portable/GCC/IA32_flat/ISR_Support.h

/*
 * FreeRTOS Kernel V10.3.1
 * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * http://www.FreeRTOS.org
 * http://aws.amazon.com/freertos
 *
 * 1 tab == 4 spaces!
 */

.extern ulTopOfSystemStack
   .extern ulInterruptNesting

/*-----------------------------------------------------------*/

   .macro portFREERTOS_INTERRUPT_ENTRY

/* Save general purpose registers. */
pusha

/* If ulInterruptNesting is zero the rest of the task context will need
 * saving and a stack switch might be required. */
movl ulInterruptNesting, % eax
test % eax, % eax
jne     2f

/* Interrupts are not nested, so save the rest of the task context. */
   .if configSUPPORT_FPU == 1

/* If the task has a buffer allocated to save the FPU context then
 * save the FPU context now. */
movl pucPortTaskFPUContextBuffer, % eax
test % eax, % eax
je      1f
fnsave( % eax ) /* Save FLOP context into ucTempFPUBuffer array. */
fwait

1 :
/* Save the address of the FPU context, if any. */
push pucPortTaskFPUContextBuffer

   .endif /* configSUPPORT_FPU */

/* Find the TCB. */
movl pxCurrentTCB, % eax

/* Stack location is first item in the TCB. */
     movl % esp, ( % eax )

/* Switch stacks. */
movl ulTopOfSystemStack, % esp
movl % esp, % ebp

2 :
/* Increment nesting count. */
add $1, ulInterruptNesting

   .endm
/*-----------------------------------------------------------*/

   .macro portINTERRUPT_EPILOGUE

cli
sub $1, ulInterruptNesting

/* If the nesting has unwound to zero. */
movl ulInterruptNesting, % eax
     test % eax, % eax
     jne     2f

/* If a yield was requested then select a new TCB now. */
movl ulPortYieldPending, % eax
     test % eax, % eax
     je      1f
movl $0, ulPortYieldPending
call vTaskSwitchContext

1 :
/* Stack location is first item in the TCB. */
movl pxCurrentTCB, % eax movl( % eax ), % esp

   .if configSUPPORT_FPU == 1

/* Restore address of task's FPU context buffer. */
pop pucPortTaskFPUContextBuffer

/* If the task has a buffer allocated in which its FPU context is saved,
 * then restore it now. */
movl pucPortTaskFPUContextBuffer, % eax
test % eax, % eax
je      1f
frstor( % eax )
1 :
.endif

2 :
popa

   .endm
/*-----------------------------------------------------------*/

   .macro portFREERTOS_INTERRUPT_EXIT

portINTERRUPT_EPILOGUE
/* EOI. */
movl $0x00, ( 0xFEE000B0 )
iret

   .endm