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VINSERTF128

Inserts 128 bits from a source operand into a destination XMM or YMM register. The insertion is controlled by an immediate value that determines whether the low 128 bits or the high 128 bits of the destination register are replaced.

The following table 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 AVX CPUID feature flag. When the destination is an xmm register, the immediate value SHALL be 0; if the immediate is 1, the behavior is undefined or may trigger an exception depending on the processor implementation.

To avoid unintended data corruption, ensure that the immediate value corresponds to the destination register size: use imm8 0 for the lower 128 bits and imm8 1 for the upper 128 bits (only applicable when the destination is a ymm register). Using an immediate other than 0 or 1 is invalid.