.Z80
	ASEG

; MXH-AMNZ.Z80
; MEX+ overlay for the Ampro Little Board computer
 
; Version 1.4: 06 Feb 1990
;     * Added routine to send 300ms BREAK using T-mode-esc-@     
;                                                 Bruce McIntosh


; Version 1.3: 28 Jan 1990
;     * Renamed to be assemblable by SLR assembler
;     * Made overlay compatible with MEX+ as per instructions 
;       in -READ.ME on MEX+ distribution disk 
;     * DCD and ring routines Z80-fied copies of similar
;       routines in Bob Connelly's MXH-AM11.ASM
;     * Slightly modified code that finds address of real
;       BIOS to correct a couple of incorrect offsets
;                                                 Bruce McIntosh

; MXO-AMxx.ASM
; MEX overlay for the Ampro Little Board Computer

; Version 1.2: 23 Jul 1988
;	added routine to allow this overlay to find original
;	bios under manually installed or nz-com system.
;						al grabauskas

; Version 1.1:  1 Oct 1986
;     ( added support for dropping DTR for those modems that
;       support it.  -Marc Wilson                            )
;
; Version 1.0: 28 Nov 1984  

REV	EQU	14		; Overlay revision level


; This is a MEX overlay file for the Ampro Computer.  It is designed
; to work with the modem connected to serial port 'B'.  It also       
; requires the CTC and SIO parameter tables at the front of the
; Ampro bios, as well as the I/O initialization routine in the
; Ampro bios.  This is a non-standard bios call and if not present
; in the bios it must be duplicated in this overlay.

; Note that all overlays may freely use memory up to 0CFFH.  If the
; overlay must work with the MEX Smartmodem overlay (MXO-SMxx.ASM),
; the physical modem overlay should terminate by 0AFFH.
	
;------------------------------------------------------------

; Misc equates

NO	EQU	0
YES	EQU	0FFH
TPA	EQU	100H
CR	EQU	13
LF	EQU	10
TAB	EQU	9

; Ampro definitions

IOINT	EQU	57		; BIOS call of initialization routine
SIOB	EQU	52H		; Relative location in bios
SIOB1	EQU	53H
SIOB3	EQU	55H		; Z80DART write register 5
SIOB5	EQU	57H		; Z80DART write register 3
CT1	EQU	42H

; port definitions

MODCTL	EQU	8CH		; Modem control port B
MODDAT	EQU	88H		; Modem data port B

; bit definitions

MDRCVB	EQU	01H		; Modem receive bit (DAV)
MDRCVR	EQU	01H		; Modem receive ready
MDSNDB	EQU	04H		; Modem send bit
MDSNDR	EQU	04H		; Modem send ready bit

; MEX service processor stuff ... MEX supports an overlay service
; processor, located at 0D00H (and maintained at this address from
; version to version).  If your overlay needs to call BDOS for any
; reason, it should call MEX instead; function calls below about
; 240 are simply passed on to the BDOS (console and list I/O calls
; are specially handled to allow modem port queueing, which is why
; you should call MEX instead of BDOS).  MEX uses function calls
; above about 244 for special overlay services (described below).

; Some sophisticated overlays may need to do file I/O; if so, use
; the PARSFN MEX call with a pointer to the FCB in DE to parse out
; the name.  This FCB should support a spare byte immediately pre-
; ceeding the actual FCB (to contain user # information).  If you've
; used MEX-10 for input instead of BDOS-10 (or you're parsing part
; of a SET command line that's already been input), then MEX will
; take care of DU specs, and set up the FCB accordingly.  There-
; after all file I/O calls done through the MEX service processor
; will handle drive and user with no further effort necessary on
; the part of the programmer.

