MUL - Unsigned Multiply

## Description

Performs an unsigned multiplication of the first operand (destination operand) and the second operand (source operand) and stores the result in
the destination operand. The destination operand is an implied operand located in register AL, AX or EAX (depending on the size of the operand).
The source operand is located in a general-purpose register or a memory location.

## Instruction

| Opcode        | Assembly  | Op/En | Modern Mode | Legacy Mode | Description                                                                  |
|---------------|-----------|-------|-------------|-------------|------------------------------------------------------------------------------|
| F6 /4         | MUL r/m8  | M     | Valid       | Valid       | Unsigned multiply (AX=AL*r/m8).                                              |
| REX + F6 /4   | MUL r/m8* | M     | Valid       | N.E.        | Unsigned multiply (AX=AL*r/m8).                                              |
| F7 /4         | MUL r/m16 | M     | Valid       | Valid       | Unsigned multiply (DX:AX=AX*r/m16).                                          |
| F7 /4         | MUL r/m32 | M     | Valid       | Valid       | Unsigned multiply (EDX:EAX=EAX*r/m32).                                       |
| REX.W + F7 /4 | MUL r/m64 | M     | Valid       | N.E.        | Unsigned multiply (RDX:RAX=RAX*r/m64).                                       |

- In 64-bit mode, r/m8 can not be encoded to access the following byte registers if a REX prefix is used: AH, BH, CH, DH.

## Information

The result is stored in register AX, register pair DX:AX, or register pair EDX:EAX (depending on the operand size), with the high-order bits of
the product contained in register AH, DX, or EDX, respectively. If the high-order bits of the product are 0, the CF and OF flags are cleared;
otherwise, the flags are set.

In 64-bit mode, the instruction’s default operation size is 32 bits. Use of the REX.R prefix permits access to additional registers (R8-R15).
Use of the REX.W prefix promotes operation to 64 bits.