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SUB

Subtracts the source operand from the destination operand and stores the result in the destination.

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

Support LOCK

The instruction is supported in 64-bit mode, 32-bit mode, and 16-bit mode. When operating on memory, the destination MUST NOT be a constant.

The EFLAGS register is updated based on the result: CF is set if there is a borrow-out of the most significant bit; ZF is set if the result is zero; SF is set if the result is negative; OF is set if a signed overflow occurs. Users SHOULD ensure the operand sizes match to avoid unexpected truncation or extension of values. When using SUB with a memory destination, the operation IS atomic if the LOCK prefix is applied and the memory operand is aligned.