ACL2 Version 7.4
Copyright (C) 2017, Regents of the University of Texas
ACL2 is licensed under the terms of the LICENSE file distributed with ACL2. See also the documentation topic, COPYRIGHT.
Obtaining Allegro Common Lisp
The website for Allegro Common Lisp, a commercial implementation, is
You may be able to obtain a trial version there.
Obtaining CCL (OpenMCL)
Clozure Common Lisp (Clozure CL, or CCL) was formerly known as OpenMCL. Quoting from the Clozure Common Lisp web page (July, 2014): ``Some distinguishing features of the implementation include fast compilation speed, native threads, a precise, generational, compacting garbage collector, and a convenient foreign-function interface.''
Here is an easy way to obtain and build the latest version (generally
recommended) for Linux (or another OS; see below) running on an x86 or
x86-64. First stand in any directory, though you might want to stand
in a fresh directory. Then execute the following shell command to create
ccl subdirectory, but substituting
linuxx86, if appropriate, any of
darwinx86 (which we use for modern Macs),
svn co http://svn.clozure.com/publicsvn/openmcl/trunk/linuxx86/cclNote: if however you insist on using the latest release, you can obtain that instead, for example as follows (but replace "1.9" by the latest version, for example as described at
http://ccl.clozure.com/download.html, and replace
linuxx86if appropriate as described above).
svn co http://svn.clozure.com/publicsvn/openmcl/release/1.9/linuxx86/cclNext rebuild the executable by issuing the following commands, but replace "
./lx86cl64" by a suitable executable; e.g., for 64-bit Darwin (on Mac OS) use "
cd ccl ./lx86cl64 (rebuild-ccl :full t) (quit) ./lx86cl64 (rebuild-ccl :full t) (quit)
Now your CCL executable is up to date. Next, create a suitable
script, say as follows, where
DIR is the full pathname
for the directory above the new
#!/bin/sh tmp=`uname -a | fgrep x86_64` export CCL_DEFAULT_DIRECTORY=DIR/ccl # Start up 64-bit or 32-bit lisp, respectively: if [ "$tmp" != "" ] ; then \ DIR/ccl/scripts/ccl64 $* ; \ else \ DIR/ccl/scripts/ccl $* ; \ fi
my-scriptthen on linux you might want to execute the following shell command.
chmod +x my-scriptYour script (invoked with a suitable pathname, or just the filename if the directory is on your path) will now start the updated CCL lisp image.
More details if you want or need them:
Step 3 in
has more details on building from source.
Alternatively, you can download a gzipped tar
file; see the main
Clozure CL page. (Note: Subversion and gzipped tar
files are great, but not so much a CCL disk image (
file), as we have had a report of the extracted CCL opening its own
window when you start it up.) If you don't want to write your own
script (as suggested above) then after obtaining CCL, you may wish to
ccl/scripts/ccl or file
ccl/scripts/ccl64, depending on whether you want to
use a 32-bit or 64-bit version (respectively).
CLISP is a non-commercial Common Lisp implementation, available from
We do not recommend CLISP as a platform for ACL2, for the following
Obtaining CMU Common Lisp
CMU Common Lisp (sometimes called CMUCL) is a non-commercial Common Lisp
implementation, available from
You might be able to download a binary Debian package for ACL2. Thanks to Camm Maguire for maintaining this package. Note however that it may take some time after each ACL2 release for this binary Debian package to be updated for that release.
Otherwise, it should be easy to obtain and build GCL yourself. Note
that ACL2 requires GCL version 2.6.12 or later, which can be fetched
as a tarball from the main
GNU website for GCL or perhaps
ACL2 also requires an ANSI Common Lisp executable;
after unpacking the archive, an ANSI GCL can be built as follows.
cd gcl && ./configure --enable-ansi && make
LispWorks is a commercial Common Lisp implementation. You can download
a free, restricted, version
You may ask the vendor for an evaluation license for the full product
if you are considering purchasing a license.
SBCL (Steel Bank Common Lisp) is a non-commercial Common Lisp
implementation, available from
Building ACL2 may initially fail with SBCL because of insufficient heap
memory. Harsh Raju Chamarthi points out that a fix is to run SBCL
with an increased heap size limit. As of 2014 we find that the
--dynamic-space-size 2000 following works well
on 64-bit linux, for example using a script like the following for
#!/bin/sh <sbcl-dir-path>/src/runtime/sbcl --core <sbcl-dir-path>/output/sbcl.core --dynamic-space-size 2000 "$@"
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