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/**
* @file
*
* @brief ARMV7M Start and Stop Multitasking
*/
/*
* Copyright (c) 2011 Sebastian Huber. All rights reserved.
*
* embedded brains GmbH
* Obere Lagerstr. 30
* 82178 Puchheim
* Germany
* <rtems@embedded-brains.de>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/score/armv7m.h>
#ifdef ARM_MULTILIB_ARCH_V7M
void __attribute__((naked)) _ARMV7M_Start_multitasking(
Context_Control *bsp,
Context_Control *heir
)
{
__asm__ volatile (
/* Store BSP context */
"stm r0, {r4-r11, lr}\n"
"str sp, [r0, %[spctxoff]]\n"
/* Restore heir context */
"ldr r2, [r1, %[spctxoff]]\n"
"msr psp, r2\n"
"ldm r1, {r4-r11, lr}\n"
/* Enable process stack pointer (PSP) */
"mrs r2, control\n"
"orr r2, #0x2\n"
"msr control, r2\n"
/* Return to heir */
"bx lr\n"
:
: [spctxoff] "J" (offsetof(Context_Control, register_sp))
);
}
void __attribute__((naked)) _ARMV7M_Stop_multitasking( Context_Control *bsp )
{
__asm__ volatile (
/* Disable interrupts */
"mov r2, #0x80\n"
"msr basepri_max, r2\n"
/* Restore BSP context */
"ldr r2, [r0, %[spctxoff]]\n"
"msr msp, r2\n"
"ldm r0, {r4-r11, lr}\n"
/* Disable process stack pointer (PSP) */
"mrs r2, control\n"
"bic r2, #0x2\n"
"msr control, r2\n"
/* Return to BSP */
"bx lr\n"
:
: [spctxoff] "J" (offsetof(Context_Control, register_sp))
);
__builtin_unreachable();
}
#endif /* ARM_MULTILIB_ARCH_V7M */
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