page	78,132
	title	Commands for Monitor

	.model	small
	.code
	.data
InitSeg segment byte public
InitSeg ends

DGroup	group	_TEXT,_DATA,InitSeg

	.data

	extrn	DsSave:word, CsSave:word, IpSave:word

DEFLEN	dw	?			;Default length of range
DEFDUMP	dd	?			;Default dump address
ListBuf	db	80 dup(?)

	.code
	assume	cs:DGroup,ds:DGroup,es:DGroup,ss:DGroup

	public	Compare,Dump,Enter,Fill,Input,Move,Output,Search
	public	Default,OutSi

	extrn	OutCh:near, CrLf:near, Command:near
	extrn	InCh:near, Backup:near, Out16:near, Blank:near
	extrn	ScanB:near, ScanP:near, Hex:near, Error:near
	extrn	HexIn:near, HexChk:near, Tab:near, Address:near, GetHex:near
	extrn	GetEol:near

;Print the hex address of SI and DS

OUTSI:
	MOV	DX,DS		;Put DS where we can work with it
	CALL	OUT16		;Display segment
	MOV	DX,SI
	jmp	short OUTADD		;Finish below

;Print digit hex address of DI and ES
;Same as OUTSI above

OUTDI:
	MOV	DX,ES
	CALL	OUT16
	MOV	DX,DI
;Finish OUTSI here too
OUTADD:
	MOV	AL,":"
	CALL	OutCh
	jmp	Out16


;RANGE - Looks for parameters defining an address range.
;The first parameter is a hex number of 5 or less digits
;which specifies the starting address. The second parameter
;may specify the ending address, or it may be preceded by
;"L" and specify a length (4 digits max), or it may be
;omitted and a length of 128 bytes is assumed. Returns with
;segment in AX, displacement in DX, length in CX.

DSRANGE:
	MOV	BP,[DSSave]	;Default segment is DS
	MOV	[DEFLEN],128	;and default length to 128 bytes
RANGE:
	CALL	ADDRESS
	PUSH	AX		;Save segment
	PUSH	DX		;Save offset
	CALL	SCANP		;Get to next parameter
	CMP	AL,"L"		;Length indicator?
	JE	GETLEN
	MOV	DX,[DEFLEN]	;Default length
	CALL	HEXIN		;Second parameter present?
	JC	RNGRET		;If not, use default
	MOV	CX,4		;4 hex digits
	CALL	GETHEX		;Get ending address (same segment)
	MOV	CX,DX		;Low 16 bits of ending addr.
	POP	DX		;Low 16 bits of starting addr.
	SUB	CX,DX		;Compute range
	INC	CX		;Include last location
	POP	AX		;Segment of starting address
	RET

GETLEN:
	INC	SI		;Skip over "L" to length
	MOV	CX,4		;Length may have 4 digits
	CALL	GETHEX		;Get the range
RNGRET:
	MOV	CX,DX		;Length
	POP	DX		;Offset of starting addr.

	POP	AX		;Segment of starting addr.
	RET

DEFAULT:
;DI points to default address and CX has default length
	CALL	SCANP
	JZ	USEDEF		;Use default if no parameters
	CMP	AL,"L"
	JZ	NEWLEN
	MOV	[DEFLEN],CX
	CALL	RANGE
	JMP	GETEOL

NEWLEN:
	INC	SI
	MOV	CX,4
	CALL	GETHEX
	MOV	CX,DX		;Get new length
USEDEF:
	MOV	SI,DI
	LODSW			;Get default displacement
	MOV	DX,AX
	LODSW			;Get default segment
Ret1:	RET


;************************************************************
; "C" command
;Compare one area of memory to another. 

COMPARE:
	CALL	DSRANGE		;Get range of first area
	PUSH	CX		;Save length
	PUSH	AX		;Save segment
	PUSH	DX		;Save offset
	CALL	ADDRESS		;Get second area
	CALL	GETEOL		;Check for errors
	POP	SI
	MOV	DI,DX
	MOV	ES,AX
	POP	DS
	POP	CX		; Length
	DEC	CX
	CALL	COMP		; Do one less than total
	INC	CX		; CX=1 (do last one)
COMP:
REPE	CMPSB
	JZ	RET1
; Compare error. Print address, value; value, address.
	DEC	SI
	CALL	OUTSI
	CALL	BLANK
	CALL	BLANK
	LODSB
	CALL	HEX
	CALL	BLANK
	CALL	BLANK
	DEC	DI
	MOV	AL,ES:[DI]
	CALL	HEX
	CALL	BLANK
	CALL	BLANK
	CALL	OUTDI
	INC	DI
	CALL	CRLF
	XOR	AL,AL
	jmp	COMP


;************************************************************
; "D" command
; Dump an area of memory in both hex and ASCII

