JWasm
1. About
JWasm is a free MASM-compatible assembler with these features:- native support for output formats Intel OMF, MS Coff (32- and 64-bit), Elf (32-and 64-bit), Bin and DOS MZ.
- precompiled JWasm binaries are available for DOS, Windows and Linux. For OS/2 and FreeBSD, makefiles are supplied.
- Instructions up to SSE4.2 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 Windows is concerned, JWasm can be used with both Win32Inc and Masm32. 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.
More details.
JWasm is a fork of Open Watcom's Wasm. The version of Wasm which was used for the fork was v1.7a, that's why JWasm version numbering starts with v1.70. Here's a list of the additions and bugfixes which was done during the transition
2. JWasm compared with other MASM-like Assemblers
There are - at least - 4 assemblers available which (partially) understand MASM syntax:- MASM, the original, Microsoft
- TASM, Borland
- POASM, part of PellesC
- WASM, part of Open Watcom. [Wasm is neither Masm v6 nor v5 compatible, but it understands both Masm v5 and v6 syntax partially. Additionally it knows how to encode instructions implemented in newer cpus.]
| JWasm compared with | Advantages | Disadvantages |
|---|---|---|
| MASM | JWasm is free, no artificial license restrictions, can be used to create binaries for any OS. | None. |
| JWasm is open source, forget the annoying MASM bugs ... | ||
| More output formats supported (Bin, ELF). | ||
| optionally very small object modules can be created | ||
| better support for Open Watcom, for example the register-based calling convention | ||
| JWasm is faster than Masm. | ||
| TASM | JWasm is available. TASM isn't legally available. And LZASM, which is sort of a TASM clone, understands IDEAL mode only. | TASM additionally understands IDEAL mode. This was a big advantage compared to MASM v5.1, but compared to MASM v6 syntax there are no benefits anymore. |
| JWasm has full support for STRUCTs and UNIONs. TASM has severe limitations and bugs in this area. | ||
| JWasm supports virtually all MASM v6 features (PROTO, INVOKE, hll directives, ... ), most of which TASM won't understand. | ||
| JWasm supports instructions up to SSE4, TASM is behind. | ||
| POASM | JWasm is open source | None. |
| JWasm additionally supports output in OMF, ELF and binary format | ||
| JWasm supports 16-bit and segmented memory models. POASM understands FLAT only. | ||
| JWasm is compatible with MASM's implementation of macros. POASM isn't. | ||
| POASM lacks the ability to create a listing file. | ||
| WASM | JWasm's macro capabilities are ways better than Wasm's. | Wasm's cmdline is more compatible with Open Watcom tools |
| JWasm fully supports Masm v6 syntax. In Wasm, most of the additions done in Masm v6 are missing. | ||
| Besides OMF, JWasm supports COFF, ELF and binary output formats. | ||
| JWasm supports 64-bit. |
3. Source Samples
4. User Feedback
JWasm uses SourceForge for user feedback:5. Roadmap
Pipeline for next releases:- symbolic debug info for output format ELF.
6. Downloads
| Binary Win32, DOS |
Binary Linux |
Binary DOS 16-bit |
Source | |||
|---|---|---|---|---|---|---|
| JWasm v2.02 | 01/19/2010 | JWasm202b.zip | JWasm202bl.zip | JWasm202br.zip | JWasm202s.zip | change log |
List of all versions available for download
Helper tools
| JWLink (improved OW WLink v1.8) | 09/2009 | binary (Win32) |
| OW WDW - Debugger for NT/XP | 02/2009 | binary (Win32) |
| PE (PE, COFF, AR dumper) | 01/13/2010 | binary & source (Win32, DOS) |
| Agner Fog's ObjConv v2.09 | 08/2009 | binary (DOS) |
| MS OMF Linker v5.60 | 12/1994 | binary (Win32) |
| MS NMake v1.5 | 1994 | binary (Win32) |