MZ-700 monitor 1Z-013A
The 64 kbytes RAM of the MZ-700 are free and not allocated after power on / RESET. A program to be executed must be loaded first into the storage by the data recorder, a disk drive, or manually by the keyboard. The monitor program is needed to load the program to be executed. It is resident in a 4 Kb ROM and it does the work like a boot loader or an IPL ( Initial Program Loader ). The monitor program 1Z-013A is activated after power on first and the blinking cursor waits for your input command ( see screenshot above).
The monitor can be used too to change programs, to enter new programs, to modify the storage, to print or plot a character string, and to test programs.
The following monitor commands are available and described in detail
later in this section:
The contents of the monitor's work area shows the following table:
| Detailed syntax of the monitor commands
Commands will be executed when you entered the command and afterwards the enter key CR was pressed. Numerical values must be entered in hexadecimal notation. Don't use spaces and don't omit preceding zeroes. Please select one of the following commands to see the syntax of the command:
| Load command
L loads the next machine code file found on tape.
The monitor will response:PLAY
if the PLAY button isn't pressed at this time.
To premature end the load process you can press SHIFT and BREAK coincidentally.
| Print / Plot command
Syntax: PHELLO WORLD
The plotter will plot "HELLO WORLD"
The plotter performs its self test. The response at the
The plotter is set to plot 80 characters per line.
The plotter is set to plot 40 characters per line.
The plotter is set to the graphic mode.
The plotter changes to the next color pen.
| Memory modification
This command modifies the contents of the storage starting at the location
To end the input mode press now SHIFT and BREAK coincidentally. The storage from the location $B000 to $B003 is changed.
The monitor displays the current storage address and the contents of the current storage address. You can enter any 2 digits hex value at the cursor position. If you press CR immediately without entering any value, the memory will not be changed. The monitor displays the last address once more if there was any error during the last input.
| Dump / display command
This command displays the contents of the storage from aaaa to eeee on the screen. A block of 160 bytes is displayed if you omit the end address ( eeee ). The format is dump as follows:
The area to be displayed is from $C000 to $C008.
The monitor stops displaying at $C007. If you want to see the area from $C000 to $C008, you should type in: DC000C009. There is one byte left and it works as designed.
C000 is followed by 8 hex characters which represent the contents of the storage in hexadecimal notation. The monitor tries to translate these values to the MZ-700 ASCII code. If the monitor finds a non displayable character ( see the $00's ) then a decimal point is displayed by the monitor.
If the end address ( eeee ) is less than the start address or equals to the start address ( aaaa ) the listing from aaaa does not end until you press SHIFT and BREAK coincidentally. The listing has no real end address. The same will take effect if the end address is incorrect, for example, a non hex character was entered at the end address.
You can pause a complex, long listing by pressing the space bar until you depress the space bar. You can get a slower listing speed by pressing the SHIFT key until you depress the SHIFT key.
| Jump command
The program at the location aaaa will be executed. The monitor transfers the control to this program. Example to start a program with its entry point at $C000:
Don't use the assembler RET command to return to the monitor, unpredictable results can occur if you use the same stack in your program and if you don't set up the stack before returning to the monitor. Use the following commands instead of the assembler RET command to return to the monitor program:
LD SP,$10F0 ; re-initiate monitor's stack JP $00AD ; goback to monitor
For further information download the reassembled monitor program.
| Save command
aaaa is the starting address of the
area to be saved
The user saved the program with the name MYPROG that starts at the location $C000 and the save will stop saving at the location $C2FF. The program is to start automatically after the next load by the monitor from the address $C000 ( entry point address ). The file attribute will be $01 ( machine code program ). For further information about all information of the file stored on tape click here.
When the save command is entered, the monitor requests for the file name. Then the user was prompted to press the RECORD button and the PLAY button coincidentally at the data recorder and then the save process was started by the monitor. The monitor response was: "WRITING MYPROG" and at the end of the save process the monitor's response was: "OK!".
Don't forget to insert the right tape at the right position before
you press the keys at the data recorder
You cannot save BASIC programs by this command. You can save only the machine code of your program and its data areas. The load routine always sets the attribute byte of the file to $01 and this is the attribute of a machine code program. The load process of BASIC ignores machine code programs, it is searching only for BASIC programs whose attribute byte is set to $05.
If you want to suppress the autostart function, then set the execution address ssss to $00AD or $0000. Note, if you use $0000 the MZ-700 will be reset.
To premature end the save process you can press SHIFT and BREAK coincidentally. In this case wait until the monitor stops saving and sometimes you have to try it again and again.
| Verify command
The program in the storage and the program on tape will be verified by the monitor. This command will only work well immediately afterwards of a save process that was fully completed!
If you have saved a program by the save command you have to rewind the tape to the start position of the file just saved and then to execute the verify command. The process is as follows:
*V PLAY OK
You've entered the verify command and the monitor has prompted you to press the PLAY button at the data recorder. The monitor verified the program and has stopped with the message: "OK".
If the monitor detects any errors, you'll get the error message: "CHECK SUM ER.". In this case try again to save the program and try to use a better tape.
To premature end the verify process you can press SHIFT and BREAK coincidentally.
| The #-command
The command # has the same effect like pressing the RESET key at the reverse side of the MZ-700 and the CTRL key coincidentally. The program at location $0000 in the RAM will be executed. For further detailed information click here. This command is used normally to return to BASIC after you've used the BASIC command BOOT or after you've pressed the reset key while BASIC was active ( or another program having the entrypoint address $0000 ).
| Bell command
If you enter the bell command you can hear a short beep tone over the loudspeaker while pressing any key. If you enter the beep command again, the beeping will be stopped.
| Floppy disk access
If you type in the command F the monitor checks the byte at location $F000. If the value of this byte is $00 the control is transferred to $F000, otherwise the monitor ignores the command. Source: see the monitor's program at location $00C9 and then $00FF.
This function can be used for some own purposes too. Connect your own ROM or RAM and put $00 to this location and use the F command to start your own application from this location. $00 is a NOP only.