<s>
GNU	B-Application
lightning	I-Application
is	O
a	O
free-software	O
library	O
for	O
generating	O
assembly	B-Language
language	I-Language
code	O
at	O
run-time	O
.	O
</s>
<s>
Version	O
2.1.3	O
,	O
released	O
in	O
September	O
2019	O
,	O
supports	O
backends	O
for	O
SPARC	B-Architecture
(	O
32-bit	O
)	O
,	O
x86	B-Operating_System
(	O
32	O
-	O
and	O
64-bit	O
)	O
,	O
MIPS	B-Device
,	O
ARM	B-Architecture
(	O
32	O
-	O
and	O
64-bit	O
)	O
,	O
ia64	B-General_Concept
,	O
HPPA	B-Device
,	O
PowerPC	B-Architecture
(	O
32-bit	O
)	O
,	O
Alpha	B-Device
,	O
S390	B-Device
and	O
RISC-V	B-Device
(	O
64-bit	O
)	O
.	O
</s>
<s>
The	O
features	O
GNU	B-Application
lightning	I-Application
provides	O
make	O
it	O
useful	O
for	O
Just-in-Time	O
Compilation	O
.	O
</s>
<s>
In	O
comparison	O
to	O
libraries	O
such	O
as	O
LLVM	B-Application
or	O
libJIT	O
,	O
GNU	B-Application
lightning	I-Application
provides	O
only	O
a	O
low-level	O
interface	O
for	O
assembling	O
from	O
a	O
standardized	O
RISC	B-Architecture
assembly	B-Language
language	I-Language
—	O
loosely	O
based	O
on	O
the	O
SPARC	B-Architecture
and	O
MIPS	B-Device
architectures	I-Device
—	O
into	O
the	O
target	O
architecture	O
's	O
machine	O
language	O
.	O
</s>
<s>
GNU	B-Application
lightning	I-Application
's	O
instruction	O
set	O
is	O
based	O
loosely	O
on	O
existing	O
RISC	B-Architecture
architectures	I-Architecture
.	O
</s>
<s>
GNU	B-Application
Smalltalk	I-Application
,	O
GNU	B-Application
Guile	I-Application
,	O
and	O
CLISP	B-Application
make	O
use	O
of	O
GNU	B-Application
lightning	I-Application
for	O
just-in-time	O
compilation	O
.	O
</s>
<s>
GNU	B-Application
lightning	I-Application
was	O
first	O
developed	O
as	O
a	O
tool	O
to	O
be	O
used	O
in	O
GNU	B-Application
Smalltalk	I-Application
's	O
dynamic	O
translator	O
from	O
bytecodes	O
to	O
native	O
code	O
.	O
</s>
<s>
GNU	B-Application
Guile	I-Application
2.9.2	O
and	O
later	O
stop	O
using	O
GNU	B-Application
lightning	I-Application
2.x	O
instead	O
their	O
own	O
fork	O
based	O
on	O
GNU	B-Application
lightning	I-Application
1.4	O
for	O
native	O
code	O
generation	O
,	O
because	O
GNU	B-Application
lightning	I-Application
2.x	O
devotes	O
more	O
complexity	O
to	O
inter-instruction	O
optimization	O
.	O
</s>