MEX	EQU	0D00H		; Address of the service processor
INMDM	EQU	255		; Get char from port to A, CY=no more in 100 ms
TIMER	EQU	254		; Delay 100ms * reg B
TMDINP	EQU	253		; B=# secs to wait for char, cy=no char
CHEKCC	EQU	252		; Check for ^C from KBD, Z=present
SNDRDY	EQU	251		; Test for modem-send ready
RCVRDY	EQU	250		; Test for modem-receive ready
SNDCHR	EQU	249		; Send a character to the modem (after sndrdy)
RCVCHR	EQU	248		; Recv a char from modem (after rcvrdy)
LOOKUP	EQU	247		; Table search: see CMDTBL comments for info
PARSFN	EQU	246		; Parse filename from input stream
BDPARS	EQU	245		; Parse baud-rate from input stream
SBLANK	EQU	244		; Scan input stream to next non-blank
EVALA	EQU	243		; Evaluate numeric from input stream
LKAHED	EQU	242		; Get nxt char w/o removing from input
GNC	EQU	241		; Get char from input, cy=1 if none
ILP	EQU	240		; Inline print
DECOUT	EQU	239		; Decimal output
PRBAUD	EQU	238		; Print baud rate

CONOUT	EQU	2		; Simulated BDOS function 2: console char out
PRINT	EQU	9		; Simulated BDOS function 9: print string
INBUF	EQU	10		; Input buffer, same structure as BDOS 10

	ORG	TPA		; We begin

; Changed DS 3 per -READ.ME to flag overlay as LOADable by MEX+

	DB	0C3H		; mark overlay as LOADable
	DS	2		; space for JP START address in MEX

; The following variables are located at the beginning of the program
; to facilitate modification without the need of re-assembly. They will
; be moved in MEX 2.0.

PMODEM:	DB	NO		; Yes=PMMI modem \ / These 2 locations are not
SMODEM:	DB	NO 		; Yes=Smartmodem / \ referenced by MEX
TPULSE:	DB	'T'		; T=touch, P=pulse (not referenced by MEX)
CLOCK:	DB	40		; Clock speed x .1, up to 25.5 mhz.
MSPEED:	DB	6		; Sets display time for sending a file
				; 0=110	1=300  2=450  3=600  4=710
				; 5=1200 6=2400 7=4800 8=9600 9=19200
BYTDLY:	DB	5		; Default time to send character in
				; Terminal mode file transfer (0-9)
				; 0=0 delay, 1=10 ms, 5=50 ms, 9=90 ms
CRDLY:	DB	5		; End-of-line delay after CRLF in terminal
				; Mode file transfer for slow BBS systems
				; 0=0 delay, 1=100 ms, 5=500 ms, 9=900 ms
COLUMS:	DB	5		; Number of directory columns
SETFL:	DB	YES		; Yes=user-defined SET command
SCRTST:	DB	YES		; Yes=if home cursor and clear screen
				; Routine at CLRSCRN
	DB	0		; Was once ACKNAK, now spare
BAKFLG:	DB	NO		; Yes=make .BAK file
CRCDFL:	DB	YES		; Yes=default to CRC checking
				; No=default to Checksum checking
TOGCRC:	DB	YES		; Yes=allow toggling of Checksum to CRC
CVTBS:	DB	NO		; Yes=convert backspace to rub
TOGLBK:	DB	YES		; Yes=allow toggling of bksp to rub
ADDLF:	DB	NO		; No=no LF after CR to send file in
				; Terminal mode (added by remote echo)
TOGLF:	DB	YES		; Yes=allow toggling of LF after CR
TRNLOG:	DB	YES		; Yes=allow transmission of logon
				; Write logon sequence at location LOGON
SAVCCP:	DB	YES		; Yes=do not overwrite CCP
LOCNXT:	DB	NO		; Yes=local cmd if EXTCHR precedes
				; No=not local cmd if EXTCHR precedes
TOGLOC:	DB	YES		; Yes=allow toggling of LOCNXTCHR
LSTTST:	DB	YES		; Yes=allow toggling of printer on/off
				; In terminal mode. Set to no if using
				; The printer port for the modem
XOFTST:	DB	YES		; Yes=allow testing of XOFF from remote
				; While sending a file in terminal mode
XONWT:	DB	NO		; Yes=wait for XON after sending CR while
				; Transmitting a file in terminal mode	
TOGXOF:	DB	YES		; Yes=allow toggling of XOFF testing
IGNCTL:	DB	NO 		; Yes=do not send control characters
				; Above CTL-M to CRT in terminal mode
				; No=send any incoming CTL-char to CRT
EXTRA1:	DB	0		; For future expansion
EXTRA2:	DB	0		; For future expansion
BRKCHR:	DB	'@'-40H		; ^@ = Send a 300 ms. break tone
NOCONN:	DB	'N'-40H		; ^N = Disconnect from phone line
LOGCHR:	DB	'L'-40H		; ^L = Send logon
LSTCHR:	DB	'P'-40H		; ^P = Toggle printer
UNSVCH:	DB	'R'-40H		; ^R = Close input text buffer
TRNCHR:	DB	'T'-40H		; ^T = Transmit file to remote
SAVCHR:	DB	'Y'-40H		; ^Y = Open input text buffer
EXTCHR:	DB	'^'-40H		; ^^ = Send next character

