Macro Function for Shuffle

The Streaming SIMD Extensions 2 provide a macro function to help create constants that describe shuffle operations. The macro takes two small integers (in the range of 0 to 1) and combines them into an 2-bit immediate value used by the SHUFPD instruction. See the following example.

You can view the two integers as selectors for choosing which two words from the first input operand and which two words from the second are to be put into the result word.