Visual Instruction Set (or VIS) is a SIMD instruction set used on the SPARC series of CPUs.
In hardware terms VIS is somewhat limited. It re-uses the existing floating point registers (like MMX) to hold multiple 8, 16, or 32-bit integer values. This can have a negative performance impact on the system, unlike more modern SIMD architechtures like AltiVec.
VIS includes a number of operations primarily for graphics support, but has more of them than other integer-only SIMD sets. These include 3D to 2D conversion, edge processing and pixes distance (for MPEG, pattern-matching support).