PIO0A	.EQU	; ECB-ZP
PIO0B	.EQU	; ECB-ZP
PIO1A	.EQU	; ECB-ZP
PIO1B	.EQU	; ECB-ZP

PIO2A	.EQU	; ECB-4PIO
PIO2B	.EQU	; ECB-4PIO
PIO3A	.EQU	; ECB-4PIO
PIO3B	.EQU	; ECB-4PIO
PIO4A	.EQU	; ECB-4PIO
PIO4B	.EQU	; ECB-4PIO
PIO5A	.EQU	; ECB-4PIO
PIO5B	.EQU	; ECB-4PIO

PIO_Input	.EQU	$0000
PIO_Output	.EQU	$0001
PIO_BiDir	.Equ	$0002

DEFPIOCFGA	.EQU	$8000 + PIO_Input
DEFPIOCFGB	.EQU	$8000 + PIO_Output
DEFPIOCFGX	.EQU	$8000 + PIO_BiDir

PIO_NONE	.EQU	0
PIO_ZPIO	.EQU	1
PIO_8255	.EQU	2
;
PIO_PREINIT:
;
; SETUP THE DISPATCH TABLE ENTRIES
;
	LD	B,PIO_CNT		; LOOP CONTROL
	LD	C,0				; PHYSICAL UNIT INDEX
	XOR	A				; ZERO TO ACCUM
	LD	(PIO_DEV),A		; CURRENT DEVICE NUMBER
PIO_PREINIT0:	
	PUSH	BC			; SAVE LOOP CONTROL
	LD	A,C				; PHYSICAL UNIT TO A
	RLCA				; MULTIPLY BY CFG TABLE ENTRY SIZE (8 BYTES)
	RLCA				; ...
	RLCA				; ... TO GET OFFSET INTO CFG TABLE
	LD	HL,PIO_CFG		; POINT TO START OF CFG TABLE
	CALL	ADDHLA		; HL := ENTRY ADDRESS
	PUSH	HL			; SAVE IT
	PUSH	HL			; COPY CFG DATA PTR
	POP	IY				; ... TO IY
	CALL	PIO_INITUNIT		; HAND OFF TO GENERIC INIT CODE
	POP	DE				; GET ENTRY ADDRESS BACK, BUT PUT IN DE
	POP	BC				; RESTORE LOOP CONTROL
;
	LD	A,(IY+1)		; GET THE PIO TYPE DETECTED
	OR	A				; SET FLAGS
	JR	Z,PIO_PREINIT2		; SKIP IT IF NOTHING FOUND
;	
	PUSH	BC			; SAVE LOOP CONTROL
	LD	BC,PIO_FNTBL		; BC := FUNCTION TABLE ADDRESS
	CALL	NZ,CIO_ADDENT		; ADD ENTRY IF PIO FOUND, BC:DE
	POP	BC			; RESTORE LOOP CONTROL
;
PIO_PREINIT2:	
	INC	C			; NEXT PHYSICAL UNIT
	DJNZ	PIO_PREINIT0		; LOOP UNTIL DONE
;
;#IF (INTMODE == 1)
;	; ADD IM1 INT CALL LIST ENTRY IF APPROPRIATE
;	LD	A,(SIO_DEV)		; GET NEXT DEVICE NUM
;	OR	A			; SET FLAGS
;	JR	Z,PIO_PREINIT3		; IF ZERO, NO SIO DEVICES
;	LD	HL,PIO_INT		; GET INT VECTOR
;	CALL	HB_ADDIM1		; ADD TO IM1 CALL LIST
;#ENDIF
;
;#IF (INTMODE == 2)
;	; SETUP SIO INTERRUPT VECTOR IN IVT
;	LD	HL,INT_PIO
;	LD	(HBX_IVT + IVT_SER0),HL
;#ENDIF
;
PIO_PREINIT3:
	XOR	A			; SIGNAL SUCCESS
	RET				; AND RETURN
;
PIO_INITUNIT:
	XOR	A			; SIGNAL SUCCESS
	RET				; AND RETURN
;
PIO_INIT:
	LD	B,PIO_CNT		; COUNT OF POSSIBLE SIO UNITS
	LD	C,0			; INDEX INTO SIO CONFIG TABLE
PIO_INIT1:
	PUSH	BC			; SAVE LOOP CONTROL
	
