unit Disk;

INTERFACE
uses Exec;


type
	pDiscResourceUnit = ^tDiscResourceUnit;
	pDiscResource = ^tDiscResource;
	tDiscResource = record
		dr_Library: tLibrary;
		dr_Current: pDiscResourceUnit;
		dr_Flags: byte;
		dr_pad: byte;
		dr_SysLib: pLibrary;
		dr_CiaResource: pLibrary;
		dr_UnitID: array [0..3] of long;
		dr_Waiting: tList;
		dr_DiscBlock: tInterrupt;
		dr_DiscSync: tInterrupt;
		dr_Index: tInterrupt;
		end;

	tDiscResourceUnit = record
		dru_Message: tMessage;
		dru_DiscBlock: tInterrupt;
		dru_DiscSync: tInterrupt;
		dru_Index: tInterrupt;
		end;



var
	DiskBase: pDiscResource;


const
	DRB_ALLOC0 = 0;
	DRB_ALLOC1 = 1;
	DRB_ALLOC2 = 2;
	DRB_ALLOC3 = 3;
	DRF_ALLOC0 = 1;
	DR_ALLOCUNIT = $FFFFFFFA;
	DRF_ALLOC1 = 2;
	DRF_ALLOC2 = 4;
	DR_GETUNITID = $FFFFFFE2;
	DRT_EMPTY = $FFFFFFFF;
	DRF_ALLOC3 = 8;
	DR_LASTCOMM = $FFFFFFE8;
	DR_FREEUNIT = $FFFFFFF4;
	DRB_ACTIVE = 7;
	DSKDMAOFF = $4000;
	DRF_ACTIVE = $80;
	DR_GIVEUNIT = $FFFFFFE8;
	DRT_AMIGA = 0;
	DRT_37422D2S = $55555555;
	DR_GETUNIT = $FFFFFFEE;
	DISKNAME = 'disk.resource';


function AllocUnit (unitNum: longint): boolean;
procedure FreeUnit (unitNum: longint);
function GetUnit (unitPointer: pDiscResourceUnit): pDiscResourceUnit;
procedure GiveUnit;
function GetUnitID (unitNum: longint): longint;


IMPLEMENTATION
function AllocUnit; xassembler;
asm
	move.l	a6,-(sp)
	move.l	8(sp),d0
	move.l	DiskBase,a6
	jsr		-6(a6)
	tst.l	d0
	sne		d0
	neg.b	d0
	move.b	d0,$C(sp)
	move.l	(sp)+,a6
end;

procedure FreeUnit; xassembler;
asm
	move.l	a6,-(sp)
	move.l	8(sp),d0
	move.l	DiskBase,a6
	jsr		-$C(a6)
	move.l	(sp)+,a6
end;

function GetUnit; xassembler;
asm
	move.l	a6,-(sp)
	move.l	8(sp),a1
	move.l	DiskBase,a6
	jsr		-$12(a6)
	move.l	d0,$C(sp)
	move.l	(sp)+,a6
end;

procedure GiveUnit; xassembler;
asm
	move.l	a6,-(sp)
	move.l	DiskBase,a6
	jsr		-$18(a6)
	move.l	(sp)+,a6
end;

function GetUnitID; xassembler;
asm
	move.l	a6,-(sp)
	move.l	8(sp),d0
	move.l	DiskBase,a6
	jsr		-$1E(a6)
	move.l	d0,$C(sp)
	move.l	(sp)+,a6
end;

end.