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ced 1.0 User's Guide
Table of Contents
Purpose . . . . . . . . . . . . . . 1
System Requirements . . . . . . . . 1
Terminology . . . . . . . . . . . . 1
Installation . . . . . . . . . . . . 2
Command line editor . . . . . . . . 2
DOS command stack . . . . . . . . . 3
Application command stack . . . . . 5
Pcall function . . . . . . . . . . . 5
Synonyms . . . . . . . . . . . . . . 6
Command chaining . . . . . . . . . . 7
Command parameters . . . . . . . . . 9
Ignoring commands . . . . . . . . . 10
Ignoring individual commands . . . . 11
Clearing ced objects . . . . . . . . 11
Configuration files . . . . . . . . 12
Changing default buffer sizes . . . 13
Status display . . . . . . . . . . . 15
Multiple definitions . . . . . . . . 15
User Commands . . . . . . . . . . . 16
Subfunction 0: Enqueue . . . . 16
Subfunction 1: Dequeue . . . . 17
Return registers . . . . . . . 17
Command processor . . . . . . . 17
Problem reporting . . . . . . . . . 18
Copyright and Disclaimer . . . . . . 19
Appendix A: Command summary . . . . 20
Appendix B: Order of Processing . . 22
Appendix C: Limitations . . . . . . 23
Appendix D: User Command Demo . . . 24
1
=== ced 1.0 User's Guide ===
Purpose
-------
Ced (which stands for Command EDitor) provides the following
functions at the DOS prompt, or from within certain applications
programs:
-- Complete command line editing facility.
-- Recall of previously issued commands for re-entry.
-- Command synonyms, which may include "chaining" of a
series of commands.
-- Parameterization of synonym commands.
-- Recall of parameters for previously issued commands.
-- User-settable buffer sizes for all functions.
-- For programmers, a facility to add new "resident"
commands to the DOS shell.
Ced is an evolutionary development of two earlier programs by
another author: DOSEDIT, and RETRIEVE (an IBM copyrighted
product). It performs all of the functions of both programs, and
has a number of enhancements. Both DOSEDIT and RETRIEVE were
written by Jack Gersbach.
System Requirements
-------------------
Ced was written for an IBM PC/XT/AT or compatible machine.
However, it uses no hardware-specific functions, so it will
probably work with any MS-DOS machine.
Ced requires DOS Version 2.00 or later. It increases the size of
resident DOS by about 14K bytes after installation with default
buffer sizes (this can be reduced).
Terminology
-----------
This document will usually refer to "commands" or "DOS commands"
as ced targets; you should take this to mean either (a) actual
DOS commands, or (b) input to ced-compatible programs (for
example, DEBUG commands).
Key names are as follows:
2
=== ced 1.0 User's Guide ===
<Up> The up-arrow key on the numeric keypad.
<Down> The down-arrow key on the numeric keypad.
<Left> The left-arrow key on the numeric keypad.
<Right> The right-arrow key on the numeric keypad.
<Backspace> The large left-arrow key, next to NumLock.
A carat (^) means to press the Ctrl key in conjunction with a
named key; for example, <^End> means "press and hold the Ctrl
key, then press <End>".
Words in CAPS are ced keywords and must be typed exactly as shown
(they need not be capitalized when you use them).
Words in [brackets] are optional elements of a command.
Installation
------------
Installation (in its simplest form) is accomplished by typing
"ced" at the DOS prompt, or including the statement "ced" in your
AUTOEXEC.BAT file. There are optional parameters when installing
ced; these will be covered later.
After ced is installed, everything will appear to be normal, but
you now have many new features when entering DOS commands. The
remainder of this document will describe these features.
Ced is active either at the DOS prompt, or when an application
program requests buffered keyboard input from DOS (DOS function
0AH). There are a few such programs (DEBUG and EDLIN are two);
but the main use of ced is at the DOS prompt.
Once ced has been installed, the command "CED" becomes an
internal DOS command. Thus, when you want to issue ced commands
(as explained below), you will type "CED <command>", but the
program file (CED.COM) need NOT be available on disk. Ced
becomes fully memory resident and is an extension to DOS after
installation. In particular, this means that you should NOT
include a drive or path in issuing CED commands after initial
installation. A command like "C:CED SYN d dir" will reload ced,
which is probably not what you intend.
Command line editor
-------------------
Ced provides a new "editor" for DOS commands. The DOS editing
keys (F3 for copy-to-end-of-line, for example) are no longer
available. Instead, the following keys may be used:
<Home> Cursor to home position (first character).
3
=== ced 1.0 User's Guide ===
<End> Cursor to end position (following last
character displayed).
