Linux has stopped supporting the SIMD instruction set 3DNow! for AMD processors, writes Phoronix. The new 5.17 version of the Linux kernel has removed about 500 lines of code, which were responsible for running the said MMX extension, first released more than two decades ago.
The 3DNow! instruction set was released by AMD in 1998 along with the K6 3D processors, that is, 23 years ago. With it, the manufacturer wanted to gain superiority over processors made by Intel in the field of multimedia processing. 3DNow! technology introduced 21 new processor instructions and the ability to operate with 32-bit real types in standard MMX registers. Special instructions were also added to optimize switching to MMX/3DNow! mode and work with processor cache. So 3DNow! technology extended the capabilities of MMX technology without requiring the introduction of new CPU modes and new registers. In the late 90's and early 2000's this instruction set was heavily used by games, multimedia applications, and even Photoshop workflows. The 3DNow! instruction set was used from AMD K6 3D processors up to K10 (Phenom II) architecture. Shortly after AMD SSE instructions set for its own processors was released by Intel company. With release of Pentium 3 this instructions set became more popular, so by the moment of release of SSE2 AMD adapted it too. With the release of FX-series (Bulldozer) processors, AMD completely forgot about 3DNow! The last processors to support this instruction set were Phenom II. Nowadays, the main SIMD instruction set in AMD and Intel processors is SSE and its numerous variations (SSE2, SSE3, SSE4, SSE4.1, SSE4.2, SSE4A, SSE5 and others).