RomWBW/Source/HBIOS/rf.asm

;
;==================================================================================================
;   RAM FLOPPY DISK DRIVER
;==================================================================================================
;
;
;
RF_U0IO		.EQU	$A0
RF_U1IO		.EQU	$A4
;
; IO PORT OFFSETS
;
RF_DAT		.EQU	0
RF_AL		.EQU	1
RF_AH		.EQU	2
RF_ST		.EQU	3
;
;
;
RF_INIT:
	CALL	NEWLINE			; FORMATTING
	PRTS("RF: UNITS=$")
	LD	A,RFCNT
	CALL	PRTDECB
;
; SETUP THE DISPATCH TABLE ENTRIES
;
;
; SETUP THE DISPATCH TABLE ENTRIES
;
	LD	B,RFCNT		; LOOP CONTROL
	LD	C,0		; PHYSICAL UNIT INDEX
RF_INIT0:
	PUSH	BC		; SAVE LOOP CONTROL
	LD	B,C		; PHYSICAL UNIT
	LD	C,DIODEV_RF	; DEVICE TYPE
	LD	DE,0		; UNIT DATA BLOB ADDRESS
	CALL	DIO_ADDENT	; ADD ENTRY, BC IS NOT DESTROYED
	POP	BC		; RESTORE LOOP CONTROL
	INC	C		; NEXT PHYSICAL UNIT
	DJNZ	RF_INIT0	; LOOP UNTIL DONE
;
	XOR	A		; INIT SUCCEEDED
	RET			; RETURN
;
;
;
RF_DISPATCH:
	; VERIFY AND SAVE THE TARGET DEVICE/UNIT LOCALLY IN DRIVER
	LD	A,C		; DEVICE/UNIT FROM C
	AND	$0F		; ISOLATE UNIT NUM
	CP	2		; CHECK FOR MAX UNIT EXCEEDED
	LD	(RF_UNIT),A	; SAVE IT
	CALL	NC,PANIC	; PANIC IF TOO HIGH
;
	; DISPATCH ACCORDING TO DISK SUB-FUNCTION
	LD	A,B		; GET REQUESTED FUNCTION
	AND	$0F		; ISOLATE SUB-FUNCTION
	JP	Z,RF_STATUS	; SUB-FUNC 0: STATUS
	DEC	A
	JP	Z,RF_RESET	; SUB-FUNC 1: RESET
	DEC	A
	JP	Z,RF_SEEK	; SUB-FUNC 2: SEEK
	DEC	A
	JP	Z,RF_READ	; SUB-FUNC 3: READ SECTORS
	DEC	A
	JP	Z,RF_WRITE	; SUB-FUNC 4: WRITE SECTORS
	DEC	A
	JP	Z,RF_VERIFY	; SUB-FUNC 5: VERIFY SECTORS
	DEC	A
	JP	Z,RF_FORMAT	; SUB-FUNC 6: FORMAT TRACK
	DEC	A
	JP	Z,RF_DEVICE	; SUB-FUNC 7: DEVICE REPORT
	DEC	A
	JP	Z,RF_MEDIA	; SUB-FUNC 8: MEDIA REPORT
	DEC	A
	JP	Z,RF_DEFMED	; SUB-FUNC 9: DEFINE MEDIA
	DEC	A
	JP	Z,RF_CAP	; SUB-FUNC 10: REPORT CAPACITY
	DEC	A
	JP	Z,RF_GEOM	; SUB-FUNC 11: REPORT GEOMETRY
;
RF_VERIFY:
RF_FORMAT:
RF_DEFMED:
	CALL	PANIC		; INVALID SUB-FUNCTION
;
;
;
RF_STATUS:
	XOR	A		; STATUS ALWAYS OK
	RET
;
;
;
RF_RESET:
	XOR	A		; ALWAYS OK
	RET
;
;
;
RF_CAP:
	LD	A,C		; DEVICE/UNIT IS IN C
	AND	$0F		; ISOLATE UNIT NUM
