99 lines
3.8 KiB
ArmAsm
99 lines
3.8 KiB
ArmAsm
/************************************************************************************
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* arch/arm/src/armv6-m/up_switchcontext.S
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*
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* Copyright (C) 2013 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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#include <arch/irq.h>
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#include "nvic.h"
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#include "svcall.h"
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/************************************************************************************
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* Pre-processor Definitions
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************************************************************************************/
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/************************************************************************************
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* Public Symbols
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************************************************************************************/
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.cpu cortex-m0
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.file "up_switchcontext.S"
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/************************************************************************************
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* Macros
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************************************************************************************/
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/************************************************************************************
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* Public Functions
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************************************************************************************/
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/************************************************************************************
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* Name: up_switchcontext
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*
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* Description:
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* Save the current thread context and restore the specified context.
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* Full prototype is:
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*
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* void up_switchcontext(uint32_t *saveregs, uint32_t *restoreregs);
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*
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* Returned Value:
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* None
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*
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************************************************************************************/
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.align 2
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.code 16
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.thumb_func
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.globl up_switchcontext
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.type up_switchcontext, function
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up_switchcontext:
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/* Perform the System call with R0=1, R1=saveregs, R2=restoreregs */
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mov r2, r1 /* R2: restoreregs */
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mov r1, r0 /* R1: saveregs */
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mov r0, #SYS_switch_context /* R0: context switch */
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svc 0 /* Force synchronous SVCall (or Hard Fault) */
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/* We will get here only after the rerturn from the context switch */
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bx lr
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.size up_switchcontext, .-up_switchcontext
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.end
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