movzxw
Move word with zero extension
Copies a word source into a register, filling added high bits with zeros when the destination is wider.
386 and later
CFPFAFZFSFDFOF –––––––
- Changes no flag
Forms
Operands
reg- The destination register. Its width is selected independently of the source width; widening uses a larger destination.
r/m16- A 16-bit general-purpose register or word in memory, for example
axorword [rsi].
It reads 16 bits and zero-extends them into a 32- or 64-bit destination. NASM also accepts a 16-bit destination; that copies the word without widening and preserves the remaining bits of the 64-bit register.
global _start
section .text
_start:
mov rax, 12
mov rbx, 5
mov rcx, 3
mov rsi, 9
movzxw rax, bx
mov rax, 60 ; syscall 60: exit
xor rdi, rdi
syscall