Flexemu Monitor program V2.4


The monitor program provides basic I/O functions to the operating system. It is comparable to the BIOS on a PC.

But in addition it provides a simple command line interface to display or change memory contents or set, display or clear breakpoints.

This documentation describes the monitor programs V2.4 as deployed with flexemu as files mon24.s19 and mon24z.s19. It is designed to support the Eurocom II/V5. It does not have a FLEX boot loader. Instead files can be loaded from a Philips Mini Digital Cassette Recorder (Philips MDCR). See command D for details. Any command has to be entered in uppercase characters.

This monitor program overview shows which monitor program is best suited for which hardware configuration.

The following table gives an overview of the available commands:

Command Description
A Read and optionally modify CPU registers. Can be aborted by entering ESC. See also command B, C, K or S.
B XXXX Set breakpoint at address XXXX. Up to eight breakpoints can be defined. Only supported for an address located in RAM, so it does not work for address range F000 up to FFFF. At address 0000 no breakpoint can be set. See also command A, C, K or S.
B ENTER Display address of all eight breakpoints.
C Continue program execution at current PC location. Any CPU register, incl. PC can be changed with command A in between. See also command A, B, K or S.
D Read or write a file to or from a Philips Mini Digital Cassette Recorder (Philips MDCR). Two drives 0 and 1 are supported. There are four sub commands available:

L NAME06 XXXX YYYY
Load: Load a file from MDCR. The filename, a start- and end address has to be specified.

RN NAME06 XXXX YYYY
Record New: Rewind the cassette tape and write the file. All existing files on the tape get lost. The filename, a start- and end address has to be specified.

RO NAME06 XXXX YYYY
Record Old: Forward the cassette tape until the end of the last written file and write the file. All existing files on the tape are still available. The filename, a start- and end address has to be specified.

B
Back: Jump back to the command prompt.

flexemu comes with a cassette file system.mdcr. It contains the following files:

BASIC4 from $0000 to $39FF
DEBG64 from $8500 to $AFFF
E ZZ Switch the video graphics RAM. The following values are supported:

00: Video RAM from $0000 to $3FFF
01: Video RAM from $4000 to $7FFF
02: Video RAM from $8000 to $BFFF (Take care. $BF00 to $BFFF is the RAM area of mon24.s19 itself)

Any other value is ignored.
G XXXX Jump to address XXXX.
L NAME06 Load a file in Motorola S-Record format from serial port. This can be used with flexemu on Unix like operating systems by redirecting stdin to a S-Record file when starting flexemu on the command line. The name has to have exactly six characters. See also command R.
CTRL-L Clear screen.
M XXXX Display and modify memory at address XXXX. After displaying the memory content a new value ZZ can be entered. CTRL-J displays the memory content of the next address. The command can be aborted with ENTER or CTRL-X.
O XXXX YYYY Calculate address offset for a MC6809 branch or long branch operation.
P XXXX YYYY Command P: Details are unknown.
R XXXX YYYY NAME06 Write a file in Motorola S-Record format to serial port for the given address range incl. address YYYY. This can be used with flexemu on Unix like operating systems by redirecting stdout into a S-Record file when staring flexemu on the command line. The name has to have exactly six characters. It is stored in an S0 line. See also command L.
S Command S: Step over a breakpoint. See also command A, B, C or K.
T XXXX YYYY Memory dump from XXXX to inclusive YYYY.
V Terminal mode: Any input and output is sent or received from or to serial port.
/ Continue displaying memory content of next address based on a previous M command or address 0000.
. Continue displaying memory content of same address based on a previous M command or address 0000.
^ Continue displaying memory content of previous address based on a previous M command or address 0000.

Flexemu Monitor program file mon24z.s19

Monitor program mon24z.s19 has the same commands as mon24.s19. There is one additional command available in context of the emulation:

Command Description
Z Exit the emulator.

SEE ALSO

Documents on the behalf of the FLEX User Group

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