Target Audience

Welcome to the 0.7.2 release of the Yasm Modular Assembler. Its target audience includes people who want to:

use a mature NASM-syntax x86 and AMD64 assembler that can target Win32, Win64, MacOS X, and Unix derivatives;
use a GAS-syntax assembler other than GAS;
have assembly source-level debugging using either DWARF2 or CodeView 8.0 (2005);
have a free software assembler that supports Win32/Win64 structured exception handling (SEH) and ELF32/ELF64 thread local storage (TLS);
target the new AMD SSE5 or Intel AVX instruction sets;
keep track of Yasm’s progress in terms of stability and feature set;
contribute to Yasm development from a new release.

Download Yasm 0.7.2

A number of download formats are available. For Windows and DOS users, we recommend downloading the prebuilt binaries. The source tarball contains all sources needed to build Yasm on UNIX-compatible systems, Windows, and DOS.

Source .tar.gz
Win32 .exe (for “normal” (Visual Studio or similar) use on 32-bit Windows)
Win64 .exe (for “normal” (Visual Studio or similar) use on 64-bit Windows)
Win32 .exe (for CygWin use)
DOS .exe (for use on pure DOS or for use with DJGPP)

Features

Changes from 0.7.1 to 0.7.2:

Add PIC support to 64-bit Mach-O (#141).
Add –prefix and –suffix options for naming globals (#132).
Make rel foo wrt ..gotpc generate GOTPCREL in elf64 (alias for rel foo wrt ..gotpcrel).
Add support for newly specified AVX/AES instructions not in original spec.
Remove invalid 256-bit form of VPBLENDVB.
Optimize non-strict push with 66h override to byte size if possible.
Fix address printing in bin map file.
Fix GAS syntax handling of no section flags (#148).
Name the absolute symbol in coff/win32/win64 output (#153).
Miscellaneous other fixes.

Changes from 0.7.0 to 0.7.1:

AVX instruction bugfixes (0.7.0 errata)
Build fixes (crashes on some machines)
Minor CPU flags fixes

Changes from 0.6.2 to 0.7.0:

Intel Advanced Vector Extensions (AVX) instruction support.
Multi-section binary support (see #71, #99, r2010).
Add support for ELF32 and ELF64 TLS (thread local storage) relocations.
Allow use of 0X in addition to 0x to prefix hex constants (#127).
Allow underscores in hex, binary, and octal constants (e.g. 0111_1111b).
Fix memory sizes on SSE/SSE2 instructions (#119).
Allow standalone prefixes (#122).
Simplify new varieties of sym-sym values (#124).
Support SAFESEH directive for win32 SEH handlers (#130).
Enable sym@FOO constructs in GAS parser.
SSE5 condition code support.
Other bugfixes.

Features also include:

Object and debugging format support:

Full support for ELF, including support for both AMD64 and 32-bit x86 static and shared objects and thread local storage.
Support for Mach-O object format used in MacOS X, including both the 32-bit (x86) and 64-bit (AMD64) versions (contributed by Henryk Richter).
Full support for COFF (DJGPP) and Win32 (PE32) and Win64 (PE32+) object formats.
Support for structured exception handling on Win64 and Win32.
Support for RDOFF2 (.rdf) object format.
XDF object format (64-bit basic format, similar in spirit to NASM’s RDF).
Multi-section binary support (compatible but slightly more advanced than NASM’s).
STABS, DWARF2, and CodeView 8 debugging formats (enable with “-g …”).

Assembler syntax support:

Full NASM-compatible parser, including the “real” NASM preprocessor (imported from NASM tree).
GAS parser good enough to take GCC output for both AMD64 and 32-bit x86 (including DWARF2 debug information).

Architecture support:

Support for AMD64 instruction set, registers, and addressing modes. This is enabled in one of three ways: using the [BITS 64] directive, using a 64-bit object format such as win64 or elf64, or setting the machine to “amd64”. Only the last two will actually generate a 64-bit object file.
Full support for AMD64 RIP-relative addressing; the two forms supported are [rip+val] (direct index) and [sym wrt rip] (relocated relative).

Other features:

Fast and efficient “virtual multi-pass” optimizer that automatically generates much smaller code for jumps and immediates.
Full warnings for integer overflow.
NASM-like list format.
Most code licensed under 2-clause BSD license, although some portions are still LGPL-licensed (NASM preprocessor module).
Support for the -I option to specify include directories, with a search pattern essentially identical to most C compilers.
Support for CALL/JMP FAR, including proper handling of location EQU seg:off; jmp location.
Man pages: yasm(1), yasm_objfmts(7), yasm_dbgfmts(7), and yasm_arch(7).

Important Differences from NASM

A number of command line options are different. Run “yasm –help” for a quick command line option summary, or read the full yasm(1) manpage for detailed descriptions of all command line options.
Include files with relative paths are not searched in the same way. Yasm’s search behavior is essentially that of most C compilers.

Known Issues

As Yasm is still under development, there are some caveats and features that do not yet work or are not yet fully functional. See the Tickets area of Yasm’s website for a list of active issues.

Compiling Yasm from source

On UNIX-compatible operating systems, Yasm builds using the standard “./configure; make; make install” commands. GNU make is not required. While Yasm development requires a larger toolchain (see the HACKING file), building Yasm should not require more than just a C compiler.

For Windows and DOS systems, we recommend simply downloading the prebuilt executables. However, for those that want to build YASM directly using DJGPP, CygWin, or Visual C++, Makefiles and all required specialized files are provided in the Mkfiles/ directory of the distribution tarball.

Running Yasm

Version Information:

yasm --version

Command Line Option Help:

yasm --help

Assemble test.asm to Win32 object file test.obj with CodeView 8.0 (VS2005) source debug info:

yasm -f win32 -g cv8 test.asm

Assemble test2.asm to Win64 object file test.obj with CodeView 8.0 source debug info:

yasm -f win64 -g cv8 test2.asm

Assemble test3.asm to AMD64 ELF object file test3.o with DWARF2 debugging information:

yasm -f elf64 -g dwarf2 test3.asm

Alternative to above:

yasm -f elf -m amd64 -g dwarf2 test3.asm

Assemble test4.s (GAS syntax file) to 32-bit x86 ELF object file testo.o with DWARF2 debugging information:

yasm -p gas -f elf32 -g dwarf2 -o testo.o test4.s

Yasm 0.7.2 Release Notes