what do you mean sir ??
afaik mul is always mul source

never heard of two operators on mul
it always multiplies what is on al,ax,or eax by the source and leaves the result in ax,eax, and eax:edx
MUL source
Logic AX . AL * source ; Source is a byte
or
DX:AX . AX * source ; Source is a word
or
EDX:EAX . EAX * source ; Source is a dword (386+)
MUL performs unsigned multiplication.
The carry and overflow flags (CF and OF) are set to 1 if the
high-order of the result (AH,DX, or EDX, respectively) contains
any significant digits; otherwise, CF and OF are reset to 0.
Opcode Format
F6 /4 MUL r/m8
F7 /4 MUL r/m16
F7 /4 MUL r/m32