Differences Vs X86
However VIS is not an instruction toolkit like Intel's MMX and SSE. MMX has only 8 registers shared with the FPU stack, while SPARC processors have 32 registers, also aliased to the double-precision (64-bit) floating pointer registers.
As with the SIMD instruction set extensions on RISC processors, VIS strictly conform to the main principle of RISC: keep the instruction set concise and efficient.
This design is very different from comparable extensions on CISC processors, such as MMX, SSE, SSE2, SSE3, SSE4, 3DNow!.
Sometimes programmers must use several VIS instructions to accomplish an operation that can be done with only one MMX or SSE instruction, but it should be kept in mind that fewer instructions doesn't automatically result in better performance.
Read more about this topic: Visual Instruction Set
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