This content has not been validated; it was AI-generated following the x86-64 ISA Documentation generation process to maintain high quality. However, as no human has verified this data, errors may exist. If the accuracy of this data is critical, please consult the Intel SDM. The model used to generate this is gemma4:31b

PMULHW

Multiplies two signed word-size elements from two XMM registers and stores the high 16 bits of the result in the destination register.

The table after the description covers what the source and destinations can be.

DO NOT support LOCK

This instruction is available in 64-bit mode and 32-bit mode. It requires the SSE4.1 instruction set extension.

The destination register is overwritten; therefore, the destination register MUST NOT be used as a source if the original data is required. Failure to account for this will result in the loss of input data.