8. 32-bit x86 Assembly (IA32)
In this chapter, we cover the Intel Architecture 32-bit (IA32) instruction set architecture. Recall that an instruction set architecture (or ISA) defines the set of instructions and binary encodings of a machine-level program. To run the examples in this chapter, you will need access to a machine with an x86 processor or a compiler that can create 32-bit executables. The term "x86" is often used synonymously with the IA32 architecture. The x86, and its 64-bit variant x86-64, are ubiquitous in modern computers.
Very few modern machines have 32-bit processors; most Intel and AMD systems produced since 2007 have 64-bit
processors. To check what type of processor you have, use the uname -p command:
$ uname -p i686
If typing uname -p returns either i686 or i386, your system has a 32-bit processor. However, if the uname -p
command returns x86_64, your system has a newer 64-bit processor. Please note that since x86-64 is an extension of
the older IA32 ISA, virtually all 64-bit systems contain a 32-bit subsystem that allows the execution of 32-bit executables.
If you have a 64-bit Linux system, additional packages are sometimes required to allow users to create 32-bit executables, like we will be doing in this chapter. For example, on an Ubuntu machine you will need to install 32-bit development libraries and additional packages to augment GCC with cross-compiling features:
sudo apt-get install libc6-dev-i386 gcc-multilib