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ntloader/kern/int13.c
a1ive b923ee83b4
enable IF eflag
2025-02-18 14:45:19 +09:00

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/*
* Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
/**
* @file
*
* INT 13 emulation
*
*/
#include <string.h>
#include <stdio.h>
#include "ntloader.h"
#include "int13.h"
#include "vdisk.h"
#if defined(__i386__) || defined(__x86_64__)
/** Emulated drive number */
static int vdisk_drive;
/**
* Initialise emulation
*
* @ret drive Emulated drive number
*/
int initialise_int13 (void)
{
/* Determine drive number */
vdisk_drive = (0x80 | INT13_DRIVE_COUNT++);
DBG ("Emulating drive %#02x\n", vdisk_drive);
return vdisk_drive;
}
/**
* INT 13, 08 - Get drive parameters
*
* @ret ch Low bits of maximum cylinder number
* @ret cl (bits 7:6) High bits of maximum cylinder number
* @ret cl (bits 5:0) Maximum sector number
* @ret dh Maximum head number
* @ret dl Number of drives
* @ret ah Status code
*/
static void int13_get_parameters (struct bootapp_callback_params *params)
{
unsigned int max_cylinder = (VDISK_CYLINDERS - 1);
unsigned int max_head = (VDISK_HEADS - 1);
unsigned int max_sector = (VDISK_SECTORS_PER_TRACK - 0 /* sic */);
unsigned int num_drives;
unsigned int min_num_drives;
/* Calculate number of drives to report */
num_drives = INT13_DRIVE_COUNT;
min_num_drives = ((vdisk_drive & 0x7f) + 1);
if (num_drives < min_num_drives)
num_drives = min_num_drives;
/* Fill in drive parameters */
params->ch = (max_cylinder & 0xff);
params->cl = (((max_cylinder >> 8) << 6) | max_sector);
params->dh = max_head;
params->dl = num_drives;
DBG2 ("Get parameters: C/H/S = %d/%d/%d, drives = %d\n",
(max_cylinder + 1), (max_head + 1), max_sector, num_drives);
/* Success */
params->ah = 0;
}
/**
* INT 13, 15 - Get disk type
*
* @ret cx:dx Sector count
* @ret ah Type code
*/
static void int13_get_disk_type (struct bootapp_callback_params *params)
{
uint32_t sector_count = VDISK_COUNT;
uint8_t drive_type = INT13_DISK_TYPE_HDD;
/* Fill in disk type */
params->cx = (sector_count >> 16);
params->dx = (sector_count & 0xffff);
params->ah = drive_type;
DBG2 ("Get disk type: sectors = %#08x, type = %d\n",
sector_count, drive_type);
}
/**
* INT 13, 41 - Extensions installation check
*
* @v bx 0x55aa
* @ret bx 0xaa55
* @ret cx Extensions API support bitmap
* @ret ah API version
*/
static void int13_extension_check (struct bootapp_callback_params *params)
{
/* Fill in extension information */
params->bx = 0xaa55;
params->cx = INT13_EXTENSION_LINEAR;
params->ah = INT13_EXTENSION_VER_1_X;
DBG2 ("Extensions installation check\n");
}
/**
* INT 13, 48 - Get extended parameters
*
* @v ds:si Drive parameter table
* @ret ah Status code
*/
static void
int13_get_extended_parameters (struct bootapp_callback_params *params)
{
struct int13_disk_parameters *disk_params;
/* Fill in extended parameters */
disk_params = REAL_PTR (params->ds, params->si);
memset (disk_params, 0, sizeof (*disk_params));
disk_params->bufsize = sizeof (*disk_params);
disk_params->flags = INT13_FL_DMA_TRANSPARENT;
disk_params->cylinders = VDISK_CYLINDERS;
disk_params->heads = VDISK_HEADS;
disk_params->sectors_per_track = VDISK_SECTORS_PER_TRACK;
disk_params->sectors = VDISK_COUNT;
disk_params->sector_size = VDISK_SECTOR_SIZE;
DBG2 ("Get extended parameters: C/H/S = %d/%d/%d, sectors = %#llx "
"(%d bytes)\n", disk_params->cylinders, disk_params->heads,
disk_params->sectors_per_track, disk_params->sectors,
disk_params->sector_size);
/* Success */
params->ah = 0;
}
/**
* INT 13, 42 - Extended read
*
* @v ds:si Disk address packet
* @ret ah Status code
*/
static void int13_extended_read (struct bootapp_callback_params *params)
{
struct int13_disk_address *disk_address;
void *data;
/* Read from emulated disk */
disk_address = REAL_PTR (params->ds, params->si);
data = REAL_PTR (disk_address->buffer.segment,
disk_address->buffer.offset);
vdisk_read (disk_address->lba, disk_address->count, data);
/* Success */
params->ah = 0;
}
/**
* Emulate INT 13 drive
*
* @v params Parameters
*/
void emulate_int13 (struct bootapp_callback_params *params)
{
int command = params->ah;
int drive = params->dl;
int min_num_drives;
unsigned long eflags;
if (drive == vdisk_drive)
{
/* Emulated drive - handle internally */
/* Populate eflags with a sensible starting value */
__asm__ ("pushf\n\t"
"pop %0\n\t"
: "=r" (eflags));
params->eflags = (eflags & ~CF);
/* Handle command */
switch (command)
{
case INT13_GET_PARAMETERS:
int13_get_parameters (params);
break;
case INT13_GET_DISK_TYPE:
int13_get_disk_type (params);
break;
case INT13_EXTENSION_CHECK:
int13_extension_check (params);
break;
case INT13_GET_EXTENDED_PARAMETERS:
int13_get_extended_parameters (params);
break;
case INT13_EXTENDED_READ:
int13_extended_read (params);
break;
default:
DBG ("Unrecognised INT 13,%02x\n", command);
params->eflags |= CF;
break;
}
}
else
{
/* Pass through command to underlying INT 13 */
call_interrupt (params);
/* Modify drive count, if applicable */
if (command == INT13_GET_PARAMETERS)
{
min_num_drives = ((vdisk_drive & 0x7f) + 1);
if (params->dl < min_num_drives)
params->dl = min_num_drives;
}
}
}
#endif /* defined(__i386__) || defined(__x86_64__) */
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