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PSHUFW

This instruction shuffles 16-bit words from a source XMM register based on an immediate byte. For each word in the destination, the instruction selects a word from the source XMM register as specified by the corresponding 2-bit field in the immediate.

The table below covers what the source and destinations can be.

DO NOT support LOCK

This instruction is only available in 64-bit mode or compatibility mode. It requires the SSE2 instruction set extension.

The immediate value is used as an index; if the 2-bit field in the immediate specifies an index that exceeds the number of words available in the source register (index $\ge$ 8), the resulting word in the destination is set to zero. This behavior is critical to avoid unexpected data leakage or garbage values when using immediate indices.