Apricot XEN Pentium 60, Owner'S Handbook Manual, Page: 119 / 139

XEN OWNER'S HANDBOOK A/9
Inside the Apricot XEN
Appendix A
We can demonstrate that 3FB is exactly the same as 1019 by:
((256x3)+(16xF)+(1xB)=768+240+11=1019
Note
A lower case h is often used at the end of a number to ensure that
you realise it is in hex format e.g. 3FBh.
A larger hex number and one that you will come across in the
Memory map description below is A0000h. To see this as a
decimal number:
16x16x16x16 16x16x16 16x16 16 1
A 0 0 0 0
16x16x16x16=65536
So A0000h is 65536x10=655360.
If you have Microsoft Windows 3.x on your XEN you may find
it helpful to use the Windows Calculator. In Scientific View the
calculator allows you to enter decimal numbers and convert
them to hex, and vice versa.
Another commonly used notation is to describe numbers as x K
or x M. Where 1K=1024 and 1M=1048576
(1048576=1024x1024). In this notation 655360 (that is A0000h)
is 640K.
Memory maps
All memory, whether it is on the motherboard or an expansion
card, is accessed somewhere in the processor’s address space.
The processor’s address space can be thought of as a list of
locations, the locations are each identified by a number. The
first, or bottom, location is address 0.