MOV

Table of Contents

1. MOV
2. MOV (mov)
   1. Basic purpose
   2. Instruction format
   3. Behavioral characteristics
   4. Equivalent analysis
   5. Common uses

MOV

MOV (mov)

Basic purpose

The MOV instruction is used to copy the value of the source operand to the destination operand.
This is one of the most commonly used instructions for data transfer.

Instruction format

1
mov dst, src
2
dst = src

Allowed:

• Register ← Register
• Register ← Memory
• Memory ← Register
• Register ← Immediate
• Memory ← Immediate Forbidden:
• Memory ← Memory

Behavioral characteristics

• Different alignment and size selections may trigger automatic extension (such as movzx, movsx)
• Does not modify EFLAGS (important)
• Can perform zero extension (mov r32 → automatically clears the upper 32 bits)

Example:

1
mov eax, [rbp-0x10]
2
mov [rbp-0x8], rax
3
mov ecx, 0x1234

Equivalent analysis

MOV is a pure data copy operation and can be regarded as:

1
dst = src

Understanding MOV is very helpful for mastering function argument passing and register behavior under the ABI.

Common uses

• Passing variables
• Initializing registers
• Changing pointer positions
• Saving and restoring values