107 lines
4.1 KiB
ArmAsm
107 lines
4.1 KiB
ArmAsm
/************************************************************************************
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* arch/arm/src/armv6-m/up_saveusercontext.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_saveusercontext.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_saveusercontext
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*
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* Description:
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* Save the current thread context. Full prototype is:
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*
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* int up_saveusercontext(uint32_t *saveregs);
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*
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* Return:
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* 0: Normal return
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* 1: Context switch return
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*
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************************************************************************************/
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.text
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.align 2
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.code 16
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.thumb_func
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.globl up_saveusercontext
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.type up_saveusercontext, function
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up_saveusercontext:
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/* Perform the System call with R0=0 and R1=regs */
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mov r1, r0 /* R1: regs */
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mov r0, #SYS_save_context /* R0: save context (also return value) */
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svc 0 /* Force synchronous SVCall (or Hard Fault) */
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/* There are two return conditions. On the first return, R0 (the
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* return value will be zero. On the second return we need to
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* force R0 to be 1.
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*/
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mov r3, #(4*REG_R0) /* R3=Offset to R0 storage */
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add r2, r1, r3 /* R2=Address of R0 storage */
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mov r3, #1 /* R3=Return value of one */
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str r3, [r2, #0] /* Save return value */
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bx lr /* "normal" return with r0=0 or
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* context switch with r0=1 */
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.size up_saveusercontext, .-up_saveusercontext
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.end
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