What is a far pointer? Where we use it?
What is a far pointer? Where we use it?
In large data model (compact, large, huge) the address B0008000 is acceptable because in
these
model all pointers to data are 32bits long. If we use small data model(tiny, small, medium) the
above address won’t work since in these model each pointer is 16bits long. If we are working in
a small data model and want to access the address B0008000 then we use far pointer. Far pointer
is always treated as a 32bit pointer and contains a segment address and offset address both of
16bits each. Thus the address is represented using segment : offset format B000h:8000h. For any
given memory address there are many possible far address segment : offset pair. The segment
register contains the address where the segment begins and offset register contains the offset of
data/code from where segment begins.
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