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/*
* Copyright (C) 2009 Juergen Beisert, Pengutronix
*
* This code was inspired by the GRUB2 project.
*
* 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.
*
*
*/
/**
* @file
* @brief Query the memory layout information from the BIOS
*
* Note: This function is running in flat and real mode. Due to some
* other restrictions it must running from an address space below 0x10000
*/
/**
* @fn unsigned short bios_get_memsize(void)
* @brief Does a BIOS call "INT 15H, AH=88H" to get extended memory size
* @return Extended memory size in KB
*
* @note This call is limited to 64 MiB. So, if the system provides more than
* 64 MiB of memory, still 64 MiB are reported.
*
*/
.section .boot.text.bios_get_memsize, "ax"
.code32
.globl bios_get_memsize
.type bios_get_memsize, @function
.extern prot_to_real
bios_get_memsize:
pushl %ebp
call prot_to_real /* enter real mode */
.code16
movb $0x88, %ah
int $0x15
movw %ax, %dx
DATA32 call real_to_prot
.code32
movw %dx, %ax
popl %ebp
ret
.size bios_get_memsize, .-bios_get_memsize
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