	LD	A,C			; PHYSICAL UNIT TO A
	RLCA				; MULTIPLY BY CFG TABLE ENTRY SIZE (8 BYTES)
	RLCA				; ...
	RLCA				; ... TO GET OFFSET INTO CFG TABLE
	LD	HL,PIO_CFG		; POINT TO START OF CFG TABLE
	CALL	ADDHLA			; HL := ENTRY ADDRESS
	PUSH	HL			; COPY CFG DATA PTR
	POP	IY			; ... TO IY
	
	LD	A,(IY+1)		; GET PIO TYPE
	OR	A			; SET FLAGS
	CALL	NZ,PIO_PRTCFG		; PRINT IF NOT ZERO
	
	POP	BC			; RESTORE LOOP CONTROL
	INC	C			; NEXT UNIT
	DJNZ	PIO_INIT1		; LOOP TILL DONE
;
	XOR	A			; SIGNAL SUCCESS
	RET				; DONE

;
PIO_LPT:
	IN		A,($F6)		; get device status
	AND		$20			; device ready?
	JR		Z,PIO_LPT	; no, busy wait
	IN		A,($F5)			; get transmit buffer register status ready?
	AND		$20			; ready?
	JR		Z,PIO_LPT	; no, busy wait
	LD		A,C			; ready, char A for output through data port
	OUT		($F0),A		; output char
	RET
;
; PIO PORT TABLE
;
PIO_CFG:
	; PIO CHANNEL A
	.DB	0				; DEVICE NUMBER (SET DURING INIT)
	.DB	PIO_ZPIO			; PIO TYPE (SET DURING INIT)
	.DB	0				; PIO CHANNEL (A)
	.DB	PIOBASE+2		; BASE PORT (CMD PORT)
	.DW	DEFPIOCFGA		; LINE CONFIGURATION
	.DW	SIOA_RCVBUF		; POINTER TO RCV BUFFER STRUCT
;
	; PIO CHANNEL B
	.DB	1				; DEVICE NUMBER (SET DURING INIT)
	.DB	PIO_ZPIO			; PIO TYPE (SET DURING INIT)
	.DB	1				; PIO CHANNEL (B)
	.DB	PIOBASE+3		; BASE PORT (CMD PORT)
	.DW	DEFPIOCFGB		; LINE CONFIGURATION
	.DW	SIOB_RCVBUF		; POINTER TO RCV BUFFER STRUCT
;	
	; PIO CHANNEL A
	.DB	2				; DEVICE NUMBER (SET DURING INIT)
	.DB	PIO_ZPIO			; PIO TYPE (SET DURING INIT)
	.DB	0				; PIO CHANNEL (A)
	.DB	PIOBASE+6		; BASE PORT (CMD PORT)
	.DW	DEFPIOCFGA		; LINE CONFIGURATION
	.DW	SIOA_RCVBUF		; POINTER TO RCV BUFFER STRUCT
;
	; PIO CHANNEL B
	.DB	3				; DEVICE NUMBER (SET DURING INIT)
	.DB	PIO_ZPIO		; PIO TYPE (SET DURING INIT)
	.DB	1				; PIO CHANNEL (B)
	.DB	PIOBASE+7		; BASE PORT (CMD PORT)
	.DW	DEFPIOCFGB		; LINE CONFIGURATION
	.DW	SIOB_RCVBUF		; POINTER TO RCV BUFFER STRUCT
	; PIO CHANNEL A
	.DB	4				; DEVICE NUMBER (SET DURING INIT)
	.DB	PIO_ZPIO		; PIO TYPE (SET DURING INIT)
	.DB	0				; PIO CHANNEL (A)
	.DB	4PIOBASE+2		; BASE PORT (CMD PORT)
	.DW	DEFPIOCFGX		; LINE CONFIGURATION
	.DW	SIOA_RCVBUF		; POINTER TO RCV BUFFER STRUCT
;
	; PIO CHANNEL B
	.DB	5				; DEVICE NUMBER (SET DURING INIT)
	.DB	PIO_ZPIO		; PIO TYPE (SET DURING INIT)
	.DB	1				; PIO CHANNEL (B)
	.DB	4PIOBASE+3		; BASE PORT (CMD PORT)
	.DW	DEFPIOCFGB		; LINE CONFIGURATION
	.DW	SIOB_RCVBUF		; POINTER TO RCV BUFFER STRUCT
;	
	; PIO CHANNEL A
	.DB	6				; DEVICE NUMBER (SET DURING INIT)
	.DB	PIO_ZPIO		; PIO TYPE (SET DURING INIT)
	.DB	0				; PIO CHANNEL (A)
	.DB	4PIOBASE+6		; BASE PORT (CMD PORT)
