Open Watcom Assembler
This article possibly contains original research. (September 2016)
|Original author(s)||Open Watcom Assembler|
|Operating system||DOS for x86-based PCs, Microsoft Windows, Linux for x86-based PCs, OS/2 for x86-based PCs, FreeBSD for x86-based PCs.|
Open Watcom Assembler or WASM is an x86 assembler produced by Watcom, based on the Watcom Assembler found in Watcom C/C++ compiler and Watcom FORTRAN 77. Further development is being done on the 32- and 64-bit JWASM project,. which more closely matches the syntax of Microsoft's assembler.
- Native support for output formats Intel OMF output formats
- Supports Intel x86 (Pentium MMX, Pentium III-4, 3DNow!, SSE and SSE2) instruction sets.
- Supports Microsoft macro assembler (MASM) 5 and 6 syntax (incomplete).
There is an associated Watcom disassembler, wdis. The assembler does not have listing facilities; instead the use of wdis for generating listings is recommended. 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.
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
- 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 of JWASM in January 2014 with version 2.12pre, but others on the Masm32 forum 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. New features include:
- MMX: MOVQ and added in 2.13, to supplement MOVD.
- AVX2: VGATHERDPD, VGATHERQPD, VGATHERDPS, VGATHERQPS, VPGATHERDD, VPGATHERQD, VPGATHERDQ, VPGATHERQQ, VEX-encoded general purpose instructions added in 2.13. Remaining instructions added in 2.16.
- AVX-512: VCMPxxPD, VCMPxxPS, VCMPxxSD, VCMPxxPD, VCMPxxSS, AVX-512F set, EVEX-encoded instructions added in 2.13; VMOVQ added 2.13, to supplement MOVD. Remaining instructions added in 2.16.
- Registers: RIP, ZMM registers added in 2.13.
- OO language extension added in 2.25.
UASM 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, and was finalized at the end of discussion thread at Reply #33. No known features are added in HASM's release cycle.
- Instruction sets: RDPID added in 2.38.
- AVX-512: VAESDEC added in 2.38
- Data transfer: MOVBE added in 2.47. MOVABS added in 2.48.
- Intel ADX: ADCX, ADOX added in 2.38
- Intel MPX: Support of BND prefix added in 2.34. BND prefix removed from JCXZ instruction group in 2.40.
- CLMUL instruction set: Added in 2.46.8, including pseudo-op forms of CLMUL.
- Hashing: SHA instruction set added in 2.46.8.
- Supervisor Mode Access Prevention: CLAC added in 2.38.
- Persistent Memory Extensions: CLFLUSHOPT added in 2.38.
- Addressing modes: 64bit absolute immediate (2.37)
- Identified types
- Record types: fully supports registers and up to 32bit record fields in 2.41.
- Support for 128bit: Added in 2.42, inline declaration with the type added in 2.43.1 / .2.
- Support of typedef chain on return types added in 2.46.8.
- m512 built-in types added in 2.47.
- Console colour coding: Added for Windows, OSX and Linux in 2.43.1 / .2.
- Function calling: C-style function calling added in 2.46.
- Randall Hyde. "WASM: The Open Watcom Assembler". Archived from the original on 2012-03-02. Retrieved 2017-09-11.CS1 maint: bot: original URL status unknown (link)
- Leiterman, James (2005). "MASM vs. NASM vs. TASM vs. WASM". 32/64-bit 80x86 assembly language architecture. Wordware Publishing, Inc. p. 481. ISBN 978-1-59822-002-5. Retrieved 2010-02-01.
- Leiterman p482 on Google Books
- JWASM, a 32/64 bit assembler based on WASM with syntax similar to MASM. Archived 10 October 2014
- Fog, Agner (2009), Optimizing subroutines in assembly language (PDF) (2009-09-26 ed.), p. 13
- Open Watcom website: Assembler Archived 2006-07-15 at the Wayback Machine
- 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."
- Open Watcom website: Disassembler Archived 2006-07-15 at the Wayback Machine
- The 1996 "WALK32 consists of the following main components:
- A full-featured PE (Portable Executable) file linker called W32Link.
- A main include file, containing Win32 constant, type, and structure definitions.
- Another include file, containing the application and DLL startup source code.
- Segment and PE section management macros.
- Macros related to Unicode support.
- Several demo applications and DLL’s.
- A collection of programming utilities for various purposes." walk32.doc in walk32_1.zip
- UASM Assembler Development
- HJWasm Releases
- A New Name? (thread page 1)
- A New Name? (thread page 3)
- UASM (2.33)
- UASM 2.33 Release
- UASM ChangeLog