Documentation for M.COM/M.MAC
Purpose: Calling Apple monitor routines from PCPI CP/M
Created: 07/17/83 (Fred Meyer)

  M.COM is intended to be used in conjunction with MONCALL.DVR in
the PCPI Appli-card environment.  Installation consists of merely
installing MONCALL.DVR into the DRIVERS file of the boot disc.
Do not change the device number of MONCALL (currently #29) unless
you also change the MONDEVICE equate in the M.MAC file.  

  The monitor calling sytem was designed so that most of the code
resides in the 6502.  Only trivial routines are needed in the Z80.
This allows the monitor calling routine to be included in other
Z80 debuggers and utility programs with little programming.  If
� 0� i� sen� t� th� outpu� subroutin� o� devic� #29� the� th� �
monito� i� entered unconditionally�   Whe� i� th� monitor� 
B006� wil� re-ente� CP/� whereve� you left it.  No warm boot 
takes place.  To call a the monitor function directly, simply 
send the monitor string you want executed to the output subroutine 
of device #29, and set the hi-bit on the last character sent.  
The 6502 will handle setting of the hi-bits, linefeed supression  
and return to the Z80.  If an erroneous string is sent to the Apple, 
you will unconditionally enter the monitor.  However,  entering B006G 
will return you to wherever you were in the Z80.  Look at the M.MAC 
file to see how it works.

  All character input and output is through the current console I/O
device.  So if you have an external terminal, 80 column card or 70 
column SOFTVIDEO driver as the current console device, all monitor 
input and output will occurr through it.  Otherwise, the normal
Apple screen output is used.

  Normally, one would type "M <command>" at the CP/M command level
to execute <command> in the Apple monitor.  After displaying the 
results (if any) of the command, control is returned to the CCP.

  If ZCPR2 or another similiar CCP replacement is installed you may 
have a "GO" command.  This command normally executes the program
residing at 100h and passes any parameters to it which are typed after
GO.  Thus after running M.COM once, subsequent calls to the Apple 
monitor will be much faster if GO <command> is used, since no disk 
access is necessary.

  Multiple commands can be executed on one command line by separating 
them with an "N".  For example "M 8E00.8E20 N 9E00.9E20 N AE00.AE20"
would display on the current console 3 groups of 20h bytes.  However,
"M 5000:35 36 37 38 39" would display nothing since there is no 
outpu� expecte� fro� thi� monito� command�  (Nevertheless� 35h-3�h�
woul� b� store� starting at 5000h)

  To enter the monitor unconditionally, type "M<space><return>".
Any normal monitor commands can then be entered, with control always
returning to the monitor.  To re-enter CP/M type "B006G" at the "*"
prompt.  (Optionally B000G executes a cold boot and B01EG executes a
warm boot)

  A short tutorial will be displayed on the console if "M<return>"
is entered.  This may be useful occassionally as a syntax refresher.
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