DUMP:
	MOV	BP,[DSSave]	;Default segment is DS
	MOV	CX,128
	MOV	DI,offset DGroup:DEFDUMP
	CALL	DEFAULT		;Get range to dump
	MOV	DS,AX		;Set segment
	MOV	SI,DX		;SI has displacement in segment
ROW:
	CALL	OUTSI		;Print address at start of line
	PUSH	SI		;Save address for ASCII dump
	CALL	BLANK
EachByte:
	CALL	BLANK		;Space between bytes
BYTE1:
	LODSB			;Get byte to dump
	CALL	HEX		;and display it
	POP	DX		;DX has start addr. for ASCII dump
	DEC	CX		;Drop loop count
	JZ	ASCII		;If through do ASCII dump
	MOV	AX,SI
	TEST	AL,0FH		;On 16-byte boundary?
	JZ	ENDROW
	PUSH	DX		;Didn't need ASCII addr. yet
	TEST	AL,7		;On 8-byte boundary?
	JNZ	EachByte
	MOV	AL,"-"		;Mark every 8 bytes
	CALL	OutCh
	jmp	BYTE1
ENDROW:
	CALL	ASCII		;Show it in ASCII
	jmp	ROW		;Loop until count is zero
ASCII:
	PUSH	CX		;Save byte count
	MOV	AX,SI		;Current dump address
	MOV	SI,DX		;ASCII dump address
	SUB	AX,DX		;AX=length of ASCII dump
;Compute tab length. ASCII dump always appears on right side
;screen regardless of how many bytes were dumped. Figure 3
;characters for each byte dumped and subtract from 51, which
;allows a minimum of 3 blanks after the last byte dumped.
	MOV	BX,AX
	SHL	AX,1		;Length times 2
	ADD	AX,BX		;Length times 3
	MOV	CX,51
	SUB	CX,AX		;Amount to tab in CX
	CALL	TAB
	MOV	CX,BX		;ASCII dump length back in CX
ASCDMP:
	LODSB			;Get ASCII byte to dump
	AND	AL,7FH		;ASCII uses 7 bits
	CMP	AL,7FH		;Don't try to print RUBOUT
	JZ	NOPRT
	CMP	AL," "		;Check for control characters
	JNC	PRIN
NOPRT:
	MOV	AL,"."		;If unprintable character
PRIN:
	CALL	OutCh		;Print ASCII character
	LOOP	ASCDMP		;CX times
	POP	CX		;Restore overall dump length
	MOV	word ptr ES:[DEFDUMP],SI
	MOV	word ptr ES:[DEFDUMP+2],DS	;Remember last addrss as default
	JMP	CRLF		;Print CR/LF and return


;************************************************************
; "M" command
;Block move one area of memory to another. Overlapping moves
;are performed correctly, i.e., so that a source byte is not
;overwritten until after it has been moved.

MOVE:
	CALL	DSRANGE		;Get range of source area
	PUSH	CX		;Save length
	PUSH	AX		;Save segment
	PUSH	DX		;Save offset
	CALL	ADDRESS		;Get destination address
	CALL	GETEOL		;Check for errors
	POP	SI
	MOV	DI,DX		;Set dest. displacement
	POP	BX		;Source segment
	MOV	DS,BX
	MOV	ES,AX		;Destination segment
	POP	CX		;Length
	CMP	DI,SI		;Check direction of move
	SBB	AX,BX		;Extend the CMP to 32 bits
	JB	COPYLIST	;Move forward into lower mem.
;Otherwise, move backward. Figure end of source and destination
;areas and flip direction flag.
	DEC	CX
	ADD	SI,CX		;End of source area
	ADD	DI,CX		;End of destination area
	std			;Reverse direction
	INC	CX
COPYLIST:
	MOVSB			;Do at least 1 - Range is 1-10000H not 0-FFFFH
	DEC	CX
REP	MOVSB			;Block move
	JMP	COMMAND		;Jump in case stack got trashed by move


;************************************************************
; "F" command
;Fill an area of memory with a list values. If the list
;is bigger than the area, don't use the whole list. If the
;list is smaller, repeat it as many times as necessary.

FILL:
	CALL	DSRANGE		;Get range to fill
	PUSH	CX		;Save length
	PUSH	AX		;Save segment number
	PUSH	DX		;Save displacement
	CALL	LIST		;Get list of values to fill with
	POP	DI		;Displacement in segment
	POP	ES		;Segment
	POP	CX		;Length
	CMP	BX,CX		;BX is length of fill list
	MOV	SI,offset DGroup:ListBuf	;List is in line buffer
	JCXZ	BIGRNG
	JAE	COPYLIST	;If list is big, copy part of it
BIGRNG:
	SUB	CX,BX		;How much bigger is area than list?
	XCHG	CX,BX		;CX=length of list
	PUSH	DI		;Save starting addr. of area
REP	MOVSB			;Move list into area
	POP	SI
;The list has been copied into the beginning of the 
;specified area of memory. SI is the first address
;of that area, DI is the end of the copy of the list
;plus one, which is where the list will begin to repeat.
;All we need to do now is copy [SI] to [DI] until the
;end of the memory area is reached. This will cause the
;list to repeat as many times as necessary.
	MOV	CX,BX		;Length of area minus list
	PUSH	ES		;Different index register
	POP	DS		;requires different segment reg.
	jmp	COPYLIST	;Do the block move


;************************************************************
; "S" command
;Search a specified area of memory for given list of bytes.
;Print address of first byte of each match.

