162 lines
6.0 KiB
ArmAsm
Executable File
162 lines
6.0 KiB
ArmAsm
Executable File
/****************************************************************************
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* arch/x86/src/qemu/qemu_head.S
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*
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* Copyright (C) 2011 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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.file "qemu_head.S"
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/****************************************************************************
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* Pre-processor definitions
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****************************************************************************/
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/* Memory Map: _sbss is the start of the BSS region (see ld.script) _ebss is
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* the end of the BSS regsion (see ld.script). The idle task stack starts at
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* the end of BSS and is of size CONFIG_IDLETHREAD_STACKSIZE. The IDLE thread
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* is the thread that the system boots on and, eventually, becomes the idle,
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* do nothing task that runs only when there is nothing else to run. The
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* heap continues from there until the end of memory. See g_idle_topstack below.
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*/
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#define STACKBASE ((_ebss + 0x1f) & 0xffffffe0)
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#define IDLE_STACK (STACKBASE+CONFIG_IDLETHREAD_STACKSIZE)
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#define HEAP_BASE (STACKBASE+CONFIG_IDLETHREAD_STACKSIZE)
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/****************************************************************************
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* Macros
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****************************************************************************/
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/* Trace macros, use like trace 'i' to print char to serial port. */
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.macro trace, ch
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#ifdef CONFIG_DEBUG
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mov $0x3f8, %dx
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mov $\ch, %al
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out %al, %dx
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#endif
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.endm
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/****************************************************************************
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* Global Symbols
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****************************************************************************/
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.global __start /* Making entry point visible to linker */
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.global os_start /* os_start is defined elsewhere */
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.global up_lowsetup /* up_lowsetup is defined elsewhere */
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.global g_idle_topstack /* The start of the heap */
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/****************************************************************************
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* .text
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****************************************************************************/
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/****************************************************************************
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* Multiboot Header
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****************************************************************************/
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/* Setting up the Multiboot header - see GRUB docs for details */
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.set ALIGN, 1<<0 /* Align loaded modules on page boundaries */
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.set MEMINFO, 1<<1 /* Provide memory map */
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.set FLAGS, ALIGN | MEMINFO /* This is the Multiboot 'flag' field */
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.set MAGIC, 0x1badb002 /* 'magic number' lets bootloader find the header */
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.set CHECKSUM, -(MAGIC + FLAGS) /* Checksum required */
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.text
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.align 4
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.long MAGIC
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.long FLAGS
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.long CHECKSUM
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/****************************************************************************
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* Name: Start
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****************************************************************************/
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.type __start, @function
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__start:
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/* Set up the stack */
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mov $(idle_stack + CONFIG_IDLETHREAD_STACKSIZE), %esp
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/* Multiboot setup */
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push %eax /* Multiboot magic number */
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push %ebx /* Multiboot data structure */
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/* Initialize and start NuttX */
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call up_lowsetup /* Low-level, pre-OS initialization */
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call os_start /* Start NuttX */
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/* NuttX will not return */
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cli
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hang:
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hlt /* Halt machine should NuttX return */
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jmp hang
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.size __start, . - __start
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/****************************************************************************
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* .bss
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****************************************************************************/
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/* The stack for the IDLE task thread is declared in .bss. NuttX boots and
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* initializes on the IDLE thread, then at the completion of OS startup, this
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* thread becomes the thread that executes when there is nothing else to
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* do in the system (see up_idle()).
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*/
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.type idle_stack, @object
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.comm idle_stack, CONFIG_IDLETHREAD_STACKSIZE, 32
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.size idle_stack, CONFIG_IDLETHREAD_STACKSIZE
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/****************************************************************************
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* .rodata
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****************************************************************************/
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.section .rodata, "a"
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/* HEAP BASE: _sbss is the start of the BSS region (see ld.script) _ebss is
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* the end of the BSS region (see ld.script). The heap continues from there
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* until the end of memory.
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*/
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.type g_idle_topstack, @object
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g_idle_topstack:
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.long _ebss
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.size g_idle_topstack, . - g_idle_topstack
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.end
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