äNote:
äSegments create the possibility of many ways to address the same memory location
äFor ex: Suppose the
memory location is 10028Hex
äThe following all
reference the same cell
ä1000:28, 1001:18,
1002:8, 0FFF:38
äFor ex: 1000:28
=> 10000 + 28 = 10028
äAs a result 20 bit addresses never appear in an instruction (or the assembly language), we always use a 16 bit segment and 16 bit offset
äHow does the 8088
use segments?
äMemory access (including instruction fetching) is performed using one of the segment registers as the segment value and an operand as the offset
äinstruction fetch CS:IP
ädefault data access DS:offset operand
ädefault stack access SS:SP
äCreates 64K windows with exact memory locations determined by value in segment registers