x86

x86 is a family of instruction set architectures based on the Intel 8086, introduced in 1978. The name derives from 8086/8088, and it has become a label for a broad lineage of CPUs and software compatible with the original 16-bit instruction set. The architecture evolved from 16-bit to 32-bit with the 80386, and to 64-bit with the AMD64 extension later adopted by Intel as Intel 64.

Origin and architecture: The 8086 introduced segmented addressing and a 16-bit data path. Successive generations added protected mode and larger address spaces, culminating in 32-bit flat memory and paging with the 80386 and beyond. x86 is a CISC design with variable-length instructions, many addressing modes, and a compact core set of general-purpose registers that expanded from eight 16-bit registers to 32-bit and then 64-bit variants (RAX, RBX, etc.).

64-bit era and extensions: The 64-bit extension, AMD64 (also called x86-64), preserves backward compatibility with 32-bit software while extending registers, addressing, and performance. Intel later adopted it as Intel 64. Modern x86 CPUs include SIMD extensions such as MMX, SSE, AVX, and AVX-512, hardware virtualization features, large caches, and out-of-order execution.

Impact and status: x86 remains dominant in personal computers and many server systems, supported by major OSes like Windows and Linux. It faces growing competition from ARM in mobile and embedded devices. Ongoing development focuses on performance, power efficiency, and ecosystem compatibility, ensuring continued relevance through backward compatibility and system-level optimizations.