	DS	2		; Make addresses right

; Low-level modem I/O routines: this will be replaced with
; a jump table in MEX 2.0 (you can insert jumps here to longer
; routines if you'd like ... I'd recommend NOT putting part of
; a routine in this area, then jumping to the rest of the routine
; in the non-fixed area; that will complicate the 2.0 conversion)

INCTL1:	IN	A,(MODCTL)	; In modem control port
	RET
	DB	0,0,0,0,0,0,0	; Spares if needed for non-PMMI

OTDATA:	OUT	(MODDAT),A	; Out modem data port
	RET
	DB	0,0,0,0,0,0,0	; Spares if needed for non=PMMI

INPORT:	IN	A,(MODDAT)	; In modem data port
	RET
	DB	0,0,0,0,0,0,0	; Spares if needed for non-PMMI

; Bit-test routines.  These will be merged with the above
; routines in MEX 2.0 to provide a more reasonable format

MASKR:	AND	MDRCVB
	RET			; Bit to test for receive ready
TESTR:	CP	MDRCVR
	RET			; Value of receive bit when ready
MASKS:	AND	MDSNDB
	RET			; Bit to test for send ready
TESTS:	CP	MDSNDR
	RET			; Value of send bit when ready

; Unused area: was once used for special PMMI functions,
; Now used only to retain compatibility with MDM overlays.
; You may use this area for any miscellaneous storage you'd
; like but the length of the area *must* be 12 bytes.

; Added jumps to DCD and ring detect routines for MEX+ at 0157H.
; DS 3 pads keep length 12 bytes, as required in comments above.

	DS	3      
DCDTST: JP	DCDVEC		; DCD test routine
RNGTST: JP	RNGVEC		; ring test routine
	DS	3

; Special modem function jump table: if your overlay cannot handle
; some of these, change the jump to "DS 3", so the code present in
; MEX will be retained.  Thus, if your modem can't dial, change the
; JMP PDIAL at DIALV to DS 3, and MEX will print a "not-implemented"
; diagnostic for any commands that require dialing.

; DIALV  dials the digit in A. See the comments at PDIAL for specs.

; DISCV  disconnects the modem

; GOODBV is called just before MEX exits to CP/M.  If your overlay
;        requires some exit cleanup, do it here.

; INMODV is called when MEX starts up; use INMODV to initialize the modem.

; NEWBDV is used for phone-number baud rates and is called with a baud-rate
;        code in the A register, value as follows:

;	 A=0:   110 baud       A=1:   300 baud      A=2:   450 baud
;	 A=3:   600 baud       A=4:   710 baud      A=5:  1200 baud
;	 A=6:  2400 baud       A=7:  4800 baud      A=8: 19200 baud

;        If your overlay supports the passed baud rate, it should store the
;	 value passed in A at MSPEED (107H), and set the requested rate. If
;	 the value passed is not supported, you should simply return (with-
;	 out modifying MSPEED) -or- optionally request a baud-rate from the
;	 user interactively.

