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/****************************************************************************
* arch/arm/src/arm/up_nommuhead.S
*
* Copyright (C) 2007, 2009-2010, 2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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>
#include "arm.h"
#include "up_internal.h"
#include "up_arch.h"
/****************************************************************************
* Macros
****************************************************************************/
/* This macro will modify r0, r1, r2 and r14 */
#ifdef CONFIG_DEBUG
.macro showprogress, code
mov r0, #\code
bl up_lowputc
.endm
#else
.macro showprogress, code
.endm
#endif
/****************************************************************************
* OS Entry Point
****************************************************************************/
/* We assume the bootloader has already initialized most of the h/w for
* us and that only leaves us having to do some os specific things
* below.
*/
.text
.global __start
.type __start, #function
__start:
/* First, setup initial processor mode */
mov r0, #(SVC_MODE | PSR_I_BIT | PSR_F_BIT )
msr cpsr, r0
showprogress 'A'
/* Setup system stack (and get the BSS range) */
adr r0, .Lbssinit
ldmia r0, {r4, r5, sp}
/* Clear system BSS section */
mov r0, #0
1: cmp r4, r5
strcc r0, [r4], #4
bcc 1b
showprogress 'B'
/* Copy system .data sections to new home in RAM. */
#ifdef CONFIG_BOOT_RUNFROMFLASH
adr r3, .Ldatainit
ldmia r3, {r0, r1, r2}
1: ldmia r0!, {r3 - r10}
stmia r1!, {r3 - r10}
cmp r1, r2
blt 1b
#endif
/* Perform early serial initialization */
mov fp, #0
#ifdef USE_EARLYSERIALINIT
bl up_earlyserialinit
#endif
#ifdef CONFIG_DEBUG
mov r0, #'C'
bl up_putc
mov r0, #'\n'
bl up_putc
#endif
/* Initialize onboard LEDs */
#ifdef CONFIG_ARCH_LEDS
bl board_led_initialize
#endif
#ifdef CONFIG_DEBUG_STACK
/* Write a known value to the IDLE thread stack to support stack
* monitoring logic
*/
adr r3, .Lstkinit
ldmia r3, {r0, r1, r2} /* R0 = start of IDLE stack; R1 = Size of tack; R2 = coloration */
2: /* Top of the loop */
sub r1, r1, #1 /* R1 = Number of words remaining */
cmp r1, #0 /* Check (nwords == 0) */
str r2, [r0], #4 /* Save stack color word, increment stack address */
bne 2b /* Bottom of the loop */
#endif
/* Finally branch to the OS entry point */
mov lr, #0 /* LR = return address (none) */
b os_start /* Branch to os_start */
/* Variables:
* _sbss is the start of the BSS region (see ld.script)
* _ebss is the end of the BSS regsion (see ld.script)
* The idle task stack starts at the end of BSS and is
* of size CONFIG_IDLETHREAD_STACKSIZE. The heap continues
* from there until the end of memory. See g_idle_topstack
* below.
*/
.Lbssinit:
.long _sbss
.long _ebss
.long _ebss+CONFIG_IDLETHREAD_STACKSIZE-4
#ifdef CONFIG_BOOT_RUNFROMFLASH
.Ldatainit:
.long _eronly /* Where .data defaults are stored in FLASH */
.long _sdata /* Where .data needs to reside in SDRAM */
.long _edata
#endif
#ifdef CONFIG_DEBUG_STACK
.type .Lstkinit, %object
.Lstkinit:
.long _ebss /* Beginning of the IDLE stack, then words of IDLE stack */
.long (CONFIG_IDLETHREAD_STACKSIZE >> 2)
.long STACK_COLOR /* Stack coloration word */
.size .Lstkinit, . -.Lstkinit
#endif
.size __start, .-__start
/* This global variable is unsigned long g_idle_topstack and is
* exported from here only because of its coupling to LCO
* above.
*/
.data
.align 4
.globl g_idle_topstack
.type g_idle_topstack, object
g_idle_topstack:
.long _ebss+CONFIG_IDLETHREAD_STACKSIZE
.size g_idle_topstack, .-g_idle_topstack
.end
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