ref: 0.12.0
src/FreeRTOS/port.c
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/* * 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 CM4F 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 ) __attribute__ (( naked )); /* * Exception handlers. */ void vPortSVCHandler( void ) __attribute__ (( naked )); void xPortPendSVHandler( void ) __attribute__ (( naked )); /*-----------------------------------------------------------*/ void vPortStartFirstTask( void ) { __asm volatile( #if defined(__SES_ARM) " ldr r0, =_vectors \n" /* Locate the stack using _vectors table. */ #else " ldr r0, =__isr_vector \n" /* Locate the stack using __isr_vector table. */ #endif " ldr r0, [r0] \n" " msr msp, r0 \n" /* Set the msp back to the start of the stack. */ " cpsie i \n" /* Globally enable interrupts. */ " cpsie f \n" " dsb \n" " isb \n" #ifdef SOFTDEVICE_PRESENT /* Block kernel interrupts only (PendSV) before calling SVC */ " mov r0, %0 \n" " msr basepri, r0 \n" #endif " svc 0 \n" /* System call to start first task. */ " \n" " .align 2 \n" #ifdef SOFTDEVICE_PRESENT ::"i"(configKERNEL_INTERRUPT_PRIORITY << (8 - configPRIO_BITS)) #endif ); } /*-----------------------------------------------------------*/ void vPortSVCHandler( void ) { __asm volatile ( " ldr r3, =pxCurrentTCB \n" /* Restore the context. */ " ldr r1, [r3] \n" /* Use pxCurrentTCBConst to get the pxCurrentTCB address. */ " ldr r0, [r1] \n" /* The first item in pxCurrentTCB is the task top of stack. */ " ldmia r0!, {r4-r11, r14} \n" /* Pop the registers that are not automatically saved on exception entry and the critical nesting count. */ " msr psp, r0 \n" /* Restore the task stack pointer. */ " isb \n" " mov r0, #0 \n" " msr basepri, r0 \n" " bx r14 \n" " \n" " .align 2 \n" ); } /*-----------------------------------------------------------*/ void xPortPendSVHandler( void ) { /* This is a naked function. */ __asm volatile ( " mrs r0, psp \n" " isb \n" " \n" " ldr r3, =pxCurrentTCB \n" /* Get the location of the current TCB. */ " ldr r2, [r3] \n" " \n" " tst r14, #0x10 \n" /* Is the task using the FPU context? If so, push high vfp registers. */ " it eq \n" " vstmdbeq r0!, {s16-s31} \n" " \n" " stmdb r0!, {r4-r11, r14} \n" /* Save the core registers. */ " \n" " str r0, [r2] \n" /* Save the new top of stack into the first member of the TCB. */ " \n" " stmdb sp!, {r3} \n" " mov r0, %0 \n" " msr basepri, r0 \n" " dsb \n" " isb \n" " bl vTaskSwitchContext \n" " mov r0, #0 \n" " msr basepri, r0 \n" " ldmia sp!, {r3} \n" " \n" " ldr r1, [r3] \n" /* The first item in pxCurrentTCB is the task top of stack. */ " ldr r0, [r1] \n" " \n" " ldmia r0!, {r4-r11, r14} \n" /* Pop the core registers. */ " \n" " tst r14, #0x10 \n" /* Is the task using the FPU context? If so, pop the high vfp registers too. */ " it eq \n" " vldmiaeq r0!, {s16-s31} \n" " \n" " msr psp, r0 \n" " isb \n" " \n" " \n" " bx r14 \n" " \n" " .align 2 \n" ::"i"(configMAX_SYSCALL_INTERRUPT_PRIORITY << (8 - configPRIO_BITS)) ); } |