© Thomas Kunz 2000
SCE 574
77
8088 Addressing
Modes
Modes
äAddressing
modes identify the system registers to be used as source and destination
operands
äModes
äMemory:
operand is in a memory location
äImmediate:
operand is part of instruction (constant)
äRegister:
operand is a processor register
äMemory
modes: operand is in a memory location
ä(1)
Direct
äaddress
of operand is part of instruction
ä(2)
Indirect: use register contents + direct information
(a) register - offset is
in one of BX, BP, SI, DI (a default register is assumed)
(b)
based DS:BX + 16 bit displacement (Sets up default)
(c
i) indexed DS:SI or DI + displacement
(c
ii) indexed ES:SI or DI + displacement
(d
i) based indexed DS:BX + SI or DI + displacement
(d
ii) based indexed SS:BP + SI or DI + displacement