Intel 386 User Manual page 444

Example 4
This example establishes two 16-Kbyte address blocks starting at 0E08000H and 0E28000H (16-
Kbyte boundaries).
15-bit Channel Address
15-bit Channel Mask
Channel Active Address
Because the least-significant 0 in the channel mask is in bit position 4, this channel's active ad-
4
dress block size is 2 = 16 Kbytes. Because there is one 1 to the left of the right-most 0 in the
channel mask, the address block is repeated 2
in the channel mask where there is a 1 in the channel address. For this reason, the channel address
is not the starting address of the lowest active address block. In this example, each active 16-
Kbyte address block is followed by an inactive 16-Kbyte address block and each block starts at
a 16-Kbyte address boundary.
15
0 0 1 1 1 0 0 0 1 0 1 0 0 0 0
0 0 0 0 0 0 0 0 1 0 0 0 1 1 1
25
0 0 1 1 1 0 0 0 X 0 1 0 X X X
1
= 2 times. Unlike the other examples, there is a 1
Memory Address
0E2C000H
0E2BFFFH
Active
0E0C000H
0E0BFFFH
Active
CHIP-SELECT UNIT
1
X X X X X X X X X X X
Maximum
0E28000H
0E08000H
0
14-9