This is a project to develop a working an x86 assembler and linker from as small a binary seed as possible. We start with a minimal program capable of generating itself from its source and gradually develop higher level tools and abstractions.
This programs produced in this project are 32-bit ELF executables which run on a Linux kernel running on an Intel x86 processor. They run fine on modern 64-bit systems.
The starting point of the experiment is a tiny program for packing hexadecimal octets into binary.
This stage adds a tool to wrap a text section into a minimal ELF executable, as well as further developing the unhex program to support labels, and references to earlier labels.
This stage introduces a light-weight assembler, written in machine code without forward jumps. It generates a text section that can be wrapped with the stage 1 elfify program to produce an executable.
The assembler is rewritten in assembler language and is joined by a linker, which together allow for separate compilation units.
Various command line utilites are provided in assembly.
The code in stages 0-3 is copyright (C) Richard Smith, and is licensed for use under version 3 or later of the GNU General Public License. The documentation contained in the README.txt files in each stage is licensed under the Creative Commons BY-NC-SA licence, version 4.
The code in stage 4 is derived from the asmutils project and is copyright (C) Konstantin Boldyshev et al. It is licensed under the GNU General Public License version 2 ONLY.
The GPLv2 and the GPLv3 are INCOMPATIBLE with one another. These files can be hosted in the same repo because each util is independent and not linked to any incompatible code. But you cannot copy + paste code from any of the stages 0-3 into any file in stage 4, or vice versa. Be mindful of this.