There is an associated Watcom disassembler, wdis. The assembler does not have listing facilities; instead the use of wdis for generating listings is recommended.[7] wdis can read OMF, COFF and ELF object files and PE and ELF executables. It supports 16-bit and 32-bit x86 instruction set including MMX, 3DNow!, SSE, SSE2, and SSE3. Support for PowerPC, Alpha AXP, MIPS, and SPARC V8 instruction sets is also built in.[8]
JWasm is a fork of Wasm originated by Japheth with following features:
Native support for output formats Intel OMF (16/32-bit), MS Coff (32-bit and 64-bit), Elf (32-bit 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.
Supports Intel x86 (8086, 80186, 80286, 80386, 80486, Pentium, Pentium Pro), x86-64 instruction sets with SIMD (MMX, 3DNow!, SSE, SSE2, SSE3 and SSSE3, SSE4.1/2 (since Jwasm), AVX (since JWasm 2.06), VMX (Intel VT-x; AMD SVM, the latter though already implemented, currently still inactive) extensions (since JWasm 2.09)).
JWasm is written in C. The source is portable and has successfully been tested with Open Watcom, MS VC, GCC and more.
On Windows, JWasm can be used with both Win32Inc and Masm32. Since v2.01, it will also work with Sven B. Schreiber's SBS WALK32 Win32 Assembly Language Kit[9]
C header files can be converted to include files for JWasm with Japheth's own dedicated h2incX.
JWasm's source code is released under the Sybase Open Watcom Public License, which allows free commercial and non-commercial use.
Fully supports Microsoft macro assembler 6 syntax, all MASM 8 instructions sets.
Japheth ceased development (or rather, was out of contact) of JWASM in January 2014 with version 2.12pre, but others on the Masm32 forum[10] picked up where Japheth left off.
HJWasm, adding the prefix H in reference to Masm32 forum member Habran who started off this second WASM development continuation. Version 2.13pre was originally announced in 2016.[11] New features include:
HASM is a renamed version of HJWASM, starting in version 2.33. The name was used following a MASM Forum discussion thread that originally proposed a replacement name. The name HASM was proposed by forum member habran in Reply #6,[12] and was finalized at the end of discussion thread at Reply #33.[13] No known features are added in HASM's release cycle.
The name was actually used in version 2.33 (dated 2017-05-20) at Terraspace ltd's product page,[14] but it was only announced in version 2.34.[15] Changes to HJWASM includes:[16]
^OpenWatcom: "No listing files are generated [by the assembler]. Producing full listings may be a waste of effort because wdis (the Open Watcom disassembler) does a very good job. However, it could be extremely helpful to produce a dump of the internal symbol table the way MASM does, especially for diagnostic purposes."