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/****************************************************************************
* arch/x86/src/qemu/qemu_head.S
*
* Copyright (C) 2011 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
/****************************************************************************
* .text
****************************************************************************/
#ifdef CONFIG_X86_NASM
global __start /* Making entry point visible to linker */
extern os_start /* os_start is defined elsewhere */
extern up_lowsetup /* up_lowsetup is defined elsewhere */
/* Setting up the Multiboot header - see GRUB docs for details */
MODULEALIGN equ 1<<0 /* Align loaded modules on page boundaries */
MEMINFO equ 1<<1 /* Provide memory map */
FLAGS equ MODULEALIGN | MEMINFO /* This is the Multiboot 'flag' field */
MAGIC equ 0x1BADB002 /* 'magic number' lets bootloader find the header */
CHECKSUM equ -(MAGIC + FLAGS) /* Checksum required */
section .text
align 4
MultiBootHeader:
dd MAGIC
dd FLAGS
dd CHECKSUM
/* Reserve initial kernel stack space */
STACKSIZE equ 0x4000 /* That's 16k */
__start:
mov esp, stack+STACKSIZE /* Set up the stack */
push eax /* Pass Multiboot magic number */
push ebx /* Pass Multiboot info structure */
call up_lowsetup /* Low-level, pre-OS initialization */
call os_start /* Start NuttX */
cli
hang:
hlt /* Halt machine should NuttX return */
jmp hang
section .bss
align 4
stack:
resb STACKSIZE /* Reserve 16k stack on a doubleword boundary */
#else /* !CONFIG_X86_NASM (GAS) */
.global __start /* Making entry point visible to linker */
.global _os_start /* os_start is defined elsewhere */
.global _up_lowsetup /* up_lowsetup is defined elsewhere */
/* Setting up the Multiboot header - see GRUB docs for details */
.set ALIGN, 1<<0 /* Align loaded modules on page boundaries */
.set MEMINFO, 1<<1 /* Provide memory map */
.set FLAGS, ALIGN | MEMINFO /* This is the Multiboot 'flag' field */
.set MAGIC, 0x1BADB002 /* 'magic number' lets bootloader find the header */
.set CHECKSUM, -(MAGIC + FLAGS) /* Checksum required */
.align 4
.long MAGIC
.long FLAGS
.long CHECKSUM
/* Reserve initial kernel stack space */
.set STACKSIZE, 0x4000 /* That is, 16k */
.comm stack, STACKSIZE, 32 /* Reserve 16k stack on a quadword boundary */
__start:
mov $(stack + STACKSIZE), %esp /* Set up the stack */
push %eax /* Multiboot magic number */
push %ebx /* Multiboot data structure */
call _up_lowsetup /* Low-level, pre-OS initialization */
call _os_start /* Start NuttX */
cli
hang:
hlt /* Halt machine should NuttX return */
jmp hang
.end
#endif /* CONFIG_X86_NASM */
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