; NOPARV is called at the end of each file transfer; your overlay may simply
;	 return here, or you may want to restore parity if you set no-parity
;	 in the following vector (this is the case with the PMMI overlay).
	
; PARITV is called at the start of each file transfer; your overlay may simply
;	 return here, or you may want to enable parity detection (this is the
;	 case with the PMMI overlay).

; SETUPV is the user-defined command ... to use this routine to build your own
;	 MEX command, set the variable SETFL (117H) non-zero, and add your SET
;	 code.  You can use the routine presented in the PMMI overlay as a 
;	 guide for parsing, table lookup, etc.

; SPMENU is provided only for MDM compatibility, and is not used by MEX 1.0 for
;	 any purpose (it will be gone in MEX 2).

; VERSNV is called immediately after MEX prints its sign-on message at cold
;	 startup -- use this to identify your overlay in the sign-on message
;	 (include overlay version number in the line).
; BREAKV is provided for sending a BREAK (<ESC>-B in terminal mode).  If your
;	 modem doesn't support BREAK, or you don't care to code a BREAK rou-
;	 tine, you may simply execute a RET instruction.

LOGON:	DS	2		; Needed for MDM compat, not ref'd by MEX
DIALV:	DS	3		; Dial digit in A (see info at PDIAL)
DISCV:	JP	HANGUP		; Disconnect the modem
GOODBV:	DS	3		; Called before exit to CP/M
INMODV:	JP	NITMOD		; Initialization. Called at cold-start
NEWBDV:	JP	PBAUD		; Set baud rate
NOPARV:	JP	NOPAR		; Set modem for no-parity
PARITV:	JP	PARITY		; Set modem parity
SETUPV:	JP	SETCMD		; SET cmd: jump to a RET if you don't write SET
SPMENV:	DS	3		; Not used with MEX
VERSNV:	JP	SYSVER		; Overlay's voice in the sign-on message
BREAKV:	JP	SNDBRK		; Send a break

; The following jump vector provides the overlay with access to special
; routines in the main program (retained and supported in the main pro-
; gram for MDM overlay compatibility). These should not be modified by
; the overlay.

; Note that for MEX 2.0 compatibility, you should not try to use these
; routines, since this table will go away with MEX 2.0 (use the MEX
; service call processor instead).

ILPRTV:	DS	3		; Replace with MEX function 9
INBUFV:	DS	3		; Replace with MEX function 10
ILCMPV:	DS	3		; Replace with table lookup funct. 247
INMDMV:	DS	3		; Replace with MEX function 255
NXSCRV:	DS	3		; Not supported by MEX (returns w/no action)
TIMERV:	DS	3		; Replace with MEX function 254

; Clear/screen and clear/end-of-screen. Each routine must use the
; full 9 bytes alloted (may be padded with nulls).

; These routines (and other screen routines that MEX 2.0 will sup-
; port) will be accessed through a jump table in 2.0, and will be
; located in an area that won't tie the screen functions to the
; modem overlay (as the MDM format does).

CLREOS:	LD	DE,EOSMSG
	LD	C,PRINT
	CALL	MEX
	RET

CLS:	LD	DE,CLSMSG	; Null unless patched
	LD	C,PRINT
	CALL	MEX
 	RET

; The following ORG is required because MEX+ reserves all space
; after the CLS routine above up to 200H (1A7-200).

	ORG	0200H

EOSMSG:	DB	00,00,0,0,0,'$'
CLSMSG:	DB	00,00,0,0,0,'$'

NOPAR:	RET

PARITY:	RET

;------------------------------------------------------------------
;
; This routine sets DTR and RTS low for 1 second to disconnect the phone.
; This code comes from I2AM-1D.ASM.
;
;HANGUP:
;	MVI	B,'S'-40H	; X-off to stop host if needed
;	CALL	OUTDATA
;	MVI	B,1		; Wait a moment to let it react
;       MVI     C,TIMER
;	CALL	MEX
HANGUP:	LD	A,5
	OUT	(MODCTL),A	; Send to the status port
	LD	A,068H		; Turn off DTR, RTS, send break*
                                ; *(According to Z80DART data sheet,
                                ;   xxx1xxxx sends break, so 068H
                                ;   actually does NOT send break)
	OUT	(MODCTL),A
	LD	B,10		; Wait 1 second
	LD	C,TIMER
	CALL	MEX
	LD	A,5
	OUT	(MODCTL),A
	LD	A,0EAH		; Restore normal, 8 bits, RTS on, etc.
	OUT	(MODCTL),A
	RET

; DCD and ring detect routines, Z80-fied from Bob Connelly's 
; MXH-AMNZ.ASM.  Added code to save/restore 16bit registers.
 
