(optional)
is a data, base or index register. More than one dreg may be used to define
a displacement from the segment register value to the memory location. It
is one of:
BP, SP, SI, DI, AX, BX, CX, DX
nnnnn
(optional)
is an optional fixed displacement to be added to the address calculated
in the registers. If hex the syntax is 0xnnnn.
iiiii
(optional) is a displacement from the indirect address.
If hex the syntax is 0xiiii. This specifies a displacement from the final
address when using INDIRECT or IF (Indirect Flat) addressing.