;*; Updated on 06-Dec-91 at 9:16 AM by Michele Tonti; edit time: 0:00:12
;*************************** AMUS Program Label ******************************
; Filename: DSKFRE.M68                                      Date: 12/6/91
; Category: SBR          Hash Code: 561-445-106-040      Version:                
; Initials: KUNI/AM      Name: RENE S. HOLLAN
; Company: UDISCO LTD.                             Telephone #: 5144818107
; Related Files: DSKFRE.SBR,DSKFRE.DOC,DSKFRE.BAS,DSKFRE.RUN,DSKFRE.LIT
; Min. Op. Sys.:                               Expertise Level: 
; Special: 
; Description: Returns the largest contiguous block free and the total number 
; of blocks free on a specified device.
; 
;*****************************************************************************
;************************************************************************
;									*
;				DSKFRE BASIC SUBROUTINE			*
;									*
;************************************************************************
;
;                                   NOTICE
;
;All    rights   reserved.  This software is the property of UDISCO LTD.  and
;the material contained herein is  the   proprietary   property   and   trade
;secrets    of    UDISCO  LTD.,  embodying  substantial  creative efforts and
;confidential information, ideas and expressions, no part of  which  may   be
;reproduced   or  transmitted  in  any  form  or  by  any  means, electronic,
;mechanical,  or  otherwise,  including  photocopying  or  input  into    any
;information   storage  or  retrieval  system  without  the  express  written
;permission of UDISCO LTD.
;
;Permission to copy and use is granted to AMUS members for non commercial 
;purposes only.
;
;	Author:		Rene S. Hollan
;	Date Written:	June 3, 1989
;
;	COPYRIGHT (C) 1989 - UDISCO LTD.
;
;Edit History
;
;[100]	3 July 89
;	Coding starts. /RSH
;
;	Usage:	XCALL DSKFRE,<device spec.>,<contig>,<total>
;
;	Where	<device spec.> is device specification (i.e. DSK0:),
;
;		<contig> receives size of largest contigous block,
;
;		<total> receives total number of blocks free.
;
;		<contig> and <total> must be mapped as floating point
;	variables, i.e.:
;
;		MAP1 contig,F,6
;		MAP1 total,F,6
;
;		If an error occurs (bad device spec., etc.) contig is set to
;	0 and the file system error code is returned in total.
;
;	Note that the device driver for the specified device must be loaded
; into memory and that there must be sufficient memory available in the
; BASIC impure area to hold a 24 byte result table (from DSKFRE), a DDB, 
; and a 512 byte disk buffer.
;

	SEARCH	SYS
	SEARCH	SYSSYM

	OBJNAM	0,0,[SBR]

VMAJOR	=	1			; major version
VMINOR	=	0			; minor version
VSUB	=	0			; sub version
VEDIT	=	100.			; edit level
VWHO	=	0			; patch level

; On entry A3 points to the following parameter block

.OFINI					; BASIC calling parameter area
.OFDEF	Bas.No,2				;    number of parameters (3)
.OFDEF	Bas.T1,2				;    type code (string)
.OFDEF	Bas.A1,4				;    variable address
.OFDEF	Bas.L1,4				;    variable length
.OFDEF	Bas.T2,2				;    type code (string)
.OFDEF	Bas.A2,4				;    variable address
.OFDEF	Bas.L2,4				;    variable length
.OFDEF	Bas.T3,2				;    type code (string)
.OFDEF	Bas.A3,4				;    variable address
.OFDEF	Bas.L3,4				;    variable length
.OFSIZ	Bas.Sz				; parameter area size

DSKFRE:	PHDR	-1,PV$RSM,PH$REU!PH$REE  ; program header
	MOV	Bas.A1(A3),A2		; A2 -> device name
	MOV	A4,A5			; A5 -> device table
	LEA	A4,DF.SIZ(A4)		; adjust for device table size
	ORB	#D$BYP+D$ERC,D.FLG(A4)	; bypass error messages
	FSPEC	@A4			; FSPEC the device name into imp. area
	BNE	ERR			; error

	MOV	A4,D.BUF(A4)		; D.BUF --> base of DDB
	ADD	#D.DDB,D.BUF(A4)	; D.BUF --> buffer area
	MOV	#512.,D.SIZ(A4)		; set buffer size
	CLR	D.DVR(A4)		; no driver
	ORB	#D$INI,D.FLG(A4)	; set buffer inited flag
; WARNING!!! - DEVICE DRIVER MUST BE IN MEMORY OR ALL THIS WILL BLOW UP IN
;	       YOUR FACE!
	DSKFRE	@A4,@A5			; get free space on device
	BEQ	OK			; no error

ERR:	CLR	D1			; clear contiguous blocks
	MOV	D1,DF.HOL(A5)		; ...
	MOVB	D.ERR(A4),D1		; set error code in total blocks
	MOV	D1,DF.FRE(A5)		; ...

OK:
	MOV	Bas.A2(A3),A1		; A1 -> contiguous space result
	FLTOF	DF.HOL(A5),@A1		; return contiguous space
	MOV	Bas.A3(A3),A1		; A1 -> total space result
	FLTOF	DF.FRE(A5),@A1		; return total space

	RTN				; and return

	END

.