📄 os_cpu_c.c
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/*
*********************************************************************************************************
* uC/OS-II
* The Real-Time Kernel
*
* (c) Copyright 1992-1998, Jean J. Labrosse, Plantation, FL
* All Rights Reserved
* (c) Copyright ARM Limited 1999. All rights reserved.
*
* ARM Specific code
*
*
* File : OS_CPU_C.C
*********************************************************************************************************
*/
#define OS_CPU_GLOBALS
#include "ucos_ii.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.
*
* 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) : Interrupts are enabled when your task starts executing. You can change this by setting the
* PSW to 0x0002 instead. In this case, interrupts would be disabled upon task startup. The
* application code would be responsible for enabling interrupts at the beginning of the task
* code. You will need to modify OSTaskIdle() and OSTaskStat() so that they enable
* interrupts. Failure to do this will make your system crash!
*********************************************************************************************************
*/
#if 0
void OSStartHighRdy (void)
{
OS_STK* pstk; //R4
int temp=0; //R5
OSTaskSwHook();
pstk=OSTCBHighRdy->OSTCBStkPtr;
asm("MOV R5,SP");
asm("LDMIA SP!{R4}");
asm("MOV SP,R4");
OSRunning = TRUE;
//Restore all processor registers from the task's stack;
//Execute a return from interrupt instruction;
}
void OSCtxSw(void)
{
保存处理器寄存器;
将当前任务的堆栈指针保存到当前任务的OS_TCB中:
OSTCBCur->OSTCBStkPtr = Stack pointer;
调用用户定义的OSTaskSwHook();
OSTCBCur = OSTCBHighRdy;
OSPrioCur = OSPrioHighRdy;
得到需要恢复的任务的堆栈指针:
Stack pointer = OSTCBHighRdy->OSTCBStkPtr;
将所有处理器寄存器从新任务的堆栈中恢复出来;
执行中断返回指令;
}
void OSIntCtxSw(void)
{
OSIntExit();
OSIntCtxSw()过程中压入堆栈的多余内容;
将当前任务堆栈指针保存到当前任务的OS_TCB中:
OSTCBCur->OSTCBStkPtr = 堆栈指针;
调用用户定义的OSTaskSwHook();
OSTCBCur = OSTCBHighRdy;
OSPrioCur = OSPrioHighRdy;
得到需要恢复的任务的堆栈指针:
堆栈指针 = OSTCBHighRdy->OSTCBStkPtr;
将所有处理器寄存器从新任务的堆栈中恢复出来;
执行中断返回指令;
}
void OSTickISR(void)
{
保存处理器寄存器;
调用OSIntEnter()或者直接将 OSIntNesting加1;
调用OSTimeTick();
调用OSIntExit();
恢复处理器寄存器;
执行中断返回指令;
}
#endif
OS_STK *OSTaskStkInit(void (*task)(void *p_arg), void *p_arg, OS_STK *ptos, INT16U opt)
//void *OSTaskStkInit (void (*task)(void *pd), void *pdata, void *ptos, INT16U opt)
{
//unsigned int *stk;
OS_STK* stk;
opt = opt; /* 'opt' is not used, prevent warning */
stk = (unsigned int *)ptos; /* Load stack pointer */
/* build a context for the new task */
//*--stk = (unsigned int) task; /* pc */
*stk = (unsigned int) task; /* pc */ //the ptos is the empty stack
*--stk = (unsigned int) task; /* lr */
*--stk = 0; /* r12 */
*--stk = 0; /* r11 */
*--stk = 0; /* r10 */
*--stk = 0; /* r9 */
*--stk = 0; /* r8 */
*--stk = 0; /* r7 */
*--stk = 0; /* r6 */
*--stk = 0; /* r5 */
*--stk = 0; /* r4 */
*--stk = 0; /* r3 */
*--stk = 0; /* r2 */
*--stk = 0; /* r1 */
*--stk = (unsigned int) p_arg; /* r0 */
//*--stk = (SYS32MODE|0x0); /* cpsr IRQ, FIQ disable*/
*--stk = (SYS32MODE|0x0); /* spsr IRQ, FIQ disable */
return ((OS_STK*)stk);
}
/*$PAGE*/
#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)
{
ptcb = ptcb; /* Prevent compiler warning */
}
/*
*********************************************************************************************************
* 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)
{
ptcb = ptcb; /* Prevent compiler warning */
}
/*
*********************************************************************************************************
* 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)
{
}
/*
*********************************************************************************************************
* 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)
{
}
#if OS_VERSION >= 204
void OSInitHookBegin(void)
{
}
void OSInitHookEnd(void)
{
}
#