DCDVEC: PUSH	BC
	PUSH	DE
	PUSH	HL
	LD	A,010H
	OUT	(MODCTL),A
	IN	A,(MODCTL)
	AND	020H		; modem DCD must be tied to LB CTS 
	POP	HL
	POP	DE
	POP	BC
	RET	Z		; return 00 if DCD low
	OR	0FFH		; return FF if DCD high
	RET

; Ring routine is pointless on LB, as RI lines on Z80DART are
; used on the board for something else.  So, return 00.

RNGVEC: XOR	A
	RET

SNDBRK: PUSH	AF		; save everything
	PUSH	BC
	PUSH	DE
	PUSH	HL
	LD	A,5		; tell DART to get ready for WR5
	OUT	(MODCTL),A
	LD	HL,(BIOSADDR)	; get BIOS address
	LD	L,SIOB3		; point to Write register 5 data
	LD	A,(HL)		; get WR5 data
	OR	10H		; start sending break
	OUT	(MODCTL),A
	LD	B,3		; wait 300ms
	LD	C,TIMER
	CALL	MEX
	LD	A,5		; tell DART to get ready for WR5
	OUT	(MODCTL),A
	LD	HL,(BIOSADDR)	; get BIOS address
	LD	L,SIOB3		; point to WR5 data
	LD	A,(HL)		; get WR5 data
	OUT	(MODCTL),A	; stop sending break
	POP	HL		; restore everything
	POP	DE
	POP	BC
	POP	AF
	RET

;--------------------------------------------------------------
;

NITMOD:	LD	A,6		; Initialize to 2400 baud.  No other
				; Parameters changed... fall thru

	CALL	GRABBIOS	; get bios address, whether nz-com
				;   or not. returned in "biosaddr:"

PBAUD:	PUSH	HL		; Don't alter anybody
	PUSH	DE
	PUSH	BC
	LD	E,A		; Code to DE
	LD	D,0
	LD	HL,BAUDTB	; Offset into table
	ADD	HL,DE
	LD	A,(HL)		; Fetch code
	OR	A		; 0? (means unsupported code)
	SCF			; Return error for STBAUD caller
	JP	Z,PBEXIT	; Exit if so
	LD	(BSAVE1),A	; Save it
	LD	A,E		; Get speed code back
	LD	(MSPEED),A	; Make it current
	LD	HL,BAUDTX	; Offset into second table
	ADD	HL,DE
	LD	A,(HL)		; Get second value
	LD	(BSAVE2),A	; Save it also
	LD	HL,(BIOSADDR)	; Get location of bios
	LD	L,CT1		; Add 42 to reach CT1 in i/o table
	LD	A,47H
	LD	(HL),A
	INC	HL		; Move to next location
	LD	A,(BSAVE1)	; Get first table value
	LD	(HL),A		; Store it
	LD	A,(BSAVE2)	; Get second table value
	LD	B,A		; And save it
	LD	L,SIOB1		; Move ahead to siob+1 values
	LD	A,(HL)		; Get current value
	AND	3FH
	OR	B		; Or it with second value
	LD	(HL),A		; Store it in work table
	INC	HL
	INC	HL
	LD	A,(HL)		; Get last value and make
	OR	80H		; Sure msb is set
	LD	(HL),A		; Put it back in working table
	CALL	IOINIT		; Do the initialization
	SCF
	CCF			; Return no error for STBAUD
PBEXIT:	POP	BC		; All done
	POP	DE
	POP	HL
	RET