	CP	RFCNT		; CHECK FOR MAX UNIT EXCEEDED
	CALL	NC,PANIC	; PANIC IF TOO HIGH
;
	LD	DE,0
	LD	HL,$2000	; 8192 BLOCKS OF 512 BYTES
	XOR	A
	RET
;
;
;
RF_GEOM:
	; FOR LBA, WE SIMULATE CHS ACCESS USING 16 HEADS AND 16 SECTORS
	; RETURN HS:CC -> DE:HL, SET HIGH BIT OF D TO INDICATE LBA CAPABLE
	CALL	RF_CAP			; GET TOTAL BLOCKS IN DE:HL, BLOCK SIZE TO BC
	LD	L,H			; DIVIDE BY 256 FOR # TRACKS
	LD	H,E			; ... HIGH BYTE DISCARDED, RESULT IN HL
	LD	D,16 | $80		; HEADS / CYL = 16, SET LBA CAPABILITY BIT
	LD	E,16			; SECTORS / TRACK = 16
	XOR	A			; SIGNAL SUCCESS
	RET
;
;
;
RF_DEVICE:
	LD	D,DIODEV_RF	; D := DEVICE TYPE
	LD	E,C		; E := PHYSICAL UNIT
	LD	C,%00110000	; C := ATTRIBUTES, NON-REMOVALBE RAM FLOPPY
	XOR	A		; SIGNAL SUCCESS
	RET
;
;
;
RF_MEDIA:
		LD	E,MID_RF	; RAM FLOPPY MEDIA
	LD	D,0			; D:0=0 MEANS NO MEDIA CHANGE
	XOR	A			; SIGNAL SUCCESS
	RET
;	
;	
;	
RF_SEEK:	
	BIT	7,D			; CHECK FOR LBA FLAG
	CALL	Z,HB_CHS2LBA		; CLEAR MEANS CHS, CONVERT TO LBA
	RES	7,D			; CLEAR FLAG REGARDLESS (DOES NO HARM IF ALREADY LBA)
	LD	BC,HSTLBA		; POINT TO LBA STORAGE
	CALL	ST32			; SAVE LBA ADDRESS
	XOR	A			; SIGNAL SUCCESS
	RET				; AND RETURN
;
;
;
RF_READ:
	LD	(RF_DSKBUF),HL	; SAVE DISK BUFFER ADDRESS
	CALL	RF_SETIO
	CALL	RF_SETADR
	LD	HL,(RF_DSKBUF)
	LD	B,0
	LD	A,(RF_IO)
	OR	RF_DAT
	LD	C,A
	INIR
	INIR
	XOR	A
	RET
;
;
;
RF_WRITE:
	LD	(RF_DSKBUF),HL	; SAVE DISK BUFFER ADDRESS
	CALL	RF_SETIO
	LD	A,(RF_IO)
	OR	RF_ST
	LD	C,A
	IN	A,(C)
	BIT	0,A			; CHECK WRITE PROTECT
	LD	A,1			; PREPARE TO RETURN FALSE (ERROR)
	RET	NZ			; WRITE PROTECTED!
	CALL	RF_SETADR
	LD	HL,(RF_DSKBUF)
	LD	B,0
	LD	A,(RF_IO)
	OR	RF_DAT
	LD	C,A
	OTIR
	OTIR
	XOR	A
	RET
;
;
;
RF_SETIO:
	LD	A,(RF_UNIT)	; GET DEVICE/UNIT
	AND	$0F		; ISOLATE UNIT NUM
	JR	NZ,RF_SETIO1
	LD	A,RF_U0IO
	JR	RF_SETIO3
RF_SETIO1:
	DEC	A
	JR	NZ,RF_SETIO2
	LD	A,RF_U1IO
	JR	RF_SETIO3
RF_SETIO2:
	CALL	PANIC		; INVALID UNIT
RF_SETIO3:
	LD	(RF_IO),A
	RET
;
;
;
RF_SETADR:
	LD	A,(RF_IO)
	OR	RF_AL
	LD	C,A
	LD	A,(HSTLBALO)
	OUT	(C),A
	LD	A,(HSTLBALO+1)
	INC	C
	OUT	(C),A
	RET
;
;
;
RF_IO	.DB	0
;
RF_UNIT		.DB	0
RF_DSKBUF	.DW	0