Multiplication & Division

Multiplication

x86_64 has two multiply instructions:

IMUL (Signed Multiply)

The most common form:

imul rax, rbx        ; rax = rax * rbx
imul rax, rbx, 5     ; rax = rbx * 5

MUL (Unsigned Multiply)

One-operand form that uses rax implicitly:

mul rbx              ; rdx:rax = rax * rbx

The result is 128 bits, split across rdx (high) and rax (low).

Division

IDIV (Signed Divide) and DIV (Unsigned Divide)

Division also uses implicit registers:

; Before dividing, sign-extend rax into rdx:rax
cqo                  ; sign-extend rax -> rdx:rax
idiv rbx             ; rax = rdx:rax / rbx, rdx = remainder

For unsigned division:

xor rdx, rdx        ; zero rdx (unsigned, no sign extension)
div rbx              ; rax = rdx:rax / rbx, rdx = remainder

Important: You must set up rdx before dividing! Use cqo for signed or xor rdx, rdx for unsigned.

Your Task

Compute and print:

1. 3 * 3 = 9
2. 8 / 2 = 4
3. 7 % 3 = 1 (remainder)

Print: "9\n4\n1\n"