5981b3b9a5
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3715 42af7a65-404d-4744-a932-0658087f49c3
141 lines
4.9 KiB
ArmAsm
Executable File
141 lines
4.9 KiB
ArmAsm
Executable File
/************************************************************************************
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* arch/avr/src/avr/up_switchcontext.S
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*
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* Copyright (C) 2011 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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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 "excptmacros.h"
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/************************************************************************************
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* Pre-processor Definitions
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************************************************************************************/
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/************************************************************************************
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* Global Symbols
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************************************************************************************/
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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. The full
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* C function prototype is:
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*
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* void up_switchcontext(uint8_t *saveregs, uint8_t *restoreregs);
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*
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* On Entry:
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* r24-r25: savregs
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* r22-r23: restoreregs
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*
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* Return:
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* up_switchcontext forces a context switch to the task "canned" in restoreregs.
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* It does not 'return' in the normal sense, rather, it will context switch back
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* to the function point. When it does 'return,' it is because the blocked
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* task hat was "pickeled" in the saveregs "can" is again ready to run and has
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* execution priority.
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*
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* Assumptions:
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* global interrupts disabled by the caller.
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*
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************************************************************************************/
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.text
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.globl up_switchcontext
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.func up_switchcontext
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up_switchcontext:
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/* Use X [r26:r27] to reference the save structure. (X is Call-used) */
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movw r26, r24
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/* Save the context to saveregs */
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USER_SAVE
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/* Then fall through to do the full context restore with r24-r5 = restoreregs */
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movw r24, r22
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.endfunc
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/****************************************************************************
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* Name: up_fullcontextrestore
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*
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* Descripion:
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* Restore the full-running context of a thread.
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*
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* Input Parameters:
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* r24-r25 = A pointer to the register save area of the thread to be restored.
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*
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* C Prototype:
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* void up_fullcontextrestore(uint8_t *regs);
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*
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* Assumptions:
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* Interrupts are disabled.
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*
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****************************************************************************/
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.text
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.global up_fullcontextrestore
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.func up_fullcontextrestore
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up_fullcontextrestore:
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/* Use X ]r26:r27] to reference the restore structure. */
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movw r26, r24
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/* Restore the context from the TCB saved registers */
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TCB_RESTORE
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/* And "return" to the new task (using ret not reti so that the interrupt
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* state that we just restored will be preserved).
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*/
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ret
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.endfunc
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.end
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