<Left> Cursor left one character position. This
does not erase any characters, it simply
moves the cursor.
<Right> Cursor right one position.
<^Left> Cursor left one word.
<^Right> Cursor right one word.
<Ins> Enter/exit Insert mode. When Insert is on,
new characters will be inserted at the
current cursor position. When Insert is off,
new characters will type over the character
at the cursor position.
<Del> Delete the character at the cursor position.
<Backspace> Delete the character to the left of the
cursor position (destructive backspace).
<^End> Delete all characters from cursor position to
end of line.
<Esc> Cancel: erase all data and start over.
When you have completed entering and editing the command, press
<Enter> as usual to execute.
DOS command stack
-----------------
Ced keeps a record of each command you enter. You can retrieve
and re-enter these commands by using the <Up> and <Down> keys to
display the old commands, then pressing <Enter> when the desired
command is displayed (the command can be edited, of course).
You can visualize the stored data as a "stack" of commands.
Ced keeps a pointer to somewhere in this stack. The pointer
always points to a location "between" two commands; when you
press <Up>, ced displays the command "above" the pointer, then
moves the pointer up one command. When you press <Down>, ced
displays the command "below" the pointer, then moves the pointer
down one command.
For example, suppose you have entered commands A, B, and C. The
stack will appear as follows:
4
=== ced 1.0 User's Guide ===
+-------------+
| A |
+-------------+
| B |
+-------------+
| C |
+-------------+ <-- pointer
The stack is circular in nature; thus, if the pointer points
"below" the last command in the stack (as it does above), it is
actually between the last command (C) and the first command
(A). In the situation above, pressing <Up> will display command
C and leave the pointer between B and C. Pressing <Down> will
display command A, and leave the pointer between A and B.
When you recall an old command and re-enter it without editing,
the re-entered command is not added to the stack, and the pointer
will drop one level. Suppose, for example, that you press <Up>
twice from the position above (pointer below C): B is displayed,
and the stack looks like this:
+-------------+
| A |
+-------------+ <-- pointer
| B |
+-------------+
| C |
+-------------+
If you now press <Enter> (without editing the command), command B
will be sent to DOS, and the pointer will drop to point between B
and C. From there, <Up> will display B again, and <Down> will
display C. Thus you can "recycle" a series of commands by
pressing <Up> until you see the first command, <Enter> to execute
it, then a series of <Down><Enter> sequences to re-execute the
commands in the original order.
If you retrieve an old command and edit it before execution, the
newly edited command is added to the bottom of the stack, and the
pointer will point just below it.
Ced will not stack any commands of two characters or less (the
theory being that it's easier to retype than to go searching
through the stack).
This is one of those computer gizmos that's easier to use than it
is to explain. Just play with <Up> and <Down>; you'll get the
idea.
5
=== ced 1.0 User's Guide ===
You can remove a command from the stack by displaying it and
pressing <PgDn>, and you can clear the entire stack by pressing
<PgUp>.
The actual number of commands which will be held in the stack is
a function of the length of the commands and the size of the
stack (which can be increased; see below for details).
Application command stack
-------------------------
Ced actually keeps two complete command stacks: one is for DOS
commands, the other for commands entered into compatible appli-
cations programs (DEBUG, et al). Thus, DOS commands will not
appear in the command stack while in DEBUG, and vice versa.
Pcall function
--------------
"Pcall" stands for parameter recall; this is a second way to
quickly retrieve old commands. Pcall simply remembers old
parameters to specific commands. For example, suppose you have
an editor called "edit", and the last time you executed it, you
used "edit c:\util\foo.doc". If you now enter "edit" without any
parameters, ced will assume that you want to edit the same file
and will supply the "c:\util\foo.doc" for you.
You could, of course, scroll back through the command buffer to
find the old command, but it might take a while to find it (and
the command might be missing if it was too long ago).
Because many commands are best used WITHOUT parameter recall
(FORMAT and ERASE are good examples), ced will only use pcall on
commands that you specify. To make a command "pcallable", type
CED PCALL <command>
at the DOS prompt. For example, if you want to make "edit" a
pcall command, type
CED PCALL edit
(Remember that the ced diskette need not be available).
If you wish to issue a command for which pcall is enabled, but
you do not want it to have parameters, add a space after the
command. For example, suppose you have issued a "CED PCALL dir"
command and your last dir was a "dir *.exe". If you now type
"dir", ced will add the "*.exe" automatically. However, if you
type "dir " (note the space), ced will not add the "*.exe", and
you'll get a full directory.
6
=== ced 1.0 User's Guide ===
You may also bypass pcall processing through the use of the
ignore character; see below, under "Ignoring Individual
Commands".
