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

PMADDUBSW

Multiplies unsigned 8-bit integers from the first source operand by signed 8-bit integers from the second source operand, adds the adjacent pairs of products to a signed 16-bit result, and stores the results in the destination operand.

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

DO NOT support LOCK

This instruction is only available when the processor is operating in 64-bit mode or compatibility mode and requires the SSE4.1 extension. It operates exclusively on XMM registers.

The operation performs saturation on the 16-bit signed integer sums; if the result of the addition exceeds the range of a signed 16-bit integer, it is clamped to the maximum or minimum representable value (i32: -32768 to 32767). Failure to account for this saturation behavior may lead to logic errors in signal processing applications expecting wrap-around arithmetic.