*DDTF5.DOC
*2/22/88
*
*			    DDTF5 Documentation
*       (C) Copyright 1981, 1985, 1986, 1988 by LOGIC ASSOCIATES, Chicago
*
*         A "find-string" function for use during DDT, SID, etc.
*
*	Permission is hereby granted only for non-commercial copying
*	and distribution of DDTF5.COM, DDTF5.ASM, and DDTF5.DOC.
*
*
*
*>>>>> Essential:  Read "ASSEMBLY INSTRUCTIONS" near the end of <<<<<
*>>>>> this document before attempting to assemble DDTF5.ASM.   <<<<<
*
*********************************************************************
*
*			   VERSION HISTORY
*
*	Version 5 has a stronger self-protection algorithm, to protect
*	against removal by other utilities that may already be resident
*	below the CCP.  (Some such utilities would remove DDTF between
*	the time it invoked the debugger and the time the debugger was 
*	loaded.)
*
*	Version 4 has been given a more flexible procedure for finding
*	the ccp, in order to be compatible with more systems.
*
*	Version 3 introduced "wild-card" searches.
*
*	Unlike version 1, versions 2 and later use no restart locations.
*
*
*********************************************************************
*
*			   INSTRUCTIONS
*
*
*	This program searches main memory (RAM) for all occurrences of
*	any string.
*
*	DDTF5 is invoked in the same fashion that DDT, SID, or any other
*	debugger is invoked.  You can type "DDTF5 PROGNAME.COM" to load
*	a program called PROGNAME.COM into memory under your debugger and
*	DDTF5.  Or you can simply type "DDTF5" to load your debugger and
*	DDTF5 by themselves.
*
*	Once DDTF5 and your debugger have been loaded, you may set up
*	any desired search-string.  Insert it into memory starting at
*	location 5dh.
*
*	[]  The string may be installed via the I, A, and/or S commands
*	    of your debugger.
*
*	[]  The string should start and end with the same character, one
*	    not used elsewhere in the string.  Example: "/find this/".
*
*	[]  A "wild card" position in the string is represented by a
*	    "?" (3fh).  For instance, "/r??t/" will be matched by "root",
*	    "rant", or "r @t".  (This holds true even when searching for a
*	    string of machine code.)
*
*	A listing of all occurrences of the desired string can now
*	be found and displayed by typing control-F.  To repeat the
*	search, type control-F again, as many times as desired.
*
*	Each occurrence is represented by a one-line, ddt-style dump.
*	The sought-for string will appear in the middle of the line.
*
*
*	Notes:	[]  A summary of the above instructions will be displayed
*		    by DDTF5 anytime you type control-A (for "Assistance").
*
*
*		[]  If the search turns up negative, check your model for--
*
*			1)  A missing prefix or suffix:  (E.g., "/find this".)
*
*			2)  A suffix or prefix that also appears inside
*			    the string.  (E.g., "/find/this/".)
*
*
*
*********************************************************************
*
*			EXAMPLES
*
*..................................................................
*
*
*	Example 1:  Find all instances of "disk".
*
*	Procedure:	-i/disk/<cr>	  where "<cr>" is the RETURN key.
*			-^f<cr>
*
*
*
*..................................................................
*
*
*	Example 2:  Find all copies of "JMP CDAB".
*
*	Procedure:	-a5d<cr>
*			005D nop<cr>
*			005E jmp cdab<cr>
*			0061 nop<cr>
*			0062<cr>
*			-^f<cr>
*
*
*
*..................................................................
*
*
*	Example 3:  Find all instances of hex 005638.
*
*	Procedure:	-s5d<cr>
*			005D ff<cr>
*			005E 00<cr>
*			005F 56<cr>
*			0060 38<cr>
*			0061 ff<cr>
*			0062 .<cr>
*			-^f<cr>
*
*
*..................................................................
*
*
*	Example 4:  Print a fascinating display.  (Be sure to try this.)
*
*	Procedure:	-i//<cr>
*			-^f<cr>
*
*
*
*********************************************************************
*
*		     INTERFACING AND CUSTOMIZING
*
*
*   []  This module relocates itself under the ccp, prints a signon
*	message, then invokes your debugger.  After loading, this module
*	occupies .5K, but since it protects both itself and the CCP, this
*	module entails a total overhead of 2.5K.
