Programming User Memory - Zenith Z-100 Reference Manual

Programming User Memory

In general, programming user memory is very simple and straightforward. Most
of the access operations can be performed directly from the built-in ROM routines
or from assembly level programs written using the Programmer's Utility Pack
Typical memory access operations indude:
Reading and writing to specific memory locations
Allocating specific sections of memory to dedicated purposes, such as often
used programming routines or user-defined character storage
Storing repetitive character and numeric strings
Rerouting useful interrupt vectors
Stack operations
Moving memory contents from one area to another
Using RAM contents to control video graphics
In addition to normal RAM manipulation, you have the ability to disable parity
generation and/or checking, either for diagnostic checks of the system, or any
other purpose you might have which does not require, or for which you do not
desire, parity checks to be made.
Memory Address Format
The notation recognized by the 8088 microprocessor for specific memory location
access is a two-part parameter consisting of a 4-digit hexadecimal number called
the segment, and a 4-digit hexadecimal number called the offset The format for
this value is:
The first four digits actually represent a 5-digit hexadecimal number, since an
imaginary shift left (multiply by 16) is performed on the value to arrive at the
RAM bank and row to select.
The second value selects the RAM column from the selected bank
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System Memory