The Yasm Modular Assembler Project

Key Current User-Visible Features ¶

• Nearly feature-complete lexing and parsing of (preprocessed) NASM syntax.
• Limited lexing and parsing of GAS (GNU assembler) syntax? (in progress).
• AMD64 support (enabled using "BITS 64" and "-m amd64" option)
• 64-bit (and larger) integer constants allowed (including math operations).
• Internationalization support via GNU gettext.
• A simple 2-pass optimizer (it's a bit better than the NASM one).
• The "real" NASM preprocessor (imported from NASM's source tree).
• Binary object file? output (NASM style).
• COFF object file? output, for use with DJGPP.
• Win32 object file? output (including Win64/AMD64 support).
• STABS debug format.
• ELF32 and ELF64 object file output. No debugging information included at this point.
• Portability; currently compilable on:
  • UNIX and compatibles (FreeBSD and Linux tested, GNU configure based autoconfiguration)
  • DOS (using DJGPP)
  • Windows (using Visual C++‎ or CygWin).

Key Internal Features ¶

• A NASM syntax parser written in yacc. This simplifies the source code and increases performance: yacc-generated parsers are almost always faster than hand-written ones. Also, yacc (and its GNU implementation, bison) is an extremely well-tested and well-documented tool.
• Architecture-specific instruction parsers hand-written for simplicity and size, as well as to make it easy to add additional architectures while retaining the same front-end syntax. The blend of yacc for syntax and a hand-written parser for instructions strikes a great balance between the strengths and weaknesses of each approach.
• A NASM syntax lexer written in re2c. A highly efficient scanner generator (almost always faster than lex/flex), it's also very embeddable due to its code generation methodology, allowing a number of re2c scanners to be used in various places in yasm without any worries about naming conflicts.
• A GAS syntax? lexer and parser written in re2c and yacc, respectively.
• Many of the modular interfaces at least superficially finished. This is still an area that needs a lot of work.
• A small set of portable equivalants of useful functions that are standard on some systems (detected via configure), such as the queue(3) set of functions, strdup, strcasecmp, and mergesort.
• A decent (and growing) set of assembler test input files to test the entire assembler as well as specific modules

http://www.tortall.net/projects/yasm/