Commodore Plus 4 - Page 246

234 Machine Language on the Commodore Plus/4
displayed. If the end address is not specified, 96 memory locations are displayed.
If no addresses are specified, the memory dump begins one location beyond the
last location accessed. Thus, memory is continually dumped 96 locations at a time
when you enter the M command repeatedly.
The memory dump is displayed on the screen preceded by a greater-than sign
and by the address at which the line starts. Because the greater-than sign is used to
change memory locations, cursoring to a dumped line, changing the desired
memory location(s), and entering a RETURN is a good way of altering the
contents of memory. If you attempt to alter ROM locations in this way, the
contents of the ROM are redisplayed. The RAM under the ROM will be altered.
Example: M 80CP 80D7
>80CF 43 4F 4D 4D 4F 44 4F 52
>80D7 45 SO 42 41 53 49 43 20
Note: Text that would be displayed in reverse mode on your screen is shown
boxed in this book.
The monitor is asked to display the contents of memory locations $80CF through
$80D7. It displays the contents in hexadecimal and as characters.
Changing Memory—The > Command
The > (greater-than sign) command is used to change the contents of memory.
The syntax is as follows:
> address data
The address is the starting address for the memory change.
The data are 1 to 8 hexadecimal bytes of data separated by spaces to be placed
in memory.
The monitor places the specified data bytes into memory starting at the
specified address. If more than 8 data bytes are specified, the excess is ignored.
After placing the bytes in memory, the monitor displays the contents of the
memory as in the M (Memory) command. If ROM locations are specified the
data are placed in the RAM underneath, but the contents of the ROM are
displayed.
Example: >2000 43 59 4E 44 49 45 20 4D
results in the following display:
>2000 43 59 4E 44 49 45 20 4D :1CYKTDIE M|