Table of Contents
Advertisement
Encoded
in the
Instruction
Explicit
in the
Instruction
Assumed Unless
Overridden
by Prefix
The displacement is an 8- or 16-bit number contained in the instruction. The displacement gen-
erally is derived from the position of the operand's name (a variable or label) in the program. The
programmer can modify this value or explicitly specify the displacement.
OVERVIEW OF THE 80C186 FAMILY ARCHITECTURE
Single Index
BX
or
BP
or
SI
or
DI
+
+
Figure 2-12. Memory Address Computation
Double Index
BX
or
BP
+
Displacement
+
0000
CS
or
SS
0000
or
DS
0000
or
ES
0000
+
Physical Addr
SI
or
DI
EU
Effective
Address
BIU
A1015-0A
2-29
Advertisement
Table of Contents
