User's Manual

80286 BASE ARCHITECTURE
r--------,
20000 CS
MAIN
PROCEDURE
0 _____ ...
0 _____ ...
2000 ~----..,
o ___ ~- ...
O~""';""'; _ __I
L _______ ...J
CURRENTLY
ACCESSIBLE
8000 r-----..,
PROCEDURE
A
O~ ___ __I
7253051
DATA (A)
L..- __ --I
8600 r-----.,
0'"- ____ ..1
I
DATA (B)
0 .. ____ --1
Figure 2-1. Segmented Virtual Memory
G3010B
A byte is 8 contiguous bits starting on an addressable byte boundary. The bits are numbered 0 through
7, starting from the right. Bit 7 is the most significant bit:
o
I I i
BYTE
, I
A word is defined as two contiguous bytes starting on an arbitrary byte boundary; a word thus contains
16 bits. The bits are numbered 0 through 15, starting from the right. Bit 15 is the most significant bit.
The byte containing bit
0 of the word is called the low byte; the byte containing bit 15 is called the
high byte.
15 0
I : : ~IGH:B+: : I : : +W:BY+: : I
LOCATION N + 1
LOCATION N
2-2