<s>
ACL2	B-Application
(	O
"	O
A	O
Computational	O
Logic	O
for	O
Applicative	B-Application
Common	B-Language
Lisp	I-Language
"	O
)	O
is	O
a	O
software	O
system	O
consisting	O
of	O
a	O
programming	O
language	O
,	O
an	O
extensible	O
theory	O
in	O
a	O
first-order	O
logic	O
,	O
and	O
an	O
automated	B-Application
theorem	I-Application
prover	I-Application
.	O
</s>
<s>
ACL2	B-Application
is	O
designed	O
to	O
support	O
automated	O
reasoning	O
in	O
inductive	O
logical	O
theories	O
,	O
mostly	O
for	O
software	O
and	O
hardware	O
verification	O
.	O
</s>
<s>
The	O
input	O
language	O
and	O
implementation	O
of	O
ACL2	B-Application
are	O
written	O
in	O
Common	B-Language
Lisp	I-Language
.	O
</s>
<s>
ACL2	B-Application
is	O
free	B-License
and	I-License
open-source	I-License
software	I-License
.	O
</s>
<s>
The	O
ACL2	B-Application
programming	O
language	O
is	O
an	O
applicative	B-Application
(	O
side-effect	O
free	O
)	O
variant	O
of	O
Common	B-Language
Lisp	I-Language
.	O
</s>
<s>
ACL2	B-Application
is	O
untyped	O
.	O
</s>
<s>
All	O
ACL2	B-Application
functions	O
are	O
total	B-Algorithm
—	O
that	O
is	O
,	O
every	O
function	O
maps	O
each	O
object	O
in	O
the	O
ACL2	B-Application
universe	O
to	O
another	O
object	O
in	O
its	O
universe	O
.	O
</s>
<s>
ACL2	B-Application
's	O
base	O
theory	O
axiomatizes	O
the	O
semantics	B-Application
of	O
its	O
programming	O
language	O
and	O
its	O
built-in	O
functions	O
.	O
</s>
<s>
The	O
core	O
of	O
ACL2	B-Application
's	O
theorem	O
prover	O
is	O
based	O
on	O
term	O
rewriting	O
,	O
and	O
this	O
core	O
is	O
extensible	O
in	O
that	O
user-discovered	O
theorems	O
can	O
be	O
used	O
as	O
ad	O
hoc	O
proof	O
techniques	O
for	O
subsequent	O
conjectures	O
.	O
</s>
<s>
ACL2	B-Application
is	O
intended	O
to	O
be	O
an	O
"	O
industrial	O
strength	O
"	O
version	O
of	O
the	O
Boyer	B-Application
–	I-Application
Moore	I-Application
theorem	I-Application
prover	I-Application
,	O
NQTHM	B-Application
.	O
</s>
<s>
Toward	O
this	O
goal	O
,	O
ACL2	B-Application
has	O
many	O
features	O
to	O
support	O
clean	O
engineering	O
of	O
interesting	O
mathematical	O
and	O
computational	O
theories	O
.	O
</s>
<s>
ACL2	B-Application
also	O
derives	O
efficiency	O
from	O
being	O
built	O
on	O
Common	B-Language
Lisp	I-Language
;	O
for	O
example	O
,	O
the	O
same	O
specification	O
that	O
is	O
the	O
basis	O
for	O
inductive	O
verification	O
can	O
be	O
compiled	B-Language
and	O
run	O
natively	B-Language
.	O
</s>
<s>
In	O
2005	O
,	O
the	O
authors	O
of	O
the	O
Boyer-Moore	O
family	O
of	O
provers	O
,	O
which	O
includes	O
ACL2	B-Application
,	O
received	O
the	O
ACM	O
Software	O
System	O
Award	O
"	O
for	O
pioneering	O
and	O
engineering	O
a	O
most	O
effective	O
theorem	O
prover	O
(	O
...	O
)	O
as	O
a	O
formal	O
methods	O
tool	O
for	O
verifying	O
safety-critical	O
hardware	O
and	O
software.	O
"	O
</s>
<s>
ACL2	B-Application
has	O
had	O
numerous	O
industrial	O
applications	O
.	O
</s>
<s>
In	O
1995	O
,	O
J	O
Strother	O
Moore	O
,	O
Matt	O
Kaufmann	O
and	O
Tom	O
Lynch	O
used	O
ACL2	B-Application
to	O
prove	O
the	O
correctness	O
of	O
the	O
floating	O
point	O
division	O
operation	O
of	O
the	O
AMD	O
K5	O
microprocessor	O
in	O
the	O
wake	O
of	O
the	O
Pentium	B-Device
FDIV	I-Device
bug	I-Device
.	O
</s>
<s>
The	O
page	O
of	O
the	O
ACL2	B-Application
documentation	O
has	O
a	O
summary	O
of	O
some	O
uses	O
of	O
the	O
system	O
.	O
</s>
<s>
Industrial	O
users	O
of	O
ACL2	B-Application
include	O
AMD	O
,	O
Arm	O
,	O
Centaur	O
Technology	O
,	O
IBM	O
,	O
Intel	O
,	O
Oracle	O
,	O
and	O
Collins	O
Aerospace	O
.	O
</s>
