NOMAD

An Full Screen LCD Editor For Model 100/102 BASIC

Copyright 1989 Howard Sprow CIS:73625,365




NOMAD.CO is a machine language enhancement to the M100/102 BASIC interpreter 
which allows you to move anywhere on the LCD screen to adjust a previous 
command and re-enter it. The lack of this feature has long been a frustration 
to M100/102 users. You mistype a long command. It's there just above your 
cursor but you can't move up to correct it so you have to retype the whole 
command.

With NOMAD, just press F6 to move the cursor up on the screen to correct 
and re-enter the command. For a quick change to a program line, LIST the 
line and use NOMAD to make corrections without waiting for the BASIC edit 
mode to load.


NOMAD FILES

The program consists of the following files:

    NOMAD.LDR - BASIC loader program which creates NOMAD.CO. Store in 
your M100/102 as NMDLDR.BA.

    NOMAD.BA - BASIC starter program to initialize NOMAD

    NOMAD.SRC - assembly language source code for NOMAD.CO. This will 
be of interest to ML programmers but is not necessary to run NOMAD. NOMAD 
was assembled with the Custom Software Assembler.

    NOMAD.DOC - this documentation file


INSTALLING THE PROGRAM

Run NMDLDR.BA (NOMAD.LDR) from BASIC to create NOMAD.CO and place it on 
the main menu. Then, run NOMAD.BA. This loads a copy of NOMAD.CO into 
high memory at address 62400 and define the F6 key as CALL62400+[ENTER]. 
F6 is then used to activate NOMAD from BASIC with only one key stroke. 
You can enter BASIC each time by running NOMAD.BA but this is not absolutely 
necessary if you always leave a copy of NOMAD.CO at 62400. As long as 
HIMEM is not reset from 62400 (i.e., with a CLEAR command from the BASIC 
command line or from within a program) NOMAD will remain in high memory.

NOMAD.BA does not simply clear memory and load NOMAD.CO each time it is 
run. If HIMEM is already set at 62400, NOMAD.BA verifies that the NOMAD.CO 
code is present starting at 62400. If it is, NOMAD.CO is not reloaded 
from its menu position. This allows you to leave NOMAD in high memory 
at 62400 and remove it from the main menu to free up additional RAM.


USING NOMAD

With NOMAD loaded at 62400, whenever you need to edit a previous command 
which is still visible on the LCD screen, simply press F6. The NOMAD name 
will be displayed on the bottom line and the cursor will be positioned 
in the upper left corner. Use the cursor keys to move anywhere on the 
screen.

NOMAD provides a simple screen editor. Insert mode is always active. The 
DEL/BKSP key is used to remove characters just as in TEXT. No word wrap 
is provided.

Once you have adjusted the line so it is ready for entry, there are two 
rules which must be followed.

1)Place the cursor anywhere on the first screen line of the entry.

2)Press ENTER once and the cursor will jump to what NOMAD thinks is the 
end of the entry. NOMAD identifies the end by looking for the first two 
adjacent blank spaces. If this is the correct ending position, press ENTER 
a second time and the entry will be processed and the M100 will return 
to normal BASIC. If this is not the intended end, move the cursor left 
or right so that it is one position to the right of the last character 
and then press ENTER a second time.

Most direct BASIC commands will have no internal double spaces, so a quick 
double press of the ENTER key will accept the entry. Program lines often 
will contain double spaces, so check the end position before pressing 
ENTER the second time.

After the first press of ENTER, you are in NOMAD's "enter mode". Pressing 
ESC once aborts this enter mode and moves the cursor to the upper left 
of the screen. At this point, NOMAD is still active in the "edit mode". 
Pressing ESC again will deactivate NOMAD and return you to normal BASIC.


EDITING PROGRAM LINES

With NOMAD you are not limited to changing and re-entering only BASIC 
commands. NOMAD is also a quick way to fix program lines without going 
into the BASIC editor. Just LIST the appropriate line, activate NOMAD 
with F6 and make your changes. Press ENTER twice as described above to 
accept the revised line.


USING ANOTHER FUNCTION KEY TO ACTIVATE NOMAD

NOMAD has been set up to be activated with F6. To use another function 
key, change the value of the variable, FK, in line 3 of NOMAD.BA from 
"6" to another function key number. Then, save a copy of your modified 
version of NOMAD.BA on disk or tape.


COMPATIBILITY WITH OTHER ML PROGRAMS

NOMAD was designed as a standard machine language program which is stored 
in a normal low memory, "menu" position and is run from a high memory 
location. It is started with a standard CALL command and does not use 
any RAM hooks. This approach permits the greatest compatibility with other 
ML utility and DOS programs many of which use RAM hooks and/or a low memory 
operating position.

If you use another machine language program which must run from the top 
RAM position, you can reactivate NOMAD each time by running NOMAD.BA or 
you can relocate NOMAD.CO to a lower operating RAM position under your 
other ML program.

One of the ML program relocators, such as RELOC.BA in Library 8, is a 
simple way to move NOMAD to a another operating position. NOMAD requires 
at least 541 bytes and does not include any data tables. It does use two 
RAM positions for temporary data storage but these are included as part 
of the program code, within the 541 byte requirement.

If you relocate the machine language portion of NOMAD, you must change 
the NOMAD.BA program to show the new start address. Do this by changing 
the value of the variable, TP, in line 1 and save a copy to disk or tape.

Using the standard CALL command to activating NOMAD as compared to using 
RAM hooks has one disadvantage but it insures compatibility with other 
ML programs which use RAM hooks, specifically the various DOS programs. 
If you press F6 to activate NOMAD with the cursor on the bottom screen 
line, the screen will scroll up one line, thereby losing any characters 
on the top line. Keep this in mind when you edit.


MISC.

With only one exception, NOMAD can accept all types of entries from the 
LCD in the same format as would be used from the normal BASIC command 
input line. When setting the system variables, TIME$, DATE$, DAY$, when 
in NOMAD you must include a double quote at the end of the string or the 
entry will result in a "?SN" error. Even though a closing quote is proper 
syntax, entering these variables without it does not generate this error 
in normal BASIC.

Once F6 has been defined as CALL 62400+[ENTER], NOMAD does not automatically 
deactivate this definition when you leave BASIC. Therefore, it is important 
 that you remember not to press F6 if NOMAD has been removed from high 
memory or a cold start could result.