SEARCH:
	CALL	DSRANGE		;Get area to be searched
	PUSH	CX		;Save count
	PUSH	AX		;Save segment number
	PUSH	DX		;Save displacement
	CALL	LIST		;Get search list
	DEC	BX		;No. of bytes in list-1
	POP	DI		;Displacement within segment
	POP	ES		;Segment
	POP	CX		;Length to be searched
	SUB	CX,BX		;  minus length of list
SCAN:
	MOV	SI,offset DGroup:ListBuf	;List kept in line buffer
	LODSB			;Bring first byte into AL
DOSCAN:
	SCASB			;Search for first byte
	LOOPNE	DOSCAN		;Do at least once by using LOOP
	JNZ	RET2		;Exit if not found
	PUSH	BX		;Length of list minus 1
	XCHG	BX,CX
	PUSH	DI		;Will resume search here
REPE	CMPSB			;Compare rest of string
	MOV	CX,BX		;Area length back in CX
	POP	DI		;Next search location
	POP	BX		;Restore list length
	JNZ	TestEndScan	;Continue search if no match
	DEC	DI		;Match address
	CALL	OUTDI		;Print it
	INC	DI		;Restore search address
	CALL	CRLF
TestEndScan:
	JCXZ	RET2
	jmp	SCAN		;Look for next occurrence


;Process one parameter when a list of bytes is
;required. Carry set if parameter bad. Called by LIST

LISTITEM:
	CALL	SCANP		;Scan to parameter
	CALL	HEXIN		;Is it in hex?
	JC	STRINGCHK	;If not, could be a string
	MOV	CX,2		;Only 2 hex digits for bytes
	CALL	GETHEX		;Get the byte value
	MOV	[BX],DL		;Add to list
	INC	BX
GRET:	CLC			;Parameter was OK
Ret2:	RET

STRINGCHK:
	MOV	AL,[SI]		;Get first character of param
	CMP	AL,"'"		;String?
	JZ	STRING
	CMP	AL,'"'		;Either quote is all right
	JZ	STRING
	STC			;Not string, not hex - bad
	RET

STRING:
	MOV	AH,AL		;Save for closing quote
	INC	SI
STRNGLP:
	LODSB			;Next char of string
	CMP	AL,13		;Check for end of line
	JZ	ErrorJ		;Must find a close quote
	CMP	AL,AH		;Check for close quote
	JNZ	STOSTRG		;Add new character to list
	CMP	AH,[SI]		;Two quotes in a row?
	JNZ	GRET		;If not, we're done
	INC	SI		;Yes - skip second one
STOSTRG:
	MOV	[BX],AL		;Put new char in list
	INC	BX
	jmp	STRNGLP		;Get more characters

ErrorJ:	jmp	Error

;Get a byte list for ENTER, FILL or SEARCH. Accepts any number
;of 2-digit hex values or character strings in either single
;(') or double (") quotes.

LIST:
	MOV	BX,offset DGroup:ListBuf	;Put byte list in the line buffer
LISTLP:
	CALL	LISTITEM	;Process a parameter
	JNC	LISTLP		;If OK, try for more
	SUB	BX,offset DGroup:ListBuf	;BX now has no. of bytes in list
	JZ	ErrorJ		;List must not be empty
	jmp	GetEol


;************************************************************
; "E" command

;Short form of ENTER command. A list of values from the
;command line are put into memory without using normal
;ENTER mode.

GETLIST:
	CALL	LIST		;Get the bytes to enter
	POP	DI		;Displacement within segment
	POP	ES		;Segment to enter into
	MOV	SI,offset DGroup:ListBuf	;List of bytes is in line buffer
	MOV	CX,BX		;Count of bytes
REP	MOVSB			;Enter that byte list
	RET

;Enter values into memory at a specified address. If the
;line contains nothing but the address we go into "enter
;mode", where the address and its current value are printed
;and the user may change it if desired. To change, type in
;new value in hex. Backspace works to correct errors. If
;an illegal hex digit or too many digits are typed, the
;bell is sounded but it is otherwise ignored. To go to the
;next byte (with or without change), hit space bar. To
;back up to a previous address, type "-". On
;every 8-byte boundary a new line is started and the address
;is printed. To terminate command, type carriage return.
;   Alternatively, the list of bytes to be entered may be
;included on the original command line immediately following
;the address. This is in regular LIST format so any number
;of hex values or strings in quotes may be entered.

