📄 os_cpu_c.c
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/*
*********************************************************************************************************
* uC/OS-II
* The Real-Time Kernel
*
* (c) Copyright 2002, Nathan Brown, Longview, TX
* http://www.sputnickonline.com/
* All Rights Reserved
*
* PIC18xxxx Specific Code
* V1.00 - October 27, 2002
*
* File : OS_CPU_C.C
* By : Nathan Brown
*********************************************************************************************************
*/
#define OS_CPU_GLOBALS
#include "includes.h"
/*
*********************************************************************************************************
* INITIALIZE A TASK'S STACK
*
* Description: This function is called by either OSTaskCreate() or OSTaskCreateExt() to initialize the
* stack frame of the task being created. This function is highly processor specific.
*
* Arguments : task is a pointer to the task code
*
* pdata is a pointer to a user supplied data area that will be passed to the task
* when the task first executes. For the TASKING compiler, 'pdata' is passed
* in R1:R0.
*
* ptos is a pointer to the top of stack. It is assumed that 'ptos' points to
* a 'free' entry on the task stack. If OS_STK_GROWTH is set to 1 then
* 'ptos' will contain the HIGHEST valid address of the stack. Similarly, if
* OS_STK_GROWTH is set to 0, the 'ptos' will contains the LOWEST valid address
* of the stack.
*
* opt specifies options that can be used to alter the behavior of OSTaskStkInit().
* (see uCOS_II.H for OS_TASK_OPT_???).
*
* Returns : Always returns the location of the new top-of-stack' once the processor registers have
* been placed on the stack in the proper order.
*
* Note(s) : 1) Interrupts are enabled when your task starts executing.
*
* 2) Save the current context onto the stack
*
* 3) The return addresses are in a different stack, so save all of those into the stack
*
* 4) The last stacking operation (before the return) places the number of return stack
* items in the software stack.
*********************************************************************************************************
*/
OS_STK *OSTaskStkInit (void (*task)(void *pd), void *pdata, OS_STK *ptos, INT16U opt)
{
OS_STK *stk;
stk = ptos; // local pointer to our new proccess stack
*stk++ = (OS_STK)*(((INT8U*)&pdata)); // data being passed
*stk++ = (OS_STK)*(((INT8U*)&pdata)+1);
*stk++ = 0xFF; // <-- FSR1 Pointer position on function call.
*stk++ = 0x1A; // STATUS register
*stk++ = 0x1B; // BSR register
*stk++ = 0x1C; // W register
*stk++ = 0x1D; // FSR0L register
*stk++ = 0x1E; // FSR0H register
*stk++ = 0x1F; // FSR2L register
*stk++ = 0x2A; // FSR2H register
*stk++ = 0x2B; // TBLPTRL Prog Mem Table Pointer Upper
*stk++ = 0x2C; // TBLPTRH Prog Mem Table Pointer High
*stk++ = 0x2D; // TBLPTRU Prog Mem Table Pointer Low
*stk++ = 0x2E; // PRODL Product Reg high
*stk++ = 0x2F; // PRODH Product Reg low
*stk++ = 0x3A; // AARGB3
*stk++ = 0x3B; // AARGB2
*stk++ = 0x3C; // AARGB1
*stk++ = 0x3D; // AARGB0
// first return address, the task address, goes on the hardware return stack in a context switch
*stk++ = (OS_STK)*(((INT8U*)&task)); // TOSL - Top of stack - Lower bits
*stk++ = (OS_STK)*(((INT8U*)&task)+1); // TOSH - Top of stack - High bits
*stk++ = (OS_STK)*(((INT8U*)&task)+2); // TOSU - Top of stack - Uppre bits
// repeat...
*stk++ = 0x01; // size of return stack
return ((OS_STK *)stk); // Return pointer to task's top-of-stack
}
#if OS_CPU_HOOKS_EN
/*
*********************************************************************************************************
* TASK CREATION HOOK
*
* Description: This function is called when a task is created.
*
* Arguments : ptcb is a pointer to the task control block of the task being created.
*
* Note(s) : 1) Interrupts are disabled during this call.
