o32

o32 is a designation used in different domains, but it is most notably associated with the MIPS architecture as the o32 application binary interface (ABI). The o32 ABI stands for "old 32-bit" and represents a legacy 32-bit ABI used by 32-bit MIPS processors. It is one of several MIPS ABIs, alongside n32 and the 64-bit ABI.

Binaries built for o32 are not compatible with the 64-bit ABIs; they rely on 32-bit pointers and integers and have their own calling convention and register usage. Historically, o32 was widely used on early MIPS Linux and BSD ports, and it remains in use primarily for compatibility with older software and hardware.

In practice, o32 appears in toolchains and build configurations as the ABI directive, for example enabling the compiler flag -mabi=o32. On platforms that support multiple MIPS ABIs, such as 64-bit hosts cross-compiling for MIPS, o32 is chosen to maintain compatibility with existing 32-bit software.

Beyond computing, o32 may appear as a model or internal code in various products or projects, where its meaning is defined by the context rather than a universal standard. Therefore, when encountering "o32," the surrounding documentation or platform specification should be consulted to determine its precise meaning.