ABI is an abbreviation for Application Binary Interface. Every processor’s instruction set has an ABI. This allows the developer to write code in the correct format that the processor is designed to accept. The x86-64 ABI document can be found at the following links:
- 2020 Update: The latest x86-64 ABI can be found here.
- The x86-64 ABI document can be found at x86-64.org. 2020 Update: potential dead link.
- The x86 and generic ABI documents can be found at SCO’s developer page.
- The C++ API can be found at Code Sourcery’s website.
GNU/Linux and many other flavors of Unix use the Executable and Linking Format (ELF)) for executables and shared libraries. The current draft is available at SCO’s website.