	.DW	DEFPIOCFGA		; LINE CONFIGURATION
	.DW	SIOA_RCVBUF		; POINTER TO RCV BUFFER STRUCT
;
	; PIO CHANNEL B
	.DB	7				; DEVICE NUMBER (SET DURING INIT)
	.DB	PIO_ZPIO		; PIO TYPE (SET DURING INIT)
	.DB	1				; PIO CHANNEL (B)
	.DB	4PIOBASE+7		; BASE PORT (CMD PORT)
	.DW	DEFPIOCFGB		; LINE CONFIGURATION
	.DW	SIOB_RCVBUF		; POINTER TO RCV BUFFER STRUCT
;
	; PIO CHANNEL A
	.DB	8				; DEVICE NUMBER (SET DURING INIT)
	.DB	PIO_ZPIO		; PIO TYPE (SET DURING INIT)
	.DB	0				; PIO CHANNEL (A)
	.DB	4PIOBASE+10		; BASE PORT (CMD PORT)
	.DW	DEFPIOCFGA		; LINE CONFIGURATION
	.DW	SIOA_RCVBUF		; POINTER TO RCV BUFFER STRUCT
;
	; PIO CHANNEL B
	.DB	9				; DEVICE NUMBER (SET DURING INIT)
	.DB	PIO_ZPIO		; PIO TYPE (SET DURING INIT)
	.DB	1				; PIO CHANNEL (B)
	.DB	4PIOBASE+11		; BASE PORT (CMD PORT)
	.DW	DEFPIOCFGB		; LINE CONFIGURATION
	.DW	SIOB_RCVBUF		; POINTER TO RCV BUFFER STRUCT
;	
	; PIO CHANNEL A
	.DB	10				; DEVICE NUMBER (SET DURING INIT)
	.DB	PIO_ZPIO		; PIO TYPE (SET DURING INIT)
	.DB	0				; PIO CHANNEL (A)
	.DB	4PIOBASE+14		; BASE PORT (CMD PORT)
	.DW	DEFPIOCFGA		; LINE CONFIGURATION
	.DW	SIOA_RCVBUF		; POINTER TO RCV BUFFER STRUCT
;
	; PIO CHANNEL B
	.DB	11				; DEVICE NUMBER (SET DURING INIT)
	.DB	PIO_ZPIO		; PIO TYPE (SET DURING INIT)
	.DB	1				; PIO CHANNEL (B)
	.DB	4PIOBASE+15		; BASE PORT (CMD PORT)
	.DW	DEFPIOCFGB		; LINE CONFIGURATION
	.DW	SIOB_RCVBUF		; POINTER TO RCV BUFFER STRUCT
;	
	; PIO CHANNEL A
	.DB	12				; DEVICE NUMBER (SET DURING INIT)
	.DB	PIO_ZPIO		; PIO TYPE (SET DURING INIT)
	.DB	0				; PIO CHANNEL (A)
	.DB	4PIOBASE+14		; BASE PORT (CMD PORT)
	.DW	DEFPIOCFGA		; LINE CONFIGURATION
	.DW	SIOA_RCVBUF		; POINTER TO RCV BUFFER STRUCT
;
	; PIO CHANNEL B
	.DB	13				; DEVICE NUMBER (SET DURING INIT)
	.DB	PIO_8255		; PIO TYPE (SET DURING INIT)
	.DB	1				; PIO CHANNEL (B)
	.DB	4PIOBASE+15		; BASE PORT (CMD PORT)
	.DW	DEFPIOCFGB		; LINE CONFIGURATION
	.DW	SIOB_RCVBUF		; POINTER TO RCV BUFFER STRUCT
	;
;
PIO_CNT	.EQU	($ - PIO_CFG) / 8	
;
; DRIVER FUNCTION TABLE
;
PIO_FNTBL:
	.DW	PIO_IN
	.DW	PIO_OUT
	.DW	PIO_IST
	.DW	PIO_OST
	.DW	PIO_INITDEV
	.DW	PIO_QUERY
	.DW	PIO_DEVICE
#IF (($ - PIO_FNTBL) != (CIO_FNCNT * 2))
	.ECHO	"*** INVALID SIO FUNCTION TABLE ***\n"
#ENDIF
;
PIO_OUT:
	XOR	A			; SIGNAL SUCCESS
	RET
;	
PIO_IN:
	XOR	A			; SIGNAL SUCCESS
	RET	
;	
PIO_IST:
	RET	
;	
PIO_OST:
	RET	
;
; PIO_INITDEV - Configure device.
; If DE = FFFF then extract the configuratio information from the table of devices and program the device using those settings.
; Otherwise use the configuration information in DE to program those settings and save them in the device table

