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/*
* Copyright (C) 2009 Juergen Beisert, Pengutronix
*
* Mostly stolen from the GRUB2 project
* Copyright (C) 1999,2000,2001,2002,2003,2004,2005,2006,2007,2008 Free Software Foundation, Inc.
*
* 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., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*
*/
/**
* @file
* @brief Do BIOS calls to load or save data from disks
*
* @note These functions are running in flat and real mode. Due to some
* other restrictions these routines must running from an address
* space below 0x10000
*/
#ifndef DOXYGEN_SHOULD_SKIP_THIS
/*
* int bios_disk_rw_int13_extensions (int ah, int drive, void *dap)
*
* Call IBM/MS INT13 Extensions (int 13 %ah=AH) for DRIVE. DAP
* is passed for disk address packet. If an error occurs, return
* non-zero, otherwise zero.
*/
.section .boot.text.bios_disk_rw_int13_extensions, "ax"
.code32
.globl bios_disk_rw_int13_extensions
.type bios_disk_rw_int13_extensions, @function
.extern prot_to_real
.extern real_to_prot
bios_disk_rw_int13_extensions:
pushl %ebp
pushl %esi
/* compute the address of disk_address_packet */
movw %cx, %si
xorw %cx, %cx
shrl $4, %ecx /* save the segment to cx */
movb %al, %dh
call prot_to_real /* enter real mode right now */
.code16
movb %dh, %ah
movw %cx, %ds
int $0x13 /* do the operation */
movb %ah, %dl /* save return value */
/* back to protected mode */
DATA32 call real_to_prot
.code32
movb %dl, %al /* return value in %eax */
popl %esi
popl %ebp
ret
#endif
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