Synonyms
--------
The synonym function allows you to define brief "synonyms" for
frequently used commands. For example, suppose you invoke your
communications package by typing "talk rbbs /c63". Ced allows
you to abbreviate this to a shorter command, say, "bb", by
typing at the DOS prompt:
CED SYN bb talk rbbs /c63
The exact syntax is:
CED SYN <synonym> <command>
The <synonym> is the command abbreviation (which you will type at
the DOS prompt), and <command> is the word or phrase which ced
will substitute when it sees <synonym>. The synonym is always
the first word after the keyword "syn", and <command> is always
all of the remaining words.
For example, "ced syn d dir" allows you to type "d" instead of
"dir". You may add parameters: "d *.exe" becomes equivalent to
"dir *.exe".
Many people define very short synonyms for frequently used
commands:
CED SYN d dir
CED SYN e edit
CED SYN g debug
CED SYN l link
CED SYN rbbs talk rbbs /c63
CED SYN cc1 cc1 -bpe
Note in the last example that you can use a synonym which is
identical to its associated phrase and simply use it to automat-
ically add parameters.
Also note that synonym processing takes place AFTER pcall
processing; thus if you use a command synonym and wish the
command to be "pcallable", use the synonym in the pcall command.
For example:
CED SYN e edit
CED PCALL e (not PCALL edit)
7
=== ced 1.0 User's Guide ===
User program synonyms
---------------------
Because ced "knows" whether it is being used from the DOS prompt
or from an application program such as DEBUG, it is possible to
define separate sets of synonyms for DOS commands and for user
programs. The syntax for a "user synonym" is
CED USERSYN <synonym> <command>
This is identical to the SYN command except for the new keyword
USERSYN. For example, if you need to frequently type the DEBUG
command "d ds:1010 1200", you might use
CED USERSYN d1 d es:1010 1200
(Remember that DEBUG is a ced-compatible program; thus you can
type ced commands at the DEBUG prompt.) Then you could simply
type "d1" to dump memory from the specified address. Note
that a "d1" USERSYN is separate from a "d1" SYN; at the DOS
prompt you'd get the SYN, in DEBUG or EDLIN you'd get the
USERSYN.
Command chaining
----------------
The command chaining feature allows you to place more than one
command in a SYN or USERSYN. These commands would be passed to
DOS or to the user program one at a time, as input is requested.
Suppose, for example, that in order to run your communications
package, you always type:
cd \talk
talk cis /c63
cd \
You could put this sequence into one synonym by typing
CED SYN cis cd \talk^talk cis /c63^cd \
The ^ character serves as a command separator. When you type CIS
at the prompt, ced will output everything up to the ^ (in this
case, "cd \talk") and then simulate an <Enter>. The next time
DOS requests input, it will get "talk cis /c63<Enter>", and so
on.
Note that ced will not pass DOS-chained commands to user
programs; thus, in
8
=== ced 1.0 User's Guide ===
CED SYN bug cd \util^debug^cd \
DEBUG would not see the trailing "cd \", which would still be
held up until you return to the DOS prompt.
The first of the chained commands (e.g., the first 'cd \' above)
cannot itself be a synonym, but the remaining commands can. That
is, if 'f' and 'g' are synonyms, the command
CED SYN h dir^f^g
will work as you expect. Be careful, though. A command like
CED syn f dir^f
will put the computer into a loop from which there is no retreat.
If one of the chained commands is a synonym which itself defines
more chain commands, the unused portions of the first chain will
be lost. If, for example, you have defined:
CED SYN f a^b^c
CED SYN b x^y
and you then execute "f", the commands actually executed will be
a, x, and y. Command c will be not be executed.
You may alter the chain character (command separator) via the ced
command
CED CHAINCH <char>
So, for example, "CED CHAINCH &" would replace ^ with & as the
command separator. The chain character can, but probably should
not, be a control character. If you are typing the command
directly into ced, you can just type the control character:
CED CHAINCH <Ctrl-A>
However, if you are setting the chain character via configuration
files (below), it may not be possible to type in the control
character directly. For this reason, you can also specify a
control character by typing the carat (^) and a letter key.
Thus, if you wanted to use ^Y as the chain character, you
would use '^' and 'Y':
CED CHAINCH ^Y
Certain control characters should not be used as for this
purpose, because they are used for other functions by DOS; among
these are ^C (cancel), ^G (bell), ^H (backspace), ^I (tab),
9
=== ced 1.0 User's Guide ===
^L (linefeed), ^M (carriage return), ^P (printer on), and ^S
(stop).