PIO_INITDEV:
	XOR	A			; SIGNAL SUCCESS
	RET	
;
PIO_QUERY:
	LD	E,(IY+4)	; FIRST CONFIG BYTE TO E
	LD	D,(IY+5)	; SECOND CONFIG BYTE TO D
	XOR	A			; SIGNAL SUCCESS
	RET
;
;
;TTY_DEVICE:
;	LD	D,CIODEV_TERM		; TYPE IS TERMINAL
;	LD	A,(TTY_DEVNUM)		; GET DEVICE NUMBER
;	LD	E,A			; PUT IT IN E
;	LD	A,(TTY_VDAUNIT)		; GET VDA UNIT NUM
;	SET	7,A			; SET BIT 7 TO INDICATE TERMINAL TYPE
;	LD	C,A			; PUT IT IN C
;	XOR	A			; SIGNAL SUCCESS
;	RET
;
;
PIO_DEVICE:
	LD	D,CIODEV_PIO	; D := DEVICE TYPE
	LD	E,(IY)			; E := PHYSICAL UNIT
	LD	A,E
	SET	7,A
	LD	C,A
	XOR	A			; SIGNAL SUCCESS
	RET	
;	
PIO_PRTCFG:
	; ANNOUNCE PORT
	CALL	NEWLINE			; FORMATTING
	PRTS("PIO$")			; FORMATTING
	LD	A,(IY)			; DEVICE NUM
	CALL	PRTDECB			; PRINT DEVICE NUM
	PRTS(": IO=0x$")		; FORMATTING
	LD	A,(IY+3)		; GET BASE PORT
	CALL	PRTHEXBYTE		; PRINT BASE PORT
;
	; PRINT THE PIO TYPE
	CALL	PC_SPACE		; FORMATTING
	LD	A,(IY+1)		; GET PIO TYPE BYTE
	RLCA				; MAKE IT A WORD OFFSET
	LD	HL,PIO_TYPE_MAP		; POINT HL TO TYPE MAP TABLE
	CALL	ADDHLA			; HL := ENTRY
	LD	E,(HL)			; DEREFERENCE
	INC	HL			; ...
	LD	D,(HL)			; ... TO GET STRING POINTER
	CALL	WRITESTR		; PRINT IT
;
	; ALL DONE IF NO PIO WAS DETECTED
	LD	A,(IY+1)		; GET SIO TYPE BYTE
	OR	A			; SET FLAGS
	RET	Z			; IF ZERO, NOT PRESENT
;
	PRTS(" MODE=$")			; FORMATTING
	LD	E,(IY+4)		; LOAD CONFIG
	LD	D,(IY+5)		; ... WORD TO DE
	CALL	PS_PRTPC0		; PRINT CONFIG
;
	XOR	A
	RET
;
; WORKING VARIABLES
;
PIO_DEV		.DB	0		; DEVICE NUM USED DURING INIT
;	
PIO_TYPE_MAP:
		.DW	PIO_STR_NONE
		.DW	PIO_STR_PIO
		.DW PIO_STR_8255

PIO_STR_NONE	.DB	"<NOT PRESENT>$"
PIO_STR_PIO		.DB	"Zilog PIO$"
PIO_STR_8255	.DB "i8255 PIO$"