DOCUMENTATION FOR TD.COM (November 16, 1985 verson)




TD.COM is a Dynamic Debugging Tool like DDT that uses TDL/CDL 
type mnemonics for the Z-80.  Most of the commands are identical 
or at least very similar to those of DDT and can be found in the 
documentation that comes with CP/M, by Digital Research.  A short 
list of the documented and un-documented DDT commands are 
included here along with the new commands of TD.

    Command:	Action:

	A	Enter assembly language mnemonics and operands
	B	n/a
	C	n/a
	D	Display memory in Hexidecimal and ASCII
	E	End/Close file
	F	Fill memory with constant
	G	Begin execution with optional breakpoints 
	H	Hex math functions
	I	Setup standard input file control block
	J	n/a
	K	n/a
	L	List memory using assembler mnemonics
	M	Move a block of memory from source to destination
	N	n/a
	O	Open a file
	P	Parse for matching hex word
	Q	n/a
	R	Read program for testing
	S	Substitute memory values
	T	Trace program execution
	U	Un-trace program execution
	V	Verify identical memory blocks
	W	Write to file
	X	eXamine CPU registers or flags
	Y	n/a
	Z	n/a
EXAMPLES:	(Note: user supplied carriage return shown as [RETURN]
		cursor shown as '#', addresses are shown between
		parenthisis)

 A	Enter assembly language mnemonics and operands
	GENERAL FORM:	A(start)

 -A100 [RETURN]
 0100  LXI H,0 [RETURN]
 0103  DAD SP [RETURN]
 0104  LXI SP,1400 [RETURN]
 0107  SHLD 13D0 [RETURN]
 010A  [RETURN]
 -

 B	n/a
 C	n/a

 D	Display memory in Hexidecimal and ASCII
	GENERAL FORM:	D(start),(finish)

	If the finish is not supplied 12 line will be 
	displayed.  If the start is not displayed, the 
	address after the previous 'D' command ended will 
	be used, or failing that 0100h.

 -D100 [RETURN]
 0100 21 00 00 39 31 0C 07 E5 21 5C 00 11 C2 02 7E 12 !..91...!\.... .
 0110 23 13 7E FE 20 CA 28 01 0E 08 CD 96 02 21 65 00 #. . .<.).....e.
 ...
 ...
 01B0 01 FE 3F CA 65 01 23 7E FE 21 DA 65 01 2A 0E 07 ..?.e.# ~.!.e*..
 -#

 E	End/Close file
	GENERAL FORM:	E(optional run address) [RETURN]

 F	Fill memory with constant
	GENERAL FORMS:	F(start),(finish),constant [RETURN]
			F(address),byte [RETURN]
			F(address) [RETURN]

 -F100,100,21 [RETURN]	Fill 0100 with 21H
 -F101,102,0 [RETURN]	Fill 0101 thru 0102 with zeros
 -FC500,FFFF,0 [RETURN] This will usually wipe out CP/M
 -F100,C3		Fill address 100H with 0C3H
 -F100			Same as S option below


 G	Begin execution with optional breakpoints 
	GENERAL FORM:	G(start),(finish) [RETURN]

 -G100,112 [RETURN] 	Executes code starting at 0100h and keeps
 -#			executing code until the program counter
			is 0112H
 H	Hex math functons
	GENERAL FORM:	H(number),(number)

 -H100,200 [RETURN]
 +   = 0300		Sum of two numbers
 -   = FF00		First number minus second number
 *   = 0000		First number times second number
 /   = 0000		First number divide by second number
 MOD = 0100		Remainder from dividing first number by second
 AND = 0000		Bit by bit AND First number with second number
 OR  = 0300		Bit by bit OR'd
 XOR = 0300		Bit by bit Exclusive OR'd

 -#

 I	Setup standard input file control block
	GENERAL FORM:	Ifilename.typ [RETURN] 

 J	n/a
 K	n/a

 L	List memory using assembler mnemonics
	GENERAL FORM:	L(start),(finish)

	Works similar to 'D' command above

 -L100
   0100  LXI  H,0000
   0103  DAD  SP
   0104  LXI  SP,070C
   0107  PUSH H
 -#

 M	Move a block of memory from source to destination
	GENERAL FORM:	M(start),(finish),(destination) [RETURN]

 -MC500,FF00,900 [RETURN]	Copies memory starting at 0C500H thru
 -#				0FF00H to 0900H

 N	n/a

 O	Open a file
	GENERAL FORM:	Ofilename.typ [RETURN]

 P	Parse for matching hex word
	P(start),(finish),(word)

-P100,200,0A0D	Search from 0100h thru 0200 for occurrance of 0A0D
0103		Two occurrences were found, one beginning at 0103h
013A		and one beginning at 013Ah
-#		NOTE: 	The two bytes are searched in reverse order
			in this case the debugger is actually looking
			for a carriage return and line feed (0DH 0AH)

 Q	n/a
 R	Read program for testing
	GENERAL FORM:	R(optional bias) [RETURN]

 -R8000 [RETURN]	reads a file into memory 8000h bytes higher
 -#			than actual load address

 S	Substitute memory values
	GENERAL FORM:	S(start) [RETURN]

 -S100
 0100 01-21 [RETURN]	01H changed to 21H
 0101 BC-0 [RETURN]	BCH changed to 00H
 0102 00-00 [RETURN]	0FH changed to 00H
 0103 C3-=[RETURN]	NOTE:	No change in memory
 0104 3D .		NOTE:	The dot ends the sequence
				as will carriage return alone
 -#

 T	Trace program execution
	GENERAL FORM:	T(number of lines of code)

 -T3 [RETURN]
 C0Z0M0E0I0  A=00 B=0000 D=0000 H=0000 S=0100 P=0100 LXI  H,0000
 C0Z0M0E0I0  A=00 B=0000 D=0000 H=0000 S=0100 P=0100 DAD  SP
 C0Z0M0E0I0  A=00 B=0000 D=0000 H=0100 S=0100 P=0100 LXI  SP,070C
 -#

 U	Un-trace program execution
	Works like 'T' command except nothing is displayed

 V	Verify identical memory blocks
	GENERAL FORM:	V(start),(finish),(target) [RETURN]

 -V100,500,700 [RETURN]
 0105 25 0705 85	In this example, three bytes were found
 01F0 25 07F0 85	to be different
 0485 75 0A85 32
 -#

 W	Write to file
	GENERAL FORM:	W(start),(finish) [RETURN]

 X	eXamine CPU registers or flags
	GENERAL FORM:	X(register or flag) [RETURN]
 -XA
 A=00 01 [RETURN]	'A' register changed from zero to one
 -#

 -XZ
 Z0 [RETURN]		'Z' flag left unchanged
 -#

 Y	n/a
 Z	n/a