O
IA-32	B-Device
)	O
;	O
Windows	B-Application
11	I-Application
requires	O
x86-64-compatible	O
processor	O
for	O
x86	B-Operating_System
versions	O
)	O
,	O
Windows	B-Device
Server	I-Device
(	O
until	O
Windows	B-Device
Server	I-Device
2008	I-Device
;	O
Windows	B-Device
Server	I-Device
2008	I-Device
R2	I-Device
requires	O
x86-64-compatible	O
processor	O
for	O
x86	B-Operating_System
versions	O
)	O
and	O
the	O
Debian	O
Linux	B-Application
distribution	O
.	O
</s>
<s>
In	O
spite	O
of	O
IA-32	B-Device
'	O
s	O
name	O
(	O
and	O
causing	O
some	O
potential	O
confusion	O
)	O
,	O
the	O
64-bit	O
evolution	O
of	O
x86	B-Operating_System
that	O
originated	O
out	O
of	O
AMD	O
would	O
not	O
be	O
known	O
as	O
"	O
IA-64	B-General_Concept
"	O
,	O
that	O
name	O
instead	O
belonging	O
to	O
Intel	B-General_Concept
's	I-General_Concept
Itanium	I-General_Concept
architecture	I-General_Concept
.	O
</s>
<s>
The	O
primary	O
defining	O
characteristic	O
of	O
IA-32	B-Device
is	O
the	O
availability	O
of	O
32-bit	O
general-purpose	O
processor	B-General_Concept
registers	I-General_Concept
(	O
for	O
example	O
,	O
EAX	O
and	O
EBX	O
)	O
,	O
32-bit	O
integer	O
arithmetic	O
and	O
logical	O
operations	O
,	O
32-bit	O
offsets	O
within	O
a	O
segment	O
in	O
protected	B-Application
mode	I-Application
,	O
and	O
the	O
translation	O
of	O
segmented	O
addresses	O
to	O
32-bit	O
linear	O
addresses	O
.	O
</s>
<s>
Some	O
of	O
the	O
most	O
significant	O
changes	O
(	O
relative	O
to	O
the	O
16-bit	O
286	B-General_Concept
instruction	B-General_Concept
set	I-General_Concept
)	O
are	O
described	O
below	O
.	O
</s>
<s>
All	O
general-purpose	O
registers	O
(	O
GPRs	B-General_Concept
)	O
are	O
expanded	O
from	O
16bits	O
to	O
32bits	O
,	O
and	O
all	O
arithmetic	O
and	O
logical	O
operations	O
,	O
memory-to-register	O
and	O
register-to-memory	O
operations	O
,	O
etc.	O
,	O
can	O
operate	O
directly	O
on	O
32-bit	O
integers	O
.	O
</s>
<s>
Pushes	B-Application
and	I-Application
pops	I-Application
on	O
the	O
stack	B-General_Concept
default	O
to	O
4-byte	O
strides	O
,	O
and	O
non-segmented	O
pointers	O
are	O
4	O
bytes	O
wide	O
.	O
</s>
<s>
Any	O
GPR	B-General_Concept
can	O
be	O
used	O
as	O
a	O
base	O
register	O
,	O
and	O
any	O
GPR	B-General_Concept
other	O
than	O
ESP	O
can	O
be	O
used	O
as	O
an	O
index	O
register	O
,	O
in	O
a	O
memory	O
reference	O
.	O
</s>
<s>
The	O
IA-32	B-Device
architecture	O
defines	O
a	O
48-bit	O
segmented	O
address	O
format	O
,	O
with	O
a	O
16-bit	O
segment	O
number	O
and	O
a	O
32-bit	O
offset	O
within	O
the	O
segment	O
.	O
</s>
<s>
32-bit	O
linear	O
addresses	O
are	O
virtual	O
addresses	O
rather	O
than	O
physical	O
addresses	O
;	O
they	O
are	O
translated	O
to	O
physical	O
addresses	O
through	O
a	O
page	B-General_Concept
table	I-General_Concept
.	O
</s>
<s>
In	O
the	O
80386	B-General_Concept
,	O
80486	B-General_Concept
,	O
and	O
the	O
original	B-General_Concept
Pentium	I-General_Concept
processors	O
,	O
the	O
physical	O
address	O
was	O
32	O
bits	O
;	O
in	O
the	O
Pentium	B-Device
Pro	I-Device
and	O
later	O
processors	O
,	O
the	O
Physical	B-General_Concept
Address	I-General_Concept
Extension	I-General_Concept
allowed	O
36-bit	O
physical	O
addresses	O
,	O
although	O
the	O
linear	O
address	O
size	O
was	O
still	O
32	O
bits	O
.	O
</s>