The use of control characters as described has more meaningful
use in setting the "ignore" and "status request" characters
(below).
Command parameters
------------------
This section describes how synonyms and command chaining interact
with command line parameters.
The simplest case is a single word synonym like
CED SYN d dir
which specifies no special parameter handling. In this case, any
command line parameters are simply tacked on after the synonym
substitution: "d *.exe /w" becomes "dir *.exe /w".
If the synonym itself contains parameters:
CED SYN dw dir /w
a similar situation holds. For example, "dw *.asm" becomes "dir
/w *.asm". You might think of these simple nonchained synonyms
as just substitutions: when ced sees the synonym, it will simply
substitute the replacement text, leaving the rest of the command
line alone.
This simple substitution, however, means that your command line
parameters must always be the last text of the synonym. There
would be no way, for example, to define a synonym that would
obtain a directory of <name>.exe, where <name> is some filename
entered on the command line and ".exe" is part of the synonym.
That is, it would not be possible to define a synonym "d" such
that the command
d foo
would result in a "dir foo.exe" command.
However, ced does provide a way to substitute parameters into the
middle of a synonym. Ced recognizes the "%n" dummy parameter
format used by DOS batch files. %1 represents the first command
line parameter, %2 is the second, and so on, up to %9. Refer to
your DOS documentation (batch file section) if this is unclear.
Thus, a synonym which would provide the example function is:
10
=== ced 1.0 User's Guide ===
CED SYN d dir %1.exe
When "d foo" is executed, "foo" (the first command line
parameter) is substituted for the %1, resulting in the desired
command "dir foo.exe".
When a synonym contains chained commands, all parameter
substitution is performed at one time, before the chain is
started. Thus,
CED SYN f a %1^b %2^c %3
when executed "f one two three" will result in three commands:
a one
b two
c three
If a chain-command synonym contains no dummy parameters (no %'s)
the command line parameters will be appended to the end of the
chain, i.e., as parameters to the last command. So,
CED SYN f a^b^c
when executed "f foo" will result in the three commands:
a
b
c foo
Ignoring commands
-----------------
There may be certain commands that you do not want ced to
process; for example, you might not want the ERASE command
stacked. To instruct ced to ignore a command, use the ced
command
CED IGNORE <command>
For example:
CED IGNORE erase
When a command is set to IGNORE, ced will not place it in the
command stack, check for aliases, or perform any pcall processing
(even if you have set PCALL for that command).
11
=== ced 1.0 User's Guide ===
Ignoring individual commands
----------------------------
You may sometimes want ced to ignore processing of a specific
command. For example, you may have "dir" defined as a synonym
for an external program which will display a sorted directory,
but on occasion want to display a standard DOS directory. To
force ced to suspend all processing of a command, precede it with
^N (Ctrl-N). If the first character of input is ^N, ced will
not stack the command, check for aliases, or perform any pcall
processing (just as if it were IGNOREd). The Ctrl-N, of course,
is not passed to DOS or to the application program. For example:
^Ndir
If you find ^N inconvenient, you can change the ignore character
to a different character by using the IGNORECH command:
CED IGNORECH ^T
CED IGNORECH !
See the section on command chaining (above) for more information
on how to enter control characters in this command.
Clearing ced objects
--------------------
From time to time it may be useful to clear a ced "object": a
pcall command, a synonym, or an ignore command. The CLEAR
command allows you to do this. The formal syntax is:
CED CLEAR <function> [[FROM] <name>]
This looks more complex than it is. The <function> is one of
SYN, USERSYN, PCALL, and IGNORE. Since the [[FROM] <name>] is
optional, the simplest form of the clear command is exemplified
by:
CED CLEAR SYN
which will clear all synonyms. Similarly,
CED CLEAR PCALL
clears all pcall commands.
You may clear an individual item by including its name. For
example:
CED CLEAR USERSYN foo
12
=== ced 1.0 User's Guide ===
clears the user synonym "foo", leaving all others synonyms
undisturbed.
Finally, you can clear all items FROM a specified item through
the end of the list with the FROM option. For example:
CED CLEAR USERSYN FROM foo
would clear the user synonym "foo" and all synonyms listed after
"foo". This command is particularly useful if you have loaded a
temporary set of synonyms for some special purpose. Suppose, for
example, that you have a set of synonyms already in memory, then
you load an additional set to be used temporarily. When you are
done, the command
CED CLEAR SYN FROM foo
would delete all of the "temporary" synonyms, assuming that the
first of these was "foo".
Note that SYN and USERSYN objects share storage. Thus, a
CLEAR SYN FROM <item> or CLEAR USERSYN FROM <item> will clear all
synonyms (of either type) FROM the named item. Similarly, CLEAR
SYN and CLEAR USERSYN are functionally identical: all synonyms of
either type will be cleared.
