Monitor Rom Routines - Zenith Z-100 Reference Manual

Monitor ROM Routines

Another feature of your computer is the collection of monitor ROM routines. While
these routines are primarily designed for use in writing, testing, and debugging
machine language programs, some of the commands and features can provide
an efficient means of locating hardware problems. Use of these routines assumes
you have a knowledge of programming the 8088 microprocessor at the assembly
level and an understanding of terminology associated with this level of program-
ming, such as "flag," "register," "pointer," "bit," "byte," and so on.
The commands and features of this package are comprised of a substantial portion
similar to the DEBUG utility supplied with MS-DOS. Among the more useful
utilities induded are the abilities to:
Boot an operating system from a disk drive
Display the contents of memory
Execute a program
Set program breakpoints
Input or output values to or from VO ports
Search memory f or a byt e p
Disassemble user program memory
Change video and scrolling modes
NOTE: Because of the interrupt driven nature of the keyboard, user-written pro-
grams must incorporate commands to enable interrupts or the keyboard informa-
tion will not be recognized by the microprocessor. Programs performing I/O
through the ROM firmware already meet this requirement as the ROM routines
automatically enable interrupts for short periods of time.
Connnand Summary
To use the ROM routines, the system prompt arrow (->) must be displayed.
This means the Disk Operating System (DOS) must not have been booted up
or you must exit the operating system to the monitor prompt by pressing the
CTRL-ALT-INS keys. The following functions and commands will then be available.
NOTE: Range in the following statements is address, address, ~ Uength and
List is byte ~ "string".
System Operating Features
attern
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