MIPS64

MIPS64 is the 64-bit extension of the MIPS architecture. It introduces a 64-bit general-purpose register file and 64-bit addressing, enabling larger virtual address spaces and 64-bit data paths while preserving the core RISC design and programming model of MIPS.

Architecture and features: MIPS64 provides 64-bit general-purpose registers and, where implemented, a 64-bit floating-point unit. It supports the standard MIPS load/store and arithmetic instruction patterns, extended to operate on 64-bit operands. Many MIPS64 implementations offer a mode to execute 32-bit MIPS instructions for backward compatibility, with separate 64-bit and 32-bit execution contexts. Different implementations may support various ABIs, with LP64 (where longs and pointers are 64-bit) being common on Linux-based systems.

Implementation history: The 64-bit MIPS lineage began with early 64-bit processors such as the R4000 family and continued through subsequent generations (e.g., R10000 and others). In the 2000s, the architecture was formalized and marketed as MIPS64, with continued development by MIPS Technologies and its successors. Hardware featuring MIPS64 appeared in a range of products, including servers, embedded systems, and networking equipment.

Software ecosystem and usage: Linux, NetBSD, and other Unix-like systems have supported MIPS64, along with select other operating systems over time. In practice, MIPS64 has found use in specialized markets such as routers, storage devices, and certain professional computing platforms. While 64-bit MIPS remains relevant in some niches, mainstream server and consumer ecosystems have largely shifted toward other 64-bit architectures.