X86-assembly/Instructions/cmp

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X86-assembly

Instructions

cmp

Description

• The cmp instruction is used to perform comparison. It's identical to the sub instruction except it does not affect operands.
• It impacts the Zero Flag (ZF) as well as the Carry Flag (CF) as follows:

cmp dst, src	ZF	CF
dst = src	1	0
dst < src	0	1
dst > src	0	0

Syntax

cmp destination, source

Example

cmp [ebp+arg_0], 1     ; compare 1 with [ebp+arg_0]
jnz short loc_402B1D   ; Jump short if not zero (ZF=0)