ENTER:
	MOV	BP,[DSSave]	;Default segment
	CALL	ADDRESS		;Get ENTER address
	PUSH	AX		;Save for later
	PUSH	DX
	CALL	SCANB		;Any more parameters?
	JNZ	GETLIST		;If not end-of-line get list
	POP	DI		;Displacement of ENTER
	POP	ES		;Segment
GETROW:
	CALL	OUTDI		;Print address of entry
	CALL	BLANK		;Leave a space
	CALL	BLANK
GETBYTE:
	MOV	AL,ES:[DI]		;Get current value
	CALL	HEX		;And display it
	MOV	AL,"."
	CALL	OutCh		;Prompt for new value
	MOV	CX,2		;Max of 2 digits in new value
	MOV	DX,0		;Intial new value
GETDIG:
	CALL	InCh		;Get digit from user
	MOV	AH,AL		;Save
	CALL	HEXCHK		;Hex digit?
	XCHG	AH,AL		;Need original for echo
	JC	NOHEX		;If not, try special command
	CALL	OutCh		;Echo to console
	MOV	DH,DL		;Rotate new value
	MOV	DL,AH		;And include new digit
	LOOP	GETDIG		;At most 2 digits
;We have two digits, so all we will accept now is a command.
WaitCh:
	CALL	InCh		;Get command character
NOHEX:
	CMP	AL,8		;Backspace
	JZ	BS
	CMP	AL,7FH		;RUBOUT
	JZ	BS
	CMP	AL,"-"		;Back up to previous address
	JZ	PREV
	CMP	AL,13		;All done with command?
	JZ	EOL
	CMP	AL," "		;Go to next address
	JZ	NEXT
;If we got here, character was invalid. Sound bell.
	MOV	AL,7
	CALL	OutCh
	JCXZ	WaitCh		;CX=0 means no more digits
	jmp	GETDIG		;Don't have 2 digits yet

BS:
	CMP	CL,2		;CX=2 means nothing typed yet
	JZ	GETDIG		;Can't back up over nothing
	INC	CL		;Accept one more character
	MOV	DL,DH		;Rotate out last digit
	MOV	DH,CH		;Zero this digit
	CALL	BACKUP		;Physical backspace
	jmp	GETDIG		;Get more digits

;If new value has been entered, convert it to binary and
;put into memory. Always bump pointer to next location

STORE:
	CMP	CL,2		;CX=2 means nothing typed yet
	JZ	NOSTO		;So no new value to store
;Rotate DH left 4 bits to combine with DL and make a byte value
	PUSH	CX
	MOV	CL,4
	SHL	DH,CL
	POP	CX
	OR	DL,DH		;Hex is now converted to binary
	MOV	ES:[DI],DL		;Store new value
NOSTO:
	INC	DI		;Prepare for next location
	RET

EOL:
	CALL	STORE		;Enter the new value
	JMP	CRLF		;CR/LF and terminate

NEXT:
	CALL	STORE		;Enter new value
	INC	CX		;Leave a space plus two for
	INC	CX		;  each digit not entered
	CALL	TAB
	MOV	AX,DI		;Next memory address
	AND	AL,7		;Check for 8-byte boundary
	JNZ	GETBYTE		;Take 8 per line
NEWROW:
	CALL	CRLF		;Terminate line
	JMP	GETROW		;Print address on new line

PREV:
	CALL	STORE		;Enter the new value
;DI has been bumped to next byte. Drop it 2 to go to previous addr
	DEC	DI
	DEC	DI
	jmp	NEWROW		;Terminate line after backing up


;************************************************************
; "I" command
;Input from the specified port and display result

INPUT:
	MOV	CX,4		;Port may have 4 digits
	CALL	GETHEX		;Get port number in DX
	in	al,dx		;Variable port input
	CALL	HEX		;And display
	JMP	CRLF


;************************************************************
; "O" command
;Output a value to specified port.

OUTPUT:
	MOV	CX,4		;Port may have 4 digits
	CALL	GETHEX		;Get port number
	PUSH	DX		;Save while we get data
	MOV	CX,2		;Byte output only
	CALL	GETHEX		;Get data to output
	XCHG	AX,DX		;Output data in AL
	POP	DX		;Port in DX
	out	dx,al		;Variable port output
	RET

;************************************************************

InitSeg	segment
	assume	cs:DGroup,ds:Dgroup

	mov	ax,[DsSave]
	mov	word ptr [DefDump+2],ax
	mov	word ptr [DefDump],100H
InitSeg	ends

end