IOINIT:	LD	A,IOINT		; Offset into bios jump table
	LD	HL,(BIOSADDR)	; Address of bios in HL
	LD	L,A		; Add offset
	JP	GOHL		; And go there with auto return

; table of baud rate divisors for supported rates

BAUDTB:	DB	0,208,139,208,0,104 ; 110,300,450,600,710,1200
	DB	52,26,13,0	; 2400,4800,9600,19200

BAUDTX:	DB	0,80H,80H,40H,0,40H
	DB	40H,40H,40H,0

BSAVE1:	DB	0		; Current setting from
BSAVE2:	DB	0		; Tables - uninitialized

; Sign-on message

SYSVER:	LD	DE,SOMESG
	LD	C,PRINT
	CALL	MEX
	RET

SOMESG:	DB	'Ampro Overlay Version '
	DB	REV/10+'0'
	DB	'.'
	DB	REV MOD 10+'0'
	DB	' (nz-com compatible)'
	DB	CR,LF,'$'

; Newline on console

CRLF:	LD	A,CR
	CALL	TYPE
	LD	A,LF		; Fall into TYPE

; type char in A on console

TYPE:	PUSH	HL		; Save 'em
	PUSH	DE
	PUSH	BC
	LD	E,A		; Align output character
	LD	C,CONOUT	; Print via MEX
	CALL	MEX
	POP	BC
	POP	DE
	POP	HL
	RET

; Data area

;------------------------------------------------------------

; The remainder of this overlay implements a very versatile
; SET command -- if you prefer not to write a SET for your
; modem, you may delete the code from here to the END statement.

; Control is passed here after MEX parses a SET command.

SETCMD:	LD	C,SBLANK	; Any arguments?
	CALL	MEX
	JP	C,SETSHO	; If not, go print out values
	LD	DE,CMDTBL	; Parse command
	CALL	TSRCH		; From table
	PUSH	HL		; Any address on stack
	RET	NC		; If we have one, execute it
	POP	HL		; Nope, fix stack
SETERR:	LD	DE,SETEMS	; Print error
	LD	C,PRINT
	CALL	MEX
	RET

SETEMS:	DB	CR,LF,'SET command error',CR,LF,'$'

; SET command table ... note that tables are constructed of command-
; name (terminated by high bit=1) followed by word-data-value returned
; in HL by MEX service processor LOOKUP.  Table must be terminated by
; a binary zero.

; Note that LOOKUP attempts to find the next item in the input stream
; in the table passed to it in HL ... if found, the table data item is
; returned in HL; if not found, LOOKUP returns carry set.

CMDTBL:	DB	'?'+80H		; "set ?"
	DW	STHELP
	DB	'BAU','D'+80H	; "set baud"
	DW	STBAUD
	DB	'BIT','S'+80H	; "set bits"
	DW	STBITS
	DB	'PARIT','Y'+80H	; "set parity"
	DW	STPAR
	DB	'STO','P'+80H	; "set stop"
	DW	STSTOP
	DB	'SHAK','E'+80H	; "set shake"
	DW	STSHAK

	DB	0		; <<=== table terminator

; SET <no-args>: print current statistics

SETSHO:	LD	HL,SHOTBL	; Get table of SHOW subroutines
SETSLP:	LD	E,(HL)		; Get table address
	INC	HL
	LD	D,(HL)
	INC	HL
	LD	A,D		; End of table?
	OR	E
	RET	Z		; Exit if so
	PUSH	HL		; Save table pointer
	EX	DE,HL		; Adrs to HL
	CALL	GOHL		; Do it
	CALL	CRLF		; Print newline
	LD	C,CHEKCC	; Check for console abort
	CALL	MEX
	POP	HL		; It's done
	JP	NZ,SETSLP	; Continue if no abort
	RET

GOHL:	JP	(HL)

; table of SHOW subroutines

SHOTBL:	DW	BDSHOW
	DW	BITSH
	DW	PARSH
	DW	STPSH
	DW	SHKSH
	DW	0		; <<== table terminator

