129 lines
4.4 KiB
C
129 lines
4.4 KiB
C
/*
|
|
* FreeRTOS Kernel V10.0.0
|
|
* Copyright (C) 2017 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. If you wish to use our Amazon
|
|
* FreeRTOS name, please do so in a fair use way that does not cause confusion.
|
|
*
|
|
* 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!
|
|
*/
|
|
|
|
/*-----------------------------------------------------------
|
|
* Implementation of functions defined in portable.h for the ARM CM0 port.
|
|
*----------------------------------------------------------*/
|
|
|
|
/* Scheduler includes. */
|
|
#include "FreeRTOS.h"
|
|
#include "task.h"
|
|
|
|
/*
|
|
* Start first task is a separate function so it can be tested in isolation.
|
|
*/
|
|
void vPortStartFirstTask( void );
|
|
|
|
/*
|
|
* Exception handlers.
|
|
*/
|
|
void xPortPendSVHandler( void );
|
|
void vPortSVCHandler( void );
|
|
|
|
|
|
/*-----------------------------------------------------------*/
|
|
|
|
__asm void vPortSVCHandler( void )
|
|
{
|
|
/* This function is no longer used, but retained for backward
|
|
compatibility. */
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|
|
__asm void vPortStartFirstTask( void )
|
|
{
|
|
PRESERVE8
|
|
EXTERN __Vectors
|
|
|
|
/* Use the NVIC offset register to locate the stack. */
|
|
ldr r0, =__Vectors
|
|
ldr r0, [r0]
|
|
/* Set the msp back to the start of the stack. */
|
|
msr msp, r0
|
|
|
|
ldr r3, =pxCurrentTCB /* Obtain location of pxCurrentTCB. */
|
|
ldr r1, [r3]
|
|
ldr r0, [r1] /* The first item in pxCurrentTCB is the task top of stack. */
|
|
adds r0, #32 /* Discard everything up to r0. */
|
|
msr psp, r0 /* This is now the new top of stack to use in the task. */
|
|
movs r0, #2 /* Switch to the psp stack. */
|
|
msr CONTROL, r0
|
|
pop {r0-r5} /* Pop the registers that are saved automatically. */
|
|
mov lr, r5 /* lr is now in r5. */
|
|
cpsie i /* The first task has its context and interrupts can be enabled. */
|
|
pop {pc} /* Finally, pop the PC to jump to the user defined task code. */
|
|
|
|
ALIGN
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|
|
__asm void xPortPendSVHandler( void )
|
|
{
|
|
extern vPortSafeTaskSwitchContext
|
|
extern pxCurrentTCB
|
|
|
|
PRESERVE8
|
|
|
|
mrs r0, psp
|
|
|
|
ldr r3, =pxCurrentTCB /* Get the location of the current TCB. */
|
|
ldr r2, [r3]
|
|
|
|
subs r0, #32 /* Make space for the remaining low registers. */
|
|
str r0, [r2] /* Save the new top of stack. */
|
|
stmia r0!, {r4-r7} /* Store the low registers that are not saved automatically. */
|
|
mov r4, r8 /* Store the high registers. */
|
|
mov r5, r9
|
|
mov r6, r10
|
|
mov r7, r11
|
|
stmia r0!, {r4-r7}
|
|
|
|
push {r3, r14}
|
|
bl vPortSafeTaskSwitchContext
|
|
pop {r2, r3} /* lr goes in r3. r2 now holds tcb pointer. */
|
|
|
|
ldr r1, [r2]
|
|
ldr r0, [r1] /* The first item in pxCurrentTCB is the task top of stack. */
|
|
adds r0, #16 /* Move to the high registers. */
|
|
ldmia r0!, {r4-r7} /* Pop the high registers. */
|
|
mov r8, r4
|
|
mov r9, r5
|
|
mov r10, r6
|
|
mov r11, r7
|
|
|
|
msr psp, r0 /* Remember the new top of stack for the task. */
|
|
|
|
subs r0, #32 /* Go back for the low registers that are not automatically restored. */
|
|
ldmia r0!, {r4-r7} /* Pop low registers. */
|
|
|
|
bx r3
|
|
ALIGN
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|