*********************************************************************************************************
*/
void OSTaskCreateHook(OS_TCB *ptcb)
{
}
/*
*********************************************************************************************************
* TASK DELETION HOOK
*
* Description: This function is called when a task is deleted.
*
* Arguments : ptcb is a pointer to the task control block of the task being deleted.
*
* Note(s) : 1) Interrupts are disabled during this call.
*********************************************************************************************************
*/
void OSTaskDelHook (OS_TCB *ptcb)
{
}
/*
*********************************************************************************************************
* TASK SWITCH HOOK
*
* Description: This function is called when a task switch is performed. This allows you to perform other
* operations during a context switch.
*
* Arguments : none
*
* Note(s) : 1) Interrupts are disabled during this call.
* 2) It is assumed that the global pointer 'OSTCBHighRdy' points to the TCB of the task that
* will be 'switched in' (i.e. the highest priority task) and, 'OSTCBCur' points to the
* task being switched out (i.e. the preempted task).
*********************************************************************************************************
*/
void OSTaskSwHook (void)
{
// Clear watch dog timer on context switches. If enabled, the processor
// will reset if this does not get called (application frozen).
_asm
CLRWDT
_endasm
}
/*
*********************************************************************************************************
* STATISTIC TASK HOOK
*
* Description: This function is called every second by uC/OS-II's statistics task. This allows your
* application to add functionality to the statistics task.
*
* Arguments : none
*********************************************************************************************************
*/
void OSTaskStatHook (void)
{
}
/*
*********************************************************************************************************
* TICK HOOK
*
* Description: This function is called every tick.
*
* Arguments : none
*
* Note(s) : 1) Interrupts may or may not be ENABLED during this call.
*********************************************************************************************************
*/
void OSTimeTickHook (void)
{
}
/*
*********************************************************************************************************
* OSTCBInit() HOOK
*
* Description: This function is called by OSTCBInit() after setting up most of the TCB.
*
* Arguments : ptcb is a pointer to the TCB of the task being created.
*
* Note(s) : 1) Interrupts may or may not be ENABLED during this call.
*********************************************************************************************************
*/
#if OS_VERSION > 203
void OSTCBInitHook(struct os_tcb *ptcb)
{
}
#endif
/*
*********************************************************************************************************
* IDLE TASK HOOK
*
* Description: This function is called by OS_TaskIdle() which is executed whenever no other task is
* ready to run. This function can put the CPU to sleep, ready to be woken by an interupt
* or it can blink a LED to indicate how busy the processor is.
*
* Arguments : none
*********************************************************************************************************
*/
void OSTaskIdleHook (void)
{
}
/*
*********************************************************************************************************
* OS INITIALIZATION HOOK
* (BEGINNING)
*
* Description: This function is called by OSInit() at the beginning of OSInit().
*
* Arguments : none
*
* Note(s) : 1) Interrupts should be disabled during this call.
*********************************************************************************************************
*/
#if OS_VERSION > 203
void OSInitHookBegin (void)
{
}
#endif
/*
*********************************************************************************************************
* OS INITIALIZATION HOOK
* (END)
*
* Description: This function is called by OSInit() at the end of OSInit().
*
* Arguments : none
*
* Note(s) : 1) Interrupts should be disabled during this call.
*********************************************************************************************************
*/
#if OS_VERSION > 203
void OSInitHookEnd (void)
{
}
#endif
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* START HIGHEST PRIORITY TASK
*
* Description : This function is called by OSStart() to start the highest priority task that was created
* by your application before calling OSStart().
*
* Arguments : none
*
* Note(s) : 1) Interupts are disabled when calling.
*
* 2) The stack frame (8-bit wide stack) is assumed to look as follows:
*
* LOW MEMORY
* - 23 pdata (lower 8 bits)
* - 22 pdata (upper 8 bits)
* - 21 XX (pointed to by FSR1, frame pointer)
* - 20 STATUS register
* - 19 BSR register
* - 18 W register
* - 17 FSR0L register
* - 16 FSR0H register
* - 15 FSR2L register (frame pointer, low)
* - 14 FSR2H register (frame pointer, high)
* - 13 TBLPTRL register
* - 12 TBLPTRH register
* - 11 TBLPTRU register
* - 10 PRODL register
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