How Intel's MMX Brought SIMD to the PC

SIMD in the 90s: Programming Intel's Pentium MMX

In 1997, Intel introduced MMX, a set of 57 SIMD instructions that let a Pentium process multiple data points with a single instruction. This article looks back at MMX's design—reusing the x87 floating-point registers—and its impact on multimedia software. It explains packed integer data, saturating arithmetic, and the EMMS instruction, and shows how MMX enabled optimizations like processing eight pixels at once. The piece also clarifies the difference between SIMD and vector processors, noting that SIMD predates MMX by decades.