1.6. Supported Object Formats
Yasm supports the following object formats. More details can be found in Part IV.
- The “bin” object format
produces a flat-format, non-relocatable binary file. It is appropriate for producing DOS
.COM executables or things like boot blocks. It supports only 3 sections and those
sections are written in a predefined order to the output file.
- The COFF object format is an older relocatable object format used on older Unix and
compatible systems, and also (more recently) on the DJGPP development system for
- The “dbg” object format is
not a “real” object format; the
output file it creates simply describes the sequence of calls made to it by Yasm and the
final object and symbol table information in a human-readable text format (that in a
normal object format would get processed into that object format’s particular binary
representation). This object format is not intended for real use, but rather for
debugging Yasm’s internals.
- The ELF object format really comes in three flavors: “elf32” (for 32-bit targets), “elf64” (for 64-bit targets), and
“elfx32” (for x32 targets). ELF
is a standard object format in common use on modern Unix and compatible systems (e.g.
Linux, FreeBSD). ELF has complex support for relocatable and shared objects.
- The Mach-O object format really comes in two flavors: “macho32” (for 32-bit targets) and
“macho64” (for 64-bit targets).
Mach-O is used as the object format on MacOS X. As Yasm currently only supports x86 and
AMD64 instruction sets, it can only generate Mach-O objects for Intel-based Macs.
- The RDOFF2 object format is a simple multi-section format originally designed for
NASM. It supports segment references but not WRT references. It was designed primarily
for simplicity and has minimalistic headers for ease of loading and linking. A complete
toolchain (linker, librarian, and loader) is distributed with NASM.
- The Win32 object format produces object files compatible with Microsoft compilers
(such as Visual Studio) that target the 32-bit x86 Windows platform. The object format
itself is an extended version of COFF.
- The Win64 object format produces object files compatible with Microsoft compilers
that target the 64-bit “x64”
Windows platform. This format is very similar to the win32 object format, but produces
- The XDF object format is essentially a simplified version of COFF. It’s a
multi-section relocatable format that supports 64-bit physical and virtual