The Netwide Assembler, NASM, is an 80x86 assembler designed for
portability and modularity. It supports a range of object file formats,
including Linux and NetBSD/FreeBSDa.out, ELF,
COFF, Microsoft 16-bit
OBJ and Win32. It will
also output plain binary files. Its syntax is designed to be simple and
easy to understand, similar to Intel's but less complex. It supports
Pentium, P6,
MMX, 3DNow!,
SSE and SSE2 opcodes,
and has macro capability.
The Netwide Assembler grew out of an idea on
comp.lang.asm.x86 (or possibly
alt.lang.asm - I forget which), which was
essentially that there didn't seem to be a good free x86-series
assembler around, and that maybe someone ought to write one.
a86 is good, but not free, and in particular
you don't get any 32-bit capability until you pay. It's DOS only, too.
gas is free, and ports over DOS and Unix, but
it's not very good, since it's designed to be a back end to
gcc, which always feeds it correct code. So its
error checking is minimal. Also, its syntax is horrible, from the point of
view of anyone trying to actually write anything in it. Plus you
can't write 16-bit code in it (properly).
as86 is Minix- and Linux-specific, and (my
version at least) doesn't seem to have much (or any) documentation.
MASM isn't very good, and it's (was)
expensive, and it runs only under DOS.
TASM is better, but still strives for MASM
compatibility, which means millions of directives and tons of red tape. And
its syntax is essentially MASM's, with the contradictions and quirks that
entails (although it sorts out some of those by means of Ideal mode). It's
expensive too. And it's DOS-only.
So here, for your coding pleasure, is NASM. At present it's still in
prototype stage - we don't promise that it can outperform any of these
assemblers. But please, please send us bug reports, fixes, helpful
information, and anything else you can get your hands on (and thanks to the
many people who've done this already! You all know who you are), and we'll
improve it out of all recognition. Again.
Please see the file COPYING, supplied as part
of any NASM distribution archive, for the licence conditions under which
you may use NASM. NASM is now under the so-called GNU Lesser General Public
License, LGPL.
The current version of NASM (since about 0.98.08) are maintained by a
team of developers, accessible through the
nasm-devel mailing list (see below for the link).
If you want to report a bug, please read
section 10.2 first.
If you want information about NASM beta releases, and the current
development status, please subscribe to the
nasm-devel email list by registering at
http://sourceforge.net/projects/nasm.
Once you've obtained the DOS archive for NASM,
nasmXXX.zip (where XXX
denotes the version number of NASM contained in the archive), unpack it
into its own directory (for example c:\nasm).
The archive will contain four executable files: the NASM executable
files nasm.exe and
nasmw.exe, and the NDISASM executable files
ndisasm.exe and
ndisasmw.exe. In each case, the file whose name
ends in w is a Win32
executable, designed to run under Windows 95 or
Windows NT Intel, and the other one is a 16-bit
DOS executable.
The only file NASM needs to run is its own executable, so copy (at
least) one of nasm.exe and
nasmw.exe to a directory on your PATH, or
alternatively edit autoexec.bat to add the
nasm directory to your
PATH. (If you're only installing the
Win32 version, you may wish to rename it to
nasm.exe.)
That's it - NASM is installed. You don't need the nasm directory to be
present to run NASM (unless you've added it to your
PATH), so you can delete it if you need to save
space; however, you may want to keep the documentation or test programs.
If you've downloaded the DOS source archive,
nasmXXXs.zip, the nasm
directory will also contain the full NASM source code, and a selection of
Makefiles you can (hopefully) use to rebuild your copy of NASM from
scratch.
Note that the source files insnsa.c,
insnsd.c, insnsi.h and
insnsn.c are automatically generated from the
master instruction table insns.dat by a Perl
script; the file macros.c is generated from
standard.mac by another Perl script. Although the
NASM source distribution includes these generated files, you will need to
rebuild them (and hence, will need a Perl interpreter) if you change
insns.dat, standard.mac or the documentation. It is possible future source
distributions may not include these files at all. Ports of Perl for a
variety of platforms, including DOS and Windows, are available from
www.cpan.org.
Once you've obtained the Unix source archive for NASM,
nasm-X.XX.tar.gz (where
X.XX denotes the version number of NASM contained
in the archive), unpack it into a directory such as
/usr/local/src. The archive, when unpacked, will
create its own subdirectory nasm-X.XX.
NASM is an auto-configuring package: once you've unpacked it,
cd to the directory it's been unpacked into and
type ./configure. This shell script will find the
best C compiler to use for building NASM and set up Makefiles accordingly.
Once NASM has auto-configured, you can type
make to build the nasm
and ndisasm binaries, and then
make install to install them in
/usr/local/bin and install the man pages
nasm.1 and ndisasm.1 in
/usr/local/man/man1. Alternatively, you can give
options such as --prefix to the configure script
(see the file INSTALL for more details), or
install the programs yourself.
NASM also comes with a set of utilities for handling the
RDOFF custom object-file format, which are in the
rdoff subdirectory of the NASM archive. You can
build these with make rdf and install them with
make rdf_install, if you want them.
If NASM fails to auto-configure, you may still be able to make it
compile by using the fall-back Unix makefile
Makefile.unx. Copy or rename that file to
Makefile and try typing
make. There is also a Makefile.unx file in the
rdoff subdirectory.