Configuration files
-------------------
Obviously it would be inconvenient to have to type in all of
these commands every time you use your computer. However, you
may put any ced command into a special ced configuration file,
and have them loaded all at once.
The configuration file is simply an ASCII text file (created by
your text editor, EDLIN, or word processor in nondocument mode)
which contains a series of ced commands. Just leave out the
keyword "CED", but include the rest of the command:
Rem Remarks are OK if preceded by "REM"
Rem
Rem Set chain char to '&'
Chainch &
Rem Set ignore char to '!'
Ignorech !
Rem Set a few synonyms
Syn d dir
Syn e edit
Syn cis cd \talk & talk cis & cd \
Usersyn dd d ds:1017 L40
Rem And a few pcall commands
13
=== ced 1.0 User's Guide ===
Pcall e
Pcall debug
Rem Ignore all DEL, ERASE, and FORMAT commands
Ignore erase
Ignore format
Ignore del
To read in your file, use the CED -f command line switch:
CED -F<filename>
For example, if your configuration file is call CED.CFG, you'd
use
CED -Fced.cfg
If you load new configuration files during one computer session,
the PCALL, SYN, USERSYN, and IGNORE commands are added to those
already stored, without regard to duplication (see "Multiple
definitions" below).
Note that if you have several commands that you want to enter
into ced (but don't have them in a file), you can use
CED -Fcon
(which specifies CON: as the configuration file name) and then
type a series of ced commands from the keyboard. Type ^Z when
you are done.
Changing default buffer sizes
-----------------------------
Ced maintains six separate internal buffers (regions of memory
where data is stored). Each buffer is initially set to a default
size. The buffers and their default sizes are:
1. DOS command stack (2048 bytes)
2. Application program command stack (1024)
3. Synonym list (2048)
4. Pcall list (1024)
5. Ignore command list (1024)
6. User command list (described below) (1024)
You may make these buffers larger or smaller by including a list
of buffer sizes the FIRST time you load ced during a session
(i.e., when you turn on the computer, or after a Ctrl-Alt-Del
reboot). Use a -B switch as the FIRST ced command:
CED -Bn1,n2,n3,n4,n5,n6
14
=== ced 1.0 User's Guide ===
where n1 is the desired size for buffer 1 (DOS command stack), n2
is the size for buffer 2 (App program command stack), etc. You
need not specify all sizes, but if you skip one or more sizes
(telling ced to use the default) you must include the separating
commas. Examples:
CED -B1000,2000,3000,4000,5000,6000 (Set all sizes)
CED -B1000,,3000 (Set sizes 1 and 3)
CED -B,,,,,6000 (Set size 6 only)
You cannot set any individual size less than 128 bytes, and the
total of all sizes must be not exceed 52K (53248) bytes.
Remember that the -B command must be the FIRST command used the
FIRST time you run ced during each session. It is not valid any
other time. If you wish to set sizes and read a configuration
file during autoexec, the syntax would be:
CED -Bn1,n2,n3,n4,n5,n6 -F<filename>
For your general information, here is what is stored in each of
the buffers, and what happens when it fills:
1. DOS Command stack: all non-ignored commands of 3 or more
characters entered at the DOS prompt. The command is stored
before alias and pcall processing. Each stored command requires
one byte more than the length of the command. When the buffer
fills, the oldest command is deleted.
2. Application program command stack: same as above, except
commands entered at participating program prompts are stored
here.
3. Synonym list: the full list of synonyms (both DOS and user
synonyms) plus their meanings. Each entry requires the combined
length of the synonym and its associated command plus three
bytes. When the synonym list fills, no new synonyms will be
accepted unless a CLEAR is performed first.
4. Pcall command list: the list of all pcall commands plus the
most recent parameter list for each. Each entry requires the
combined length of the command and its parameters (including
leading separators) plus two bytes. If the buffer is full when a
"CED PCALL" command is entered, the new pcall command will not be
accepted. If the buffer is full when a pcallable command is
entered, its parameters will not be remembered.
5. Ignore command list: the list of all IGNORE commands. Each
entry requires the command length plus one byte. If the buffer
is full when a new "CED IGNORE" command is entered, the new
command will be rejected.
15
=== ced 1.0 User's Guide ===
6. User command list: the list of all user-installed commands.
Requires the command length plus six bytes of storage for each.
New commands will be rejected if the buffer is full. Ced itself
uses ten bytes of this buffer.