; SET ?  processor

STHELP:	LD	DE,HLPMSG
	LD	C,PRINT
	CALL	MEX
	RET

; The help message

HLPMSG:	DB	CR,LF,'SET command, Ampro version:',CR,LF
	DB	CR,LF,'  >SET BAUD 300, 450, 600, 1200, 2400, 4800, or 9600.'
	DB	CR,LF,'  >SET BITS 5, 6, 7, or 8.'
	DB	CR,LF,'  >SET PARITY ODD, EVEN, or NONE.'
	DB	CR,LF,'  >SET STOP 1, or 2.'
	DB	CR,LF,'  >SET SHAKE ON, or OFF.'
	DB	CR,LF,CR,LF,'$'

; SET BAUD processor

STBAUD:	LD	C,BDPARS	; Function code
	CALL	MEX		; Let MEX look up code
	JP	C,SETERR	; Invalid code
	CALL	PBAUD		; No, try to set it
	JP	C,SETERR	; Not-supported code
BDSHOW:	CALL	ILPRT		; Display baud
	DB	'  Baud rate: ',0
	LD	A,(MSPEED)
	LD	C,PRBAUD	; Use MEX routine
	CALL	MEX
	RET

; SET BITS processor

STBITS:	LD	DE,BITTBL	; Load lookup table
	CALL	TSRCH		; Look for 7 or 8
	JP	C,SETERR	; If not found
	LD	C,L		; Save selection value
	LD	HL,(BIOSADDR)	; Get bios address
	LD	L,SIOB3		; Move to siob+3
	LD	A,(HL)		; Wr5 info 
	AND	9FH		; Mask
	OR	C		; Add selection
	LD	(HL),A		; Store it
	LD	A,C		; Get selection
	RLA
	LD	C,A		; Shift selection left
	LD	L,SIOB5		; Move to siob+5
	LD	A,(HL)		; Wr3 info
	AND	3FH		; Mask
	OR	C
	LD	(HL),A		; Store it
	CALL	IOINIT		; Do it.

BITSH:	CALL	ILPRT
	DB	'  Data bits: ',0
	LD	HL,(BIOSADDR)	; Get bios location
 	LD	L,SIOB3		; Move to siob+3
	LD	A,(HL)		; Get current value
	AND	60H
	CP	60H
	JP	Z,BITSH8
	CP	20H
	JP	Z,BITSH7
	CP	40H
	JP	Z,BITSH6
	CALL	ILPRT
	DB	'5',0		; Show a 5
	RET
BITSH6:	CALL	ILPRT
	DB	'6',0		; Show a 6
	RET
BITSH7:	CALL	ILPRT
	DB	'7',0		; Show a 7
	RET
BITSH8:	CALL	ILPRT
	DB	'8',0
	RET

BITTBL:	DB	'5'+80H
	DW	00H
	DB	'6'+80H
	DW	40H
	DB	'7'+80H
	DW	20H
	DB	'8'+80H
	DW	60H
	DB	0
;
STPAR:	LD	DE,PARTBL
	CALL	TSRCH
	JP	C,SETERR
	LD	C,L
	LD	HL,(BIOSADDR)	; Get bios address
	LD	L,SIOB1		; Go to siob+1
	LD	A,(HL)
	AND	0FCH
	OR	C
	LD	(HL),A
	CALL	IOINIT

PARSH:	CALL	ILPRT
	DB	'     Parity: ',0
	LD	HL,(BIOSADDR)	; Get bios address
	LD	L,SIOB1
	LD	A,(HL)
	AND	03H		; Mask
	CP	01H		; Check for none
	JP	Z,PARSHO
	CP	03H
	JP	Z,PARSHE

