/* 
	FIPS - the First nondestructive Interactive Partition Splitting program 
 
	Module disk_io.cpp 
 
	RCS - Header: 
	$Header: c:/daten/fips/source/main/RCS/disk_io.cpp 1.1 1994/05/25 22:19:43 schaefer Exp schaefer $ 
 
	Copyright (C) 1993 Arno Schaefer 
 
	This program is free software; you can redistribute it and/or modify 
	it under the terms of the GNU General Public License as published by 
	the Free Software Foundation; either version 2 of the License, or 
	(at your option) any later version. 
 
	This program is distributed in the hope that it will be useful, 
	but WITHOUT ANY WARRANTY; without even the implied warranty of 
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
	GNU General Public License for more details. 
 
	You should have received a copy of the GNU General Public License 
	along with this program; if not, write to the Free Software 
	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 
 
 
	Report problems and direct all questions to: 
 
	schaefer@rbg.informatik.th-darmstadt.de 
*/ 
 
#include "disk_io.h" 
#include <dos.h> 
#include <bios.h> 
 
#define DISK_INT 0x13 
 
#define RESET_DISK 0 
#define READ_SECTOR 2 
#define WRITE_SECTOR 3 
#define VERIFY_SECTOR 4 
#define GET_DRIVE_PARAMS 8 
#define GET_DISK_TYPE 0x15 
 
/* ----------------------------------------------------------------------- */ 
/* Bios call to get the number of drives attached                          */ 
/* ----------------------------------------------------------------------- */ 
 
int get_no_of_drives (void) 
{ 
	union REGS regs; 
 
	regs.h.ah = GET_DRIVE_PARAMS; 
	regs.h.dl = 0x80; 
	int86 (DISK_INT,&regs,&regs); 
	if (regs.h.ah != 0) return (1); // will be checked again 
	return (regs.h.dl); 
} 
 
/* ----------------------------------------------------------------------- */ 
/* Calculates physical sector number (Head, Cylinder, Sector).             */ 
/* Log_sector is absolute logical sector number (0 = master boot record).  */ 
/* ----------------------------------------------------------------------- */ 
 
physical_sector_no::physical_sector_no (dword log_sector,const drive_geometry &geometry) 
{ 
	cylinder = log_sector / (geometry.heads * geometry.sectors); 
	head = (log_sector - (cylinder * geometry.heads * geometry.sectors)) / geometry.sectors; 
	sector = log_sector - (cylinder * geometry.heads * geometry.sectors) - (head * geometry.sectors) + 1; 
} 
 
/* ----------------------------------------------------------------------- */ 
/* Bios call get_drive_geometry, returns error status in var errorcode     */ 
/* ----------------------------------------------------------------------- */ 
 
void physical_drive::get_geometry (void) 
{ 
	union REGS regs; 
 
	regs.h.ah = GET_DRIVE_PARAMS; 
	regs.h.dl = number; 
	int86 (DISK_INT,&regs,&regs); 
	if ((errorcode = regs.h.ah) != 0) return; 
	geometry.heads = (dword) regs.h.dh + 1; 
	geometry.sectors = (dword) regs.h.cl & 0x3f; 
	geometry.cylinders = ((dword) regs.h.ch | (((dword) regs.h.cl << 2) & 0x300)) + 1; 
} 
 
/* ----------------------------------------------------------------------- */ 
/* Bios call reset_drive, returns error status in var errorcode            */ 
/* ----------------------------------------------------------------------- */ 
 
void physical_drive::reset (void) 
{ 
	union REGS regs; 
 
	regs.h.ah = RESET_DISK; 
	regs.h.dl = number; 
	int86 (DISK_INT,&regs,&regs); 
	errorcode = regs.h.ah; 
} 
 
/* ----------------------------------------------------------------------- */ 
/* Initialization physical_drive, requires drive number.                   */ 
/* Calls get_drive_geometry, errorcode contains return status              */ 
/* ----------------------------------------------------------------------- */ 
 
physical_drive::physical_drive (int number) 
{ 
	physical_drive::number = number; 
	get_geometry (); 
}; 
 
/* ----------------------------------------------------------------------- */ 
/* Initialization physical_drive with physical_drive object                */ 
/* ----------------------------------------------------------------------- */ 
 
physical_drive::physical_drive (physical_drive &pd) 
{ 
	number = pd.number; 
	errorcode = pd.errorcode; 
	geometry = pd.geometry; 
} 
 
/* ----------------------------------------------------------------------- */ 
/* Overloaded assignment operator for physical drive                       */ 
/* ----------------------------------------------------------------------- */ 
 
void physical_drive::operator= (physical_drive &pd) 
{ 
	number = pd.number; 
	errorcode = pd.errorcode; 
	geometry = pd.geometry; 
} 
 
/* ----------------------------------------------------------------------- */ 
/* Read sector                                                             */ 
/* ----------------------------------------------------------------------- */ 
 
int sector::read (physical_drive *drive,dword sector) 
{ 
	physical_sector_no p (sector,drive->geometry); 
 
	boolean done=false; 
	for (int i=0;i<3;i++) 
	{ 
		if (!biosdisk (READ_SECTOR,drive->number,p.head,p.cylinder,p.sector,1,data)) 
		{ 
			done=true; 
			break; 
		} 
		drive->reset (); 
	} 
	if (!done) return (-1); 
	return 0; 
} 
 
/* ----------------------------------------------------------------------- */ 
/* Verify sector CRC                                                       */ 
/* ----------------------------------------------------------------------- */ 
 
int verify_sector (physical_drive *drive,dword head,dword cylinder,dword sector,byte *buffer) 
{ 
	if (biosdisk (VERIFY_SECTOR,drive->number,head,cylinder,sector,1,buffer)) return (-1); 
	return 0; 
} 
 
/* ----------------------------------------------------------------------- */ 
/* Write sector with verify                                                */ 
/* ----------------------------------------------------------------------- */ 
 
int sector::write (physical_drive *drive,dword sector) 
{ 
	physical_sector_no p (sector,drive->geometry); 
 
	boolean done=false; 
	for (int i=0;i<3;i++) 
	{ 
		if (!biosdisk (WRITE_SECTOR,drive->number,p.head,p.cylinder,p.sector,1,data)) 
		{ 
			done=true; 
			break; 
		} 
		drive->reset (); 
	} 
	if (!done) return (-1); 
	return (verify_sector (drive,p.head,p.cylinder,p.sector,data)); 
} 
 
/* ----------------------------------------------------------------------- */ 
/* Bios call get_disk_type - returns 0 if drive not present.               */ 
/* Valid drive numbers: 0 - 255, result: 1 - floppy without disk change    */ 
/* detection, 2 - floppy with disk change detection, 3 - harddisk          */ 
/* ----------------------------------------------------------------------- */ 
 
int get_disk_type (int drive_number) 
{ 
	union REGS regs; 
 
	regs.h.ah = GET_DISK_TYPE; 
	regs.h.dl = drive_number; 
	int86 (DISK_INT,&regs,&regs); 
	if (regs.x.cflag) return 0; 
	return (regs.h.ah);                     // disk type 
}