Status display
--------------
You may obtain a partial display of ced status any time CED is
active (i.e., at the DOS prompt or in a compatible program
awaiting input). Do this by hitting ^T (Ctrl-T). Ced will first
display all synonyms (preceded by [S] for SYN or [U] for
USERSYN), then a list of all buffers. For each buffer ced will
show the total bytes allocated and the number of bytes free.
When the display is complete, ced will redisplay any partial
input that you typed before ^T, and you may continue data entry.
If ^T is not convenient, you can change the status request
character by using the ced command
CED STATCH <character>
as in "CED STATCH ^A" or "CED STATCH %". See the section on
command chaining for more information on using control characters
in this command.
Multiple definitions
--------------------
It is possible to duplicate a definition within one of the ced
lists (SYN, USERSYN, PCALL, IGNORE). For example, you may create
more than one synonym for "d". In the event of multiple
definitions, ced will always use the newest.
Suppose, for example, that you have "d" defined as a SYN for
"dir". If you subsequently issue the command "CED SYN d debug",
you will have two synonyms for "d". When you enter "d", ced will
use the latest definition: "debug". If you then issue a "CLEAR
SYN d", ced will again use the latest definition and clear the
"debug" synonym, at which point the "dir" definition again
becomes effective.
Multiple definitions have no real meaning for PCALL and IGNORE,
but they are supported nonetheless.
16
=== ced 1.0 User's Guide ===
User Commands
-------------
This section describes how to add new resident commands to DOS
using ced. It is an advanced topic, and is intended for
programmers only; you don't need to read this section to use ced.
Ced provides a means to enqueue new DOS commands, that is, to add
internal commands to DOS. Once enqueued, ced will call a routine
that you specify whenever the user types the new command (at
the DOS prompt, or in a "participating" program).
Access to ced service is provided via a bogus DOS function,
0FFH. This function behaves as a normal DOS function; that is,
you must set up the registers as needed by the call, place a 0FFH
in register AH, and execute an INT 21H. The two subfunctions are
described below; the subfunction code is placed in register
AL.
SUBFUNCTION 0: ENQUEUE
This subfunction allows you to enqueue a new command. Input
register use is as follows:
AH = 0FFH (ced service)
AL = 0 (ENQUEUE)
BL = MODE
This is a bit flag which tells ced when to call your
routine. You have the option of being called if your
command is typed at the DOS prompt, at a user program
prompt, or both. Bit 0, if set, specifies that you are
to be called at the DOS prompt; Bit 1, if set,
specifies that you are to be called at a user program
prompt.
DS:SI = command name
This is a dword pointer to your command (i.e., you are
to be called when the user types this string). The
command must be from one to eight characters,
terminated by a carriage return. Ced is not case
sensitive.
ES:DI = command processor entry point
This is a dword pointer to the routine which is to be
executed when the new command is entered.
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=== ced 1.0 User's Guide ===
SUBFUNCTION 1: DEQUEUE
This subfunction allows you to dequeue a user command; after a
command has been dequeued, ced will no longer call you if the
user types your command. Input register use is:
AH = 0FFH (ced service)
AL = 1 (DEQUEUE)
DS:SI = command name
A dword pointer to the name of the command to be
dequeued (i.e., the same DS:SI as was used to enqueue
the command).
RETURN REGISTERS
On return from ced service (DOS function 0FFH), all registers are
preserved except AX. The carry flag, if set, indicates that an
error occurred; AX has the error code, which will be one of:
1: Invalid function. At present, only subfunctions 0
and 1 are supported. Subfunction 2 is reserved.
2: Command not found (DEQUEUE only).
8: Insufficient memory (ENQUEUE only).
13: Invalid data. (ENQUEUE only; bad MODE flag, or invalid
command length).
NOTE: In current versions of DOS, AH returns 0FFH if function
0FFH is requested and ced is not installed. You may use the
reserved subfunction (2), at your own risk, to test for ced
installation. If AH returns any value other than 0FFH, ced is
probably installed.
COMMAND PROCESSOR
Your command processor is entered via a far call from ced. Entry
registers are as follows:
BL = MODE
This is the same bit flag as is used in the ENQUEUE
subfunction. You may use it to test "where you are".
CL = MAXLEN
This is the maximum allowed length of the user input
string (i.e., the value of byte 0 of the DOS function
0AH input buffer) less one.
18
=== ced 1.0 User's Guide ===
DS:DX = Command tail pointer
This is a dword pointer to the command tail of the
user's input. For example, if your command is "hello"
and the user types "hello sam", DS:DX will point to the
space after "hello".
DS:DI = Command pointer
This is a dword pointer to the first byte of the actual
user input.
