1. About JWasm
JWasm is a free MASM-compatible assembler with these features:
native support for output formats Intel OMF, MS Coff (32/64-bit), Elf (32/64-bit), Binary, Windows PE (32/64-bit) and DOS MZ.
precompiled JWasm binaries are available for DOS, Windows and Linux. For OS/2 and FreeBSD, makefiles are supplied.
Instructions up to AVX are supported.
JWasm is written in C. The source is portable and has successfully been tested with Open Watcom, MS VC, GCC and more.
As far as programming for MS Windows is concerned, JWasm can be used with both WinInc (32/64-bit) and Masm32 (32-bit). Since v2.01, it will also work with Sven B. Schreiber's ancient WALK32.
C header files can be converted to include files for JWasm with h2incX.
JWasm's source code is released under the Sybase Open Watcom Public License, which allows free commercial and non-commercial use.
There's a bunch of source samples available - they are supplied with the precompiled binary packages.
JWasm started as a fork of Open Watcom's Wasm in March 2008. Today, the part of Wasm source lines still contained in JWasm is approximately 20%.
Additional information:
JWasm's Readme.
Manual, describes the differences between JWasm and Masm. For a good description of Masm's syntax and features, see Art of Assembly Language Programming.
Table of pros and cons of JWasm compared to other Masm-style assemblers.
Symbolic Debugging of assembly code with
MS WinDbg, 32- and 64-bit Windows.
Pelle Orinius' POIDE, 32- and 64-bit Windows.
Open Watcom's WDW, 16- and 32-bit Windows, 16-bit DOS.
Open Watcom's WD, 16- and 32-bit DOS.
MS CodeView, 16-bit DOS.
How to use JWasm with MS Visual Studio 2005/2008/2010/2012
2. User Feedback
JWasm uses SourceForge for user feedback:
Bug reports
Feature requests
Open Discussion, Help
3. Downloads
Binary Windows
Binary Linux
Binary DOS
Source
JWasm v2.11a 16.11.2013 JWasm211bw.zip JWasm211bl.zip JWasm211bd.zip JWasm211as.zip change log
JWasm v2.12 pre 19.12.2013 JWasm212bw.zip JWasm212bd.zip change log
List of all JWasm versions available for download
Helper tools
WRC - OW resource compiler v1.9 05/2010 Win32 wrc.zip (binary)
WDW - modified OW Windows debugger v1.9,
may debug Win32, Win16 and DOS apps locally 01/2013 Win32 wdw.zip (binary)
WD - OW DOS debugger v1.9 05/2010 DOS wd.zip (binary)
PE - PE, COFF, AR dumper;
may dump CV4-CV8 debug info in COFF files 03/15/2013 Win32, DOS pe.zip (binary)
DumpOmf - OMF dumper 10/27/2013 Win32 DumpOmf16.zip (binary & source)
Agner Fog's ObjConv v2.09 -
Object format converter + Disassembler 08/2009 DOS objconv.zip (binary)
MS OMF Linker v5.60 12/1994 Win32, DOS lnk563.exe (MS FTP host) lnk563.exe (MS HTTP)
MS NMake v1.5