*
*
*   []  If you are debugging a program under DDTF5, DDTF5 will not disturb
*	your program's registers.  But DDTF5 does use about five levels
*	of your program's stack, so be sure there is enough stack space.
*
*
*   []  Several variables in the source code can be changed if need be:
*
*	Variable	Default value	Meaning
*	--------	-------------	-------
*
*	BDOS7		11h		Value of the byte at BDOS+7 in
*					your system.  (Standard is 11h).
*
*	DBG		"DDT     "	Name of your debugger.  (Must be
*					exactly 8 characters long.)
*
*	SRCHSTR		0		Start of block to be searched.
*
*	SRCHLEN		0ffffh		Length of block to be searched.
*
*	BOOT		0		Warmboot entry point in your system.
*
*	LINELEN		16		Number of chars displayed in
*					hex and ascii per line.  (16
*					fits an 80-column display.)
*
*
*
*********************************************************************
*
*		IMPORTANT:  ASSEMBLY INSTRUCTIONS
*
*	Note:  As distributed, this source code can be assembled
*	only by LASM.COM or LINKASM.COM, Ward Christensen's public
*	domain assemblers.  LINKASM is available as CPMUG 36.11 and 
*	36.12; LASM.COM is available on many RCPM downloading systems.
*	(LASM is LINKASM enhanced to display the name of each source
*	file as it is being assembled.)
*
*	LASM's special feature is allowing separate source files to
*	treated as one file, if each previous file chains in the next
*	via a LINK statement (eg., "LINK NEXT.ASM").  If linked to
*	itself, a file can simulate two source copies of itself (or of
*	some of its routines).  This provides a convenient method for
*	creating a relocatable program without using a relocating
*	assembler.  DDTF5.ASM uses this technique.
*
*	1)  If LASM is available, DDTF5.ASM will assemble without
*	modification.
*
*	However, there is one proviso:  if you change the name of the
*	source file from DDTF5.ASM to something else, you must also change
*	the "LINK DDTF5.ASM" instruction at the end of the source file
*	to reflect the new name.
*
*	2)  If LASM is not available, the following "double up"
*	procedure will allow you to use DDTF5.ASM with any assembler.
*
*		a)  PIP DF.ASM=DDTF5.ASM
*
*		b)  Using any editor, erase these lines from the end
*		    of the new DF.ASM:
*
*			IF	NOT COPY1
*			LINK	DDTF5
*			ENDIF
*
*		c)  PIP DF.ASM=DF.ASM,DF.ASM
*
*		d)  Use ASM.COM to assemble DF.ASM instead of DDTF5.ASM.
*
*		e)  Use LOAD.COM to convert DF.HEX into DF.COM.
*
*	The resulting DF.COM is equivalent to DDTF5.COM.
*
*
*
*********************************************************************
*
*						4/15/86
*
*	Dear Colleague,
*	
*	Using DDTF5 has saved us much time and frustration, and we're
*	sure it will do the same for you.  We have designed it to be
*	both useful and easy to use--as well as free.
*
*	If you are also looking for commercial software, we invite you
*	to write us for our catalog and copies of published reviews.
*	Our software packages include--
*
*	[]  DISKGUISE, a utility that reassigns disk drive names,
*		       converts user areas into "disk drives", supports
*		       255 user areas, autosearches .OVR files, and more.
*	[]  VERSBASE, a real-time manager of version numbers in filenames.
*	[]  MEGABACK, a crash-proof utility for backing up hard disks.
*	[]  TUTORI/O, a single-key, software probe for exploring BDOS
*		      file operations.  ("Breathtaking", DDJ, October,
*		      1983, p. 112.)
*	[]  SUPERMIT, a BASIC-like language for creating batch jobs.
*		      (Also available free of charge on many RCP/Ms.)
*
*	Thank you for your interest, and we hope you enjoy DDTF5.
*
*					Sincerely,
*						Roy J. Lipscomb
*
* LOGIC ASSOCIATES, 1433 W. Thome, Chicago, IL 60660, (312) 274-0531
*
**********************************************************************
 						(end of documentation)