Note that DS:DI and DS:DX point to buffer space within ced, not
to the actual DOS function 0AH input buffer. There are no
length attribute bytes preceding the buffer; DS:SI points to the
first byte of the buffer, not the third. Ced will copy the final
buffer, after all processing, to the actual input buffer.
You may manipulate the buffer to your heart's content. It is 255
characters long, but ced will truncate the string if necessary
(if the final command is longer than the maximum allowed by the
function 0AH request). In particular, note two things about the
ced buffer:
1. The string MUST be terminated by a carriage return
ASCII 13).
2. If you null out the buffer (by putting a carriage
return in relative byte 0) ced will return a null
string to DOS or the user program. This is probably
what you will want to do.
There are few restrictions on what you can do within your service
routine. You may request other DOS service (but you may NOT
request more buffered input via function 0AH!!), and you need not
preserve any registers except SS:SP. The stack in effect on
entry will have about 200 bytes free; switch to a larger internal
stack if necessary.
Return to ced via a far RET.
Appendix D contains a sample MASM program to enqueue a trivial
command.
Problem reporting
-----------------
If you find any problems with ced, please report them to me,
preferably at CompuServe ID 76703,2002. Before reporting
problems, however, please take the following steps:
1. Reread the documentation!
19
=== ced 1.0 User's Guide ===
2. Install ced in a "clean" environment, i.e., without any
other resident utilities. Temporarily rename your
AUTOEXEC.BAT and CONFIG.SYS files to other names; reboot,
reinstall ced, and test. If it works correctly, there is a
conflict with some other program. Isolate the conflict by
reinstalling your other programs one by one and by varying
the load order. If you locate the conflict, let me know
about it. I cannot guarantee that the conflict will be
resolved, but I will make an attempt when time permits.
It would not be necessary to rename CONFIG.SYS if it only
contains FILE, BUFFER, COUNTRY, FCBS, and ANSI.SYS
statements.
If the problem persists, please report the problem as accurately
and completely as possible. Include the ced version number
(obtained by the command CED VER), and a listing of your
CONFIG.SYS and AUTOEXEC.BAT files if you think that might have
some bearing.
Copyright and Disclaimer
------------------------
Ced is hereby placed in the public domain. Both ced and this
documentation are, however, copyrighted by the author. Ced is
intended for your private, noncommercial use only. You may make
copies of the ced program and documentation files for your own
use, and you may copy the files for others. You may not,
however, charge for such copies, or in any other way sell the
program or otherwise attempt to make money from it or any
modified version of it.
However, recognized user's groups are hereby authorized to charge
an amount not more than $6.00 for materials, postage, etc.
I do not warrant that the documentation is accurate, or that the
program operates as designed. I will not be liable for any
damages of any kind sustained through the use of the program. By
using the program, you agree to this.
IBM is a registered trademark of International Business Machines
Corporation. MS-DOS is a trademark of Microsoft Corporation.
Both ced and this document are:
Copyright (c) 1985 by
Christopher J. Dunford
10057-2 Windstream Drive
Columbia, Maryland 21044
CompuServe ID 76703,2002
20
=== ced 1.0 User's Guide ===
Appendix A: Command summary
---------------------------
The following is a complete summary of all ced commands. These
commands may be included in a ced configuration file (with the
exception of -F and -B), or they may be typed in directly by
prefixing them with "CED ".
-Bn1,n2,n3,n4,n5,n6 Sets the sizes of the six internal
buffers. Valid ONLY as first command
when installing ced after boot or
reboot.
-F<Filename> Loads a ced configuration file. Not a
valid command within a config file.
SYN <synonym> <command> Defines a synonym. The first word is
the synonym, all remaining words are
substituted for the synonym.
USERSYN <synonym> <command> Defines a user synonym. Identical
to SYN, except that the synonym is
available within user programs rather
than at the DOS prompt.
PCALL <command> Defines a command subject to pcall
processing.
IGNORE <command> Defines a command to be ignored--ced
will not perform any processing on this
command at all.
CHAINCH <char> Defines the command chaining character,
which is the character used to separate
commands in a multi-command synonym.
IGNORECH <char> Defines the keyboard-ignore character;
when this character is typed as the
first character of keyboard input, ced
will perform no further processing on
it.
STATCH <char> Defines the status request character.
When you type this character while ced
is active, ced will display its status.
CLEAR <function> [[FROM] <name>] Clears all or part of a
list of ced objects. <function> is one
of SYN, USERSYN, PCALL, or IGNORE.
Without arguments, clears all of the
specified list. With a <name>, clears
that item only. With a FROM <name>,
21
=== ced 1.0 User's Guide ===
clears that item and all subsequent
items.
