Free Assemblers, Linkers and Object Module Librarians

Assembly language tools: assemblers, cross-assemblers, linkers, librarians

Free Assemblers, Linkers and Object Module Librarians

Looking for an assembler or linker or librarian to write that high speed routine or application? This page lists assemblers, cross-assemblers, linkers, and librarians, where available, for a wide variety of operating systems and processors.

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Free Assemblers, Linkers and Object Module Librarians


YASM, a rewrite of the NASM assember (also listed on this page), supports the Intel x86 and AMD64 instruction sets. At the time I write this, it is "nearly feature-complete" in its support of the NASM and GAS (the GNU assembler) syntax, along with basic support of the TASM (the old Turbo assembler) syntax. It can produce a variety of output formats, including the Win32, Win64/AMD64, ELF32, ELF64, 32 and 64-bit Mach-O, COFF and binary object files, and generate source-debugging information in the STABS, DWARF 2 and CodeView 8 formats. It is open source and released under a BSD licence. Binaries/executables are available for Windows and DOS.

Nasm - The Netwide Assembler

This is a free macro assembler that assembles Intel x86 assembly code. It generates a wide range of object file formats, including a.out, ELF, COFF, Mach-0, Microsoft OBJ, etc. It can also output plain binary files. It supports Pentium, P6, MMX, 3DNow!, SSE, and SSE2 opcodes. It runs on MSDOS, Win32, Linux and other platforms. It is released under the simplified (2-clause) BSD licence ("license" if you use a different variant of English).

FASM: Flat Assembler

Flat Assembler is an Intel x86 macro assembler for MSDOS, Win32, Linux systems that accepts 16 bit and 32 bit 80x86/Pentium code, MMX, SSE, SSE2 instructions, and macros,. According to the website, it also has support for "code optimization", and can generate binary files, MZ and PE executables.


VASM is an assembler for a wide variety of CPUs, such as the M680x0 family (including M6888x, M68851, CPU32), ColdFire family (all models of V2, V3, V4, V4e), the PowerPC family (POWER, 40x, 440, 460, 6xx, 7xx, 7xxx, 860, Book-E, e300, e500), the Z80 family (8080, Z80, GBZ80, 64180, RCM2/3/4k), the 6502 family, Jaguar RISC (GPU and DSP instruction sets), ARM (ARMv1 to ARMv4), the x86 family (up to the 32-bit processors; using MIT syntax), C16x/ST10, the 6800 family (6800, 6801, 6803, 68HC11), QNICE, TR3200, and Raspberry Pi VideoCore IV. The assembler supports macros, include directives, repetitions, conditional assembly, local symbols, optimizations (eg, choosing the shortest branch instruction or addressing mode), relaxations (eg, changing a branch instruction to an absolute jump where needed), etc. It can create linkable as well as absolute code, in a variety of output formats (depending on the target CPU), as well as debugging output.

NBASM, NewBasic Assembler

This x86 assembler is near MASM 5.1x compatible, and is designed for newcomers to assembly language. It generates MSDOS executables.

High Level Assembly Language (HLA)

This tool converts your code, written in HLA into 80x86 assembly language, which you can then assemble with masm or fasm. It apparently uses high level constructs from the high level programming languages like C/C++, and Pascal/Delphi.


Devore Software has released their WarpLink linker for MSDOS (previously a commercial product) into the public domain (yes - public domain!) and the linker and documentation can be freely downloaded, used, sold, as you please. WarpLink can create MSDOS software with overlays as well. The program is no longer maintained. Update: the web page that previously described this linker is no longer available. However, the files are available from the link above. I have not actually verified this by downloading and opening them, but judging from the filenames alone, I think the relevant files are those that begin with wl, ie,,, and


This free linker has the ability to link a wide variety of object code modules, from the OMF format generated by Borland's compilers to the COFF format used by Microsoft's compilers. It is able to generate MSDOS COM and EXE files as well as Win32 PE EXE and DLL files. Resource files are also supported for the PE output files. It comes with source code, but appears to be no longer maintained.

CodeX Assembler

The CodeX assembler is an Intel assembler that supports not only the Pentium instruction sets (including Pentium 4) but also the AMD 3D Now! instruction set. It can generate flat model binaries (16 and 32 bits), DOS executables, Windows applications and Windows DLLs.


A DOS linker that can link OBJ files to produce EXE or COM files for the MSDOS system. It is supposed to be typically ten times faster than MS LINK and can handle USE32 segments that are larger than 64k. According to the web page, the author hopes to implement support for generating debugging information for CodeView and Turbo Debugger. Note: the utility was written by Qualitas Inc for its internal use (remember the 386MAX memory manager?).

Microsoft Macro-Assembler (MASM) 8.0

[Update: this file is no longer available. For the record, it used to be at] Microsoft Macro-Assembler, or MASM, is now available for non-commercial use. The download page says that you will need the Visual C++ 2005 Express Edition to use it. I'm not sure if the later editions of the Visual Studio, as mentioned on the Free C/C++ Compilers page, will work with it. This is a Windows program.

V810 Assembler

[Update: this assembler seems to be gone.] This is a V810 assembler written using Java and ANTLR, for Virtual Boy programming. You have to scroll down the page to find the assembler.

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