disk.cpp

XOSL 多操作系统管理工具 源代码 多系统引导工具

/*
 * Extended Operating System Loader (XOSL)
 * Copyright (c) 1999 by Geurt Vos
 *
 * This code is distributed under GNU General Public License (GPL)
 *
 * The full text of the license can be found in the GPL.TXT file,
 * or at http://www.gnu.org
 */

#include <disk.h>
#include <mem.h>
#include <transfer.h>

CDisk::CDisk()
{
}

CDisk::~CDisk()
{
}

int CDisk::DriveCount(int Fixed)
{
	if (Fixed)
		return DiskAccess.DriveCount(0x80);
	return DiskAccess.DriveCount(0x00);
}

int CDisk::Map(int Drive, long StartSector)
{
	int Status;

	this->Drive = Drive;
	this->StartSector = StartSector;
	if (Drive >= 0x80 && DiskAccess.LBAAccessAvail(Drive) == 0)
		UseLBA = 1;
	else {
		if (DiskAccess.GetDriveInfo(Drive,DrvHeadCount,DrvSectorCount) == -1) {
			DiskMapped = 0;
			return -1;
		}
		UseLBA = 0;
	}
	DiskMapped = 1;
	return 0;
}

int CDisk::Read(long Sector, void *Buffer, int Count)
{
	int Status;

	if (!DiskMapped)
		return -1;
	Status = Transfer(DISK_READ,Sector,Scratchpad,Count);
	DiskAccess.CopyFromScratchpad(Buffer,Count);
	return Status;
}


int CDisk::Write(long Sector, const void *Buffer, int Count)
{
	if (!DiskMapped)
		return -1;
	DiskAccess.CopyToScratchpad(Buffer,Count);
	return Transfer(DISK_WRITE,Sector,Scratchpad,Count);
}

int CDisk::Verify(long Sector, int Count)
{
	if (!DiskMapped)
		return -1;
	return Transfer(DISK_VERIFY,Sector,NULL,Count);
}

int CDisk::Transfer(int Action, long Sector, void *Buffer, int Count)
{
	TLBAPacket LBAPacket;
	unsigned short SectCyl, DrvHead;

	if (UseLBA) {
		LBAPacket.PacketSize = 0x0010;
		LBAPacket.SectorCount = Count;
		LBAPacket.TransferBuffer = Buffer;
		LBAPacket.SectorLow = Sector + StartSector;
		LBAPacket.SectorHigh = 0;
		return DiskAccess.LBATransfer(Action,Drive,LBAPacket);
	}
	Sector2CHS(Sector,SectCyl,DrvHead);
	return DiskAccess.Transfer(Action,SectCyl,DrvHead,Buffer,Count);
}


void CDisk::Sector2CHS(long RSector, unsigned short &SectCyl, unsigned short &DrvHead)
{
	int Cylinder;
	int Sector;
	int Head;

	RSector += StartSector;

	Sector = RSector % DrvSectorCount + 1;
	RSector /= DrvSectorCount;
	Head = RSector % DrvHeadCount;
	Cylinder = RSector / DrvHeadCount;

	DrvHead = Drive | (Head << 8);
	SectCyl = Sector | ((Cylinder & 0xff) << 8) | ((Cylinder >> 8) << 6);
}