	CALL	ILPRT
	DB	'none',0
	RET

PARSHO:	CALL	ILPRT
	DB	'odd',0
	RET
PARSHE:	CALL	ILPRT
	DB	'even',0
	RET

PARTBL:	DB	'OD','D'+80H
	DW	01H
	DB	'EVE','N'+80H
	DW	03H
	DB	'NON','E'+80H
	DW	00H
	DB	0

STSTOP:	LD	DE,STPTBL
	CALL	TSRCH
	JP	C,SETERR
	LD	C,L
	LD	HL,(BIOSADDR)	; Get bios address
	LD	L,53H		; Shift to bios+1
	LD	A,(HL)
	AND	0F3H
	OR	C
	LD	(HL),A
	CALL	IOINIT

STPSH:	CALL	ILPRT
	DB	'  Stop bits: ',0
	LD	HL,(BIOSADDR)	; Get bios address
	LD	L,53H		; Shift to bios+1
	LD	A,(HL)
	AND	0CH
	CP	0CH
	JP	Z,STPSH2
	CALL	ILPRT
	DB	'1',0
	RET
STPSH2:	CALL	ILPRT
	DB	'2',0
	RET
STPTBL:	DB	'1'+80H
	DW	04H
	DB	'2'+80H
	DW	0CH
	DB	0

STSHAK:	LD	DE,SHKTBL	; Get handshake table
	CALL	TSRCH		; Search it for parameter
	JP	C,SETERR	; If not found
	LD	C,L		; Temp store value in C
	LD	HL,(BIOSADDR)	; Get location of BIOS
	LD	L,6DH		; Location of HSB in bios
	LD	(HL),C		; Put new value in it

SHKSH:	CALL	ILPRT
	DB	' Hand Shake: ',0
	LD	HL,(BIOSADDR)	; Get bios location
	LD	L,6DH		; Location of HSB in bios
	LD	A,(HL)		; Get current value
	CP	1
	JP	Z,SHKSHY	; Show a yes
	CALL	ILPRT
	DB	'off',0
	RET
SHKSHY:	CALL	ILPRT
	DB	'on',0
	RET

SHKTBL:	DB	'OF','F'+80H
	DW	0
	DB	'O','N'+80H
	DW	1
	DB	0

;----------------------------------------------------------

; Compare next input-stream item in table @DE; CY=1
; if not found, else HL=matched data item

TSRCH:	LD	C,LOOKUP	; Get function code
	JP	MEX		; Pass to MEX processor

; Print in-line message ... blows away C register

ILPRT:	LD	C,ILP		; Get function code
	JP	MEX		; Go do it

;------------------------------------------------------------
; This is a callable routine that locates the bios address
; whether nz-com is running or not and saves it in the word
; at "biosaddr:". It gets run once at mex initialization.
; All points in the code that used to get this address from
; location one now get it from the located and saved address.

GRABBIOS:
	PUSH	HL		; save time
	PUSH	DE
	PUSH	BC
	PUSH	AF
	LD	HL,(1)		; this is SOME bios address..
	LD	DE,57H		; ptr to "NZ-COM" eyecatcher
	ADD	HL,DE		; look for expected eyecatcher here
	LD	DE,NZCEYE	; ptr to another copy of it
	LD	B,6		; length

NZCKLOOP:
	LD	A,(DE)		; get a char
	CP	(HL)		; compare to char at hl
	JR	NZ,NONZC	; no nz-com
	INC	HL		; bump ptr
	INC	DE		; bump ptr
	DEC	B		; decrement length
	JR	NZ,NZCKLOOP	; repeat if apropos

	LD	HL,(1)		; pick up bios pointer again
	LD	DE,84H		; offset to BIOS page address in
				; first entry in NZ-COM's 
				; second-level jump table
	ADD	HL,DE
	LD	A,(HL)		; get bios page
	JR	RETBIOS		; and return bios addr in biosaddr

NONZC:
	LD	A,(2)		; get original page number

RETBIOS:
	LD	(BIOSADDR+1),A	; save page
	POP	AF		; restore regs
	POP	BC
	POP	DE
	POP	HL
	RET

NZCEYE:
	DB	'NZ-COM'	; eyecather to match

BIOSADDR:
	DW	3		; just need to set page

;------------------------------------------------------------

; End of AMPRO MEX modem overlay

;------------------------------------------------------------
 
	END