363 lines
9.4 KiB
C
363 lines
9.4 KiB
C
/**************************************************************************
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* up_savecontext.c
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*
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* Copyright (C) 2007 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 Gregory Nutt 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 <sys/types.h>
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#include <nuttx/irq.h>
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#include "up_internal.h"
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/**************************************************************************
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* Private Definitions
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**************************************************************************/
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/**************************************************************************
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* Private Types
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**************************************************************************/
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/**************************************************************************
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* Private Function Prototypes
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**************************************************************************/
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/**************************************************************************
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* Global Variables
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**************************************************************************/
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/**************************************************************************
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* Private Variables
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**************************************************************************/
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/**************************************************************************
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* Private Functions
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**************************************************************************/
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/**************************************************************************
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* Name: up_savestack
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*
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* Description:
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* Save the entire interrupt stack contents in the provided context
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* structure.
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*
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* Inputs:
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* context - the context structure in which to save the stack info
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*
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* Return:
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* None
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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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static void up_savestack(FAR struct xcptcontext *context, ubyte tos)
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{
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/* Copy the current stack frame from internal RAM to XRAM. */
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ubyte nbytes = tos - (STACK_BASE-1);
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NEAR ubyte *src = (NEAR ubyte*)STACK_BASE;
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FAR ubyte *dest = context->stack;
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context->nbytes = nbytes;
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while (nbytes--)
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{
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*dest++ = *src++;
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}
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}
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/**************************************************************************
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* Name: up_saveregs
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*
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* Description:
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* Save the interrupt registers into the TCB.
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*
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* Inputs:
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* context - the context structure in which to save the register info
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*
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* Return:
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* None
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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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static void up_saveregs(FAR struct xcptcontext *context, ubyte tos)
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{
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/* Copy the irq register save area into the TCB */
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FAR ubyte *src = g_irqregs;
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FAR ubyte *dest = context->regs;
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ubyte nbytes = REGS_SIZE;
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while (nbytes--)
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{
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*dest++ = *src++;
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}
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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_saveregisters
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*
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* Description:
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* Save the current registers in the context save area. This function
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* is called from up_savecontext (below) and also from interrupt
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* handling logic.
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*
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* Note that this function does not save:
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* a, dptr, ie - these are saved in the stack area
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* sp - this can be inferred from g_irqtos or struct xcptontext.nbytes.
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*
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* Inputs:
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* regs - the context register array in which to save the register info
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*
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* Return:
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* None
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*
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**************************************************************************/
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void up_saveregisters(FAR ubyte *regs) _naked
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{
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_asm
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mov a, b
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movx @dptr, a
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inc dptr
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mov a, r2
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movx @dptr, a
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inc dptr
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mov a, r3
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movx @dptr, a
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inc dptr
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mov a, r4
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movx @dptr, a
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inc dptr
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mov a, r5
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movx @dptr, a
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inc dptr
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mov a, r6
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movx @dptr, a
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inc dptr
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mov a, r7
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movx @dptr, a
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inc dptr
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mov a, r0
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movx @dptr, a
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inc dptr
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mov a, r1
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movx @dptr, a
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inc dptr
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mov a, psw
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movx @dptr, a
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clr psw
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inc dptr
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mov a, _bp
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movx @dptr, a
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ret
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_endasm;
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}
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/**************************************************************************
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* Name: up_savecontext
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*
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* Description:
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* Push the current execution context onto the stack, then save the
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* entire stack contents in the provided context structure.
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*
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* Inputs:
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* context - the context structure in which to save the stack info
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*
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* Return:
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* 0 = Normal state save return
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* 1 = This is the matching return from up_restorecontext()
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*
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**************************************************************************/
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ubyte up_savecontext(FAR struct xcptcontext *context) _naked
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{
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_asm
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/* Create the stack frame that we want when it is time to restore
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* this context. The return address will be the return address
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* of this function, the return value will be zero.
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*
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* ...
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* return address (2 bytes, already on the stack)
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* register a=0 (1 byte)
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* register ie (1 byte)
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* register dptr (2 bytes)
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*/
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clr a
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push acc /* ACC = 0 */
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push ie
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mov a, #1
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push acc /* DPL = 1 */
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clr a
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push acc /* DPH = 0 */
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/* Dump the stack contents before they are occupied into XRAM */
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#ifdef CONFIG_SWITCH_FRAME_DUMP
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push dpl
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push dph
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lcall _up_dumpstack
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pop dph
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pop dpl
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#endif
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/* Disable interrupts while we create a snapshot of the stack
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* and registers. At this point, we have 5 bytes on the stack
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* to account for.
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*/
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push ie
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mov ea, 0
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/* Save the registers in the context save area */
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push dpl
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push dph
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mov a, #XCPT_REGS
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add a, dpl
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mov dpl, a
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clr a
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addc a, dph
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mov dph, a
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lcall _up_saveregisters
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pop dph
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pop dpl
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#ifdef CONFIG_SWITCH_FRAME_DUMP
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/* Save the address of the context structure. We will
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* need this later to dump the saved frame. Now we have
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* 7 bytes on the stack to account for.
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*/
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push dpl
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push dph
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/* Push the top of frame stack pointer. We need to
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* decrement the current SP value by three to account
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* for dptr+IE on the stack above the end of the frame.
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*/
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mov a, sp
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subb a, #3
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#else
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/* Push the top of frame stack pointer. We need to
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* decrement the current stack pointer by one to account
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* for IE that we saved on the stack.
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*/
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mov a, sp
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dec a
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#endif
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push acc
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/* Copy the current stack frame from internal RAM to XRAM. */
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lcall _up_savestack
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pop acc
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/* Dump the contents of the saved frame after it has been
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* copied from memory/registers.
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*/
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#ifdef CONFIG_SWITCH_FRAME_DUMP
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pop dph
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pop dpl
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push dpl
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push dph
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lcall _up_dumpframe
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pop dph
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pop dpl
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lcall _up_dumpstack
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#endif
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/* Restore the interrupt state */
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pop ie
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/* Now that we have a snapshot of the desired stack frame saved,
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* we can release the stack frame (all but the return address)
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*/
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mov a, sp
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subb a, #4
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mov sp, a
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mov dpl,#0
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ret
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_endasm;
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}
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/**************************************************************************
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* Name: up_saveirqcontext
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*
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* Description:
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* The interrupt context was saved in g_irqtos and g_irqregs when the
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* interrupt was taken. If a context switch from the interrupted task
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* will be made at the interrupt level, then these saved values must be
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* copied into the TCB.
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*
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* Inputs:
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* context - the structure in which to save the context info
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*
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* Return:
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* None
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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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void up_saveirqcontext(FAR struct xcptcontext *context)
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{
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/* Save the number of bytes in the stack */
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context->nbytes = g_irqtos - (STACK_BASE-1);
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/* Copy the current stack frame from internal RAM to XRAM. */
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up_savestack(context, g_irqtos);
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/* Copy the saved registers into the TCB */
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up_saveregisters(context->regs);
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}
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