home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Loadstar 26
/
026.d81
/
t.memory window
< prev
next >
Wrap
Text File
|
2022-08-26
|
3KB
|
191 lines
MEMORY WINDOW
by
Carl Thompson
COMMODORE MICROCOMPUTERS MAGAZINE
July/August, 1986
p. 98
When you first run MEMORY WINDOW,
you will be forgiven if you think
for a second that you are in the
middle of some strange arcade game.
After all, just WHAT are those
undulating white blobs DOING on that
jet black background?
Well, put away your joysticks;
something a little more serious (and
educational) is afoot. MEMORY WINDOW
lets us peek into the inner recesses
of our Commodore's memory. Each
speck of white represents a memory
"bit" that contains a "1" (ON); each
black space represents a "bit" that
has a "0" (OFF).
(OK! A special quickie tutorial....
A "bit" is a single unit of computer
memory. Eight bits make up a "byte";
256 bytes make up a "page". It's
really more complicated than that, of
course, but more detailed information
is readily available if you're
interested.)
By pressing the CURSOR-UP and
CURSOR-DOWN keys, you can scroll
through page "0" to page "63", or you
can jump from page to page by typing
in the number of the page you wish to
view. Note that MEMORY WINDOW has 84
rows and that each row contains three
bytes, or 24 bits.
THE MEANING OF IT ALL.....
No guided tour of the C-64's memory
would be complete without some
insightful commentary. Here is a page
by page account of what you are
seeing:
PAGE 0-- You will see a lot of
blinking on this page-- the C-64's
microprocessor makes heavy use of its
memory locations. In fact, you can
even stop MEMORY WINDOW by pressing
the RUN/STOP key and the blinking will
continue. This is because a computer
really never rests-- it executes
hundreds of thousands of instructions
every second-- whether it's running a
program or not.
To restore the program, clear the
screen by pressing the SHIFT-CLR/HOME
combination, then typing in "RUN" and
pressing RETURN.
PAGE 1-- This page has a great deal
of activity at the bottom of the
page. This page, called the "stack",
is a temporary storage area.
PAGE 2 and 3-- These pages contain
many of the pointers and buffer
storage areas used by the Kernal
operating system and the BASIC
interpreter.
PAGE 4-7 -- These pages are used as
the standard location for the numbers
used to create the text on the screen.
PAGE 8-- Page 8 is the beginning of
the BASIC program area.
PAGE 13-15 -- For the MEMORY WINDOW
program, variables are stored
beginning at page 13, arrays at page
14. Arrays end at page 15.
PAGE 16-31 -- These pages are
available for text strings, but
because this program uses sprites,
they are used for the character ROM
image.
PAGE 32-64 -- These pages are
currently available for text string
storage.
DISK FILE USED:
MEMORY WINDOW
-----------< end of text >------------