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/* SPDX-License-Identifier: GPL-2.0-or-later */
/* SPDX-FileCopyrightText: 2009 Juergen Beisert, Pengutronix */
/* SPDX-FileCopyrightText: 1999-2008 Free Software Foundation, Inc. */
/* Mostly stolen from the GRUB2 project */
/**
* @file
* @brief Start the Linux real mode setup code
*
* 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
*/
/*
* void bios_start_linux(unsigned segment)
*
*/
.section .boot.text.bios_start_linux, "ax"
.code32
.globl bios_start_linux
.type bios_start_linux, @function
.extern prot_to_real
bios_start_linux:
/* 'prot_to_real' eats our eax content */
movl %eax, %ebx
addl $0x20, %eax
movw %ax, setup_seg
call prot_to_real
.code16
cli
/* all segment registers are using the same segment */
movw %bx, %ss
movw %bx, %ds
movw %bx, %es
movw %bx, %fs
movw %bx, %gs
/* stack for the setup code (end of heap) */
movw $0x9000, %sp
/* do an 'ljmp' and never return */
.byte 0xea
.word 0
setup_seg:
.word 0
.code32
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