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/* SPDX-License-Identifier: GPL-2.0-or-later */
/* SPDX-FileCopyrightText: 2009 Juergen Beisert, Pengutronix */
/* This code was inspired by the GRUB2 project. */
/**
* @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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