<s>
In	O
software	B-General_Concept
engineering	I-General_Concept
,	O
retargeting	B-Application
is	O
an	O
attribute	O
of	O
software	O
development	O
tools	O
that	O
have	O
been	O
specifically	O
designed	O
to	O
generate	O
code	O
for	O
more	O
than	O
one	O
computing	O
platform	O
.	O
</s>
<s>
A	O
retargetable	B-Application
compiler	I-Application
is	O
a	O
compiler	B-Language
that	O
has	O
been	O
designed	O
to	O
be	O
relatively	O
easy	O
to	O
modify	O
to	O
generate	O
code	O
for	O
different	O
CPU	B-Device
instruction	B-General_Concept
set	I-General_Concept
architectures	I-General_Concept
.	O
</s>
<s>
The	O
history	O
of	O
this	O
idea	O
dates	O
back	O
to	O
the	O
1950s	O
when	O
UNCOL	B-Application
was	O
proposed	O
as	O
the	O
universal	O
intermediate	O
language	O
.	O
</s>
<s>
The	O
Pascal	O
is	O
an	O
example	O
of	O
an	O
early	O
widely	O
used	O
retargetable	B-Application
compiler	I-Application
.	O
</s>
<s>
The	O
cost	O
of	O
producing	O
a	O
retargetable	B-Application
compiler	I-Application
that	O
generates	O
code	O
of	O
similar	O
quality	O
to	O
a	O
non-retargetable	O
compiler	O
(	O
i.e.	O
,	O
one	O
designed	O
to	O
only	O
ever	O
produce	O
code	O
for	O
a	O
single	O
processor	O
)	O
is	O
higher	O
because	O
it	O
is	O
not	O
possible	O
to	O
make	O
use	O
of	O
cpu	B-Device
specific	O
details	O
throughout	O
all	O
phases	O
of	O
compilation	B-Language
.	O
</s>
<s>
The	O
benefits	O
of	O
a	O
retargetable	B-Application
compiler	I-Application
is	O
that	O
the	O
total	O
cost	O
over	O
multiple	O
CPUs	B-Device
is	O
much	O
lower	O
than	O
the	O
combined	O
cost	O
of	O
many	O
individual	O
non-targetable	O
compilers	B-Language
.	O
</s>
<s>
Some	O
retargetable	B-Application
compilers	I-Application
,	O
e.g.	O
,	O
GCC	B-Application
,	O
became	O
so	O
widely	O
ported	O
and	O
developed	O
that	O
they	O
now	O
include	O
support	O
for	O
many	O
optimizations	O
and	O
machine	O
specific	O
details	O
that	O
the	O
quality	O
of	O
code	O
often	O
surpasses	O
that	O
of	O
non-retargetable	O
compilers	O
on	O
many	O
CPUs	B-Device
.	O
</s>
<s>
Unless	O
developers	O
invest	O
the	O
large	O
amount	O
of	O
time	O
necessary	O
to	O
write	O
a	O
code	O
generator	O
specifically	O
for	O
an	O
architecture	O
,	O
the	O
optimizations	O
performed	O
by	O
a	O
retargetable	B-Application
compiler	I-Application
will	O
only	O
be	O
those	O
applicable	O
to	O
generic	O
processor	O
characteristics	O
.	O
</s>
<s>
A	O
retargetable	B-Application
compiler	I-Application
is	O
a	O
kind	O
of	O
cross	B-Application
compiler	I-Application
.	O
</s>
<s>
Often	O
(	O
but	O
not	O
always	O
)	O
a	O
retargetable	B-Application
compiler	I-Application
is	O
portable	B-Architecture
(	O
the	O
compiler	B-Language
itself	O
can	O
run	O
on	O
several	O
different	O
CPUs	B-Device
)	O
and	O
self-hosting	O
.	O
</s>
<s>
Examples	O
of	O
retargetable	B-Application
compilers	I-Application
:	O
</s>
<s>
retdec	O
(	O
"	O
Retargetable	O
Decompiler	B-Application
"	O
)	O
is	O
an	O
open	B-License
source	I-License
retargetable	O
machine-code	O
decompiler	B-Application
based	O
on	O
LLVM	B-Application
.	O
</s>
<s>
The	O
decompiler	B-Application
is	O
not	O
limited	O
to	O
any	O
particular	O
target	O
architecture	O
,	O
operating	B-General_Concept
system	I-General_Concept
,	O
or	O
executable	O
file	O
format	O
:	O
</s>
<s>
Supported	O
architectures	O
(	O
currently	O
32bit	O
only	O
)	O
:	O
Intel	B-Operating_System
x86	I-Operating_System
,	O
ARM	O
,	O
MIPS	O
,	O
PIC32	O
,	O
and	O
PowerPC	O
.	O
</s>
<s>
Conversely	O
,	O
retargetable	O
assemblers	B-Language
are	O
capable	O
of	O
generating	O
object	B-Application
files	I-Application
of	O
different	O
formats	O
,	O
which	O
is	O
useful	O
in	O
porting	O
assembly	B-Language
language	I-Language
programs	O
to	O
various	O
operating	B-General_Concept
systems	I-General_Concept
that	O
run	O
on	O
the	O
same	O
CPU	B-General_Concept
architecture	I-General_Concept
(	O
such	O
as	O
Windows	B-Application
and	O
Linux	B-Application
on	O
the	O
x86	B-Operating_System
platform	O
)	O
.	O
</s>
<s>
NASM	B-Application
is	O
one	O
such	O
assembler	B-Language
.	O
</s>
