3.4.2 Data Movement Instructions

mov is used to copy data from a source to a destination. The source can be an immediate value (a constant), a register, or a memory location. The destination can be either a register or a memory location, but both cannot be memory locations simultaneously in a single instruction

<aside>

Suffix

• mov**b** (byte): 1 byte (8 bits)
• mov**w** (word): 2 bytes (16 bits)
• mov**l** (long): 4 bytes (32 bits)
• mov**q** (quad): 8 bytes (64 bits) </aside>

Zero extension vs Sign extension

Needed when going from a smaller register to a larger register. Ensures that the value in the smaller source operand retains its sign (positive or negative) when moved to a larger destination. z fills the extra bits in the larger destination with zeros. s fill the extra bits in the larger destination with zeros.