asm/reference

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PTWRITE



Writes a 64-bit value to a page-table entry specified by a linear address, ensuring the write is performed as an atomic operation if the memory is aligned.

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

source destination(s)
reg m8
imm m8

DO NOT support LOCK

The instruction SHALL only be executed in 64-bit mode. Execution in compatibility mode or 32-bit mode SHALL result in an invalid opcode exception.

To avoid unexpected behavior and potential memory corruption, the destination address MUST be aligned on a qword boundary. If the address is not aligned, the atomicity of the update to the page-table entry is NOT guaranteed, which MAY lead to inconsistent paging structures in multiprocessor environments.