NASM Coding: Common Instructions

Here are many of the instructions that we will used in our NASM programs, and their description:

Instruction Description Operands 
add x, y
 
x += y;
 Numbers as registers or variables (
y
can also be a literal)		 
and x, y
 
x &= y;
 Registers or variables (
y
can be a literal); they will be bitwise ANDed		 
cmp x, y
 Is 
x == y
?		 Registers, variables, or literals; the OS sets the sign, zero, carry, and overflow flags 
dec x
 
x -= 1;
 Register or variable 
div x
 
rax:rdx /= x;
 Register, variable, or literal; unsigned integer division; quotient is put in 
rax
and remainder in 
rdx
by the OS		 
idiv x
 
rax:rdx /= x;
 Register, variable, or literal; signed integer division; quotient is put in 
rax
and remainder in 
rdx
by the OS		 
imul x
 
rax:rdx = x * rax;
 Register, variable, or literal; signed multiplication 
imul x, y
 
x *= y;
 
x
is a register and 
y
is a register or variable; signed multiplication		 
imul x, y, z
 
x = y * z;
 
x
is a register; 
y
is a register or variable; 
z
is a numeric literal (e.g., 
5
); signed multiplication
These notes by Miriam Briskman are licensed under CC BY-NC 4.0 and based on sources.