VER Display ced version number and copyright
notice.
Commands may be abbreviated as follows:
USERSYN USYN
PCALL PC
IGNORE IG
CHAINCH CC
IGNORECH IC
STATCH SC
CLEAR CL
Note, however, that the arguments to CLEAR may NOT be
abbreviated; CLEAR USYN or CLEAR PC are not valid.
22
=== ced 1.0 User's Guide ===
Appendix B: Order of Processing
-------------------------------
Ced performs its basic processing in the following order:
1. Obtain input. If there is a chained command pending, obtain
input from the chain; otherwise from keyboard.
2. Check for "ignore". If command is an "ignore" command or if
the first character of input is the ignore character, suspend all
further processing.
3. Stack the command (if longer than two characters) in the
appropriate command stack.
4. Perform pcall (parameter recall) processing and store the
result for pcall processing next time the same command is
entered.
5. Perform synonym processing and parameter substitution. If the
synonym contains chained commands, set up for chaining of
subsequent input requests.
6. Examine the resulting command and see if it's a user-installed
command or a CED command. If so, call CED or user command
processor.
23
=== ced 1.0 User's Guide ===
Appendix C: Limitations
-----------------------
There is a limit of 255 characters on any input line from a ced
configuration file. DOS will limit you to 127 characters at the
DOS prompt.
For PCALL, SYN, USERSYN, and IGNORE to be effective, their
commands must begin in the first column of input and must be
separated from any parameters by one of the following characters:
; , < > | = + [ ] / <Tab> <Space>
Thus, if you have "cd" defined for pcall processing, "cd\" will
not work correctly. However, "cd \" will be OK. Similarly, if
you have a synonym "d" for "debug", the command "c:\util\d" will
not work, nor will " d" (note leading space).
Programs which allow you to execute DOS commands or other
programs as subtasks generally do not use DOS function 0AH to
input the name of the subtask or command; thus, ced is not
active, and synonyms are usually not effective.
24
=== ced 1.0 User's Guide ===
Appendix D: User Command Demo
-----------------------------
Comment *
userdemo.com - demo of ced user command enqueuing
Assembly: (M)ASM userdemo;
LINK userdemo; (ignore NO STACK message)
EXE2BIN userdemo userdemo.com
Use: Just type 'userdemo'. You now have
a new DOS command, "hello"
Author: CJDunford
05/28/85
*
CED equ 0FFH ; Special "DOS" fn for CED service
ENQUEUE equ 0 ; Subfunction: enqueue
DEQUEUE equ 1 ; Subfunction: dequeue
DOS equ 1 ; Cmd to be active at DOS prompt
USER equ 2 ; Cmd to be active at user prompt
CR equ 13
LF equ 10
code segment
assume cs:code,ds:code
org 100H
main proc far
jmp Install ; Go to installation
; -----------------------------------------------------
; This is the command processor. It will be called
; whenever the user types "hello" at the DOS prompt.
; The routine simply prints the string "Hi there, ace".
;
; On entry:
; BL: mode flag
; 1 = at DOS prompt
; 2 = at user program prompt
; CL: max length of input
; DS:SI => user command
; DS:DX => user command tail
;
; Remember to null out the user string so that
; it is not passed on to DOS, then exit via a far
25
=== ced 1.0 User's Guide ===
; return to ced. Not necessary to preserve any
; registers.
; ------------------------------------------------------
Hello proc far ; Must be a far procedure
mov byte ptr [si],CR ; Null out the user's input
mov ax,cs ; Set up local addressing
mov ds,ax
mov dx,offset HiThere$ ; Display our message
mov ah,9
int 21H
ret ; No need to restore any regs
Hello endp
HiThere$ db 'Hi there, ace',CR,LF,'$' ; Message to be displayed
; -----------------------------------------------
; This is the installation routine. It sets up
; the regs for a call to the ced command enqueing
; service, enqueues the command, and terminates,
; leaving the command service routine resident
; ------------------------------------------------
Install:
mov ah,CED ; CED service request
mov al,ENQUEUE ; Enqueue a new command
mov bl,DOS ; To be active at DOS prompt
mov si,offset Hello$ ; DS:SI => command ("Hello")
mov di,offset Hello ; ES:DI => service routine
int 21H ; Enqueue new command
jnc OK ; No carry, no error
mov dx,offset Error$ ; Only 1 error possible here
mov ah,9 ; Print string
int 21H
int 20H ; Return to DOS
OK:
mov dx,offset Install ; OK: terminate/resident
int 27H
main endp
Hello$ db 'hello',CR ; New command
Error$ db 'ced user command list full',CR,LF,'$'
code ends
end main
