This is a distribution of NASM, the Netwide Assembler. NASM is a
prototype general-purpose x86 assembler. It will currently output
flat-form binary files, a.out, COFF and ELF Unix object files,
Microsoft Win32 and 16-bit DOS object files, OS/2 object files, the
as86 object format, and a home-grown format called RDF.
Also included is NDISASM, a prototype x86 binary-file disassembler
which uses the same instruction table as NASM.
To install NASM on Linux, type `make', and then when it has finished
copy the file `nasm' (and maybe `ndisasm') to a directory on your
search path (maybe /usr/local/bin, or ~/bin if you don't have root
access). You may also want to copy the man page `nasm.1' (and maybe
`ndisasm.1') to somewhere sensible.
To install under DOS, if you don't need to rebuild from the sources,
you can just copy nasm.exe and ndisasm.exe (16-bit DOS executables),
or nasmw.exe and ndisasmw.exe (Win32 console applications - less
likely to run out of memory), to somewhere on your PATH.
To rebuild the DOS sources, various makefiles are provided:
- Makefile.dos, the one I build the standard 16-bit releases from,
designed for a hybrid system using Microsoft C and Borland Make
(don't ask why :-)
- Makefile.vc, for Microsoft Visual C++ compiling to a Win32
command-line application. This is the one I build the standard
Win32 release binaries from.
- Makefile.bor, for Borland C.
- Makefile.bc2, also for Borland C, contributed by Fox Cutter.
Reported to work better than Makefile.bor on some systems.
- Makefile.sc, for Symantec C++, compiling to a 32-bit extended DOS
executable.. Contributed by Mark Junker.
- Makefile.scw, also for Symantec C++, compiling to a Win32 command-
line application. Also contributed by Mark Junker.
- Makefile.wc, for Watcom C, compiling to a 32-bit extended DOS
executable. Contributed by Dominik Behr.
- Makefile.wcw, also for Watcom C, compiling to a Win32 command-
line application. Also contributed by Dominik Behr.
- Makefile.dj, for DJGPP, compiling to a 32-bit extended DOS
executable. Contributed by Dominik Behr.
- Makefile.lcc, for lcc-win32, compiling to a Win32 command line
application. (The lcc-win32 compiler and tools are available from
I can't guarantee that all of those makefiles work, because I don't
have all of those compilers. However, Makefile.dos and Makefile.vc
work on my system, and so do Makefile.bor and Makefile.bc2.
Be careful with Borland C: there have been various conflicting
reports about how reliable the Huge memory model is. If you try to
compile NASM in Large model, you may get DGROUP overflows due to the
vast quantity of data in the instruction tables. I've had reports
from some people that Huge model doesn't work at all (and also
reports from others that it works fine), so if you don't want to try
moving to Huge, you could try adding the option `-dc' to the
compiler command line instead, which causes string literals to be
moved from DGROUP to the code segments and might make Large model
start working. (Either solution works for me.)
Dominik Behr has also contributed the file misc/pmw.bat, which is a
batch file to turn the output from Makefile.wc (NASM.EXE and
NDISASM.EXE) into standalone executables incorporating Tran's
PMODE/W DOS extender, rather than depending on an external extender
Some of the Windows makefiles produce executables called nasmw.exe
and ndisasmw.exe, and some don't. Be prepared for either...
If you're trying to unpack the DOS (.ZIP format) archive under Unix
instead of using the .tar.gz version, you can save some time by
doing `unzip -aL', which will convert the DOS-format text files to
Unix and also convert all names to lower case.
If you want to build a restricted version of NASM containing only
some of the object file formats, you can achieve this by adding
#defines to `outform.h' (see the file itself for documentation), or
equivalently by adding compiler command line options in the
There is a machine description file for the `LCC' retargetable C
compiler (version 3.6), in the directory `lcc', along with
instructions for its use. This means that NASM can now be used as
the code-generator back end for a useful C compiler.
Michael `Wuschel' Tippach has ported his DOS extender `WDOSX' to
enable it to work with the 32-bit binary files NASM can output: the
original extender and his port `WDOSX/N' are available from his web
Matt Mastracci has written a document explaining how to write
assembly language modules in DJGPP programs using NASM: it's on his
web site at http://www.ucalgary.ca/~mmastrac/djgppasm.doc.
The `misc' directory contains `nasm.sl', a NASM editing mode for the
JED programmers' editor (see http://space.mit.edu/~davis/jed.html
for details about JED). The comment at the start of the file gives
instructions on how to install the mode. This directory also
contains a file (`magic') containing lines to add to /etc/magic on
Unix systems to allow the `file' command to recognise RDF files, and
a zip file (`exasm.zip') containing the necessary files for syntax
highlighting in the Aurora DOS editor. (The Aurora files were
contributed by <U993847220@aol.com>; I haven't tested them as I
don't have Aurora.)
The `rdoff' directory contains sources for a linker and loader for
the RDF object file format, to run under Linux, and also
documentation on the internal structure of RDF files.
For information about how you can distribute and use NASM, see the
file Licence. We were tempted to put NASM under the GPL, but decided
that in many ways it was too restrictive for developers.
For information about how to use NASM, see the various forms of
documentation in the `doc' directory: documentation is provided in
HTML, PostScript, plain text, Texinfo, and Windows Help formats. For
information about how to use NDISASM, see `ndisasm.doc'. For
information about the internal structure of NASM, see
`internal.doc'. (In particular, _please_ read `internal.doc' before
writing any code for us...)
The NASM web page is at http://www.cryogen.com/Nasm/
Bug reports (and patches if you can) should be sent to
<firstname.lastname@example.org> or <email@example.com>.