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VPMOVSDB

Copies a byte string from a source memory location to a destination memory location. The number of bytes to copy is determined by the value in the rcx register. The instruction increments or decrements the source and destination pointers based on the direction flag (DF).

The following table describes the supported source and destination operands.

DO NOT support LOCK

This instruction is only available in 64-bit mode. It requires the rcx register to specify the count of bytes to be moved.

The instruction MUST be used with the rsi register as the source pointer and rdi register as the destination pointer. If the source and destination memory regions overlap, the behavior is undefined. The value of rcx is decremented after each byte transfer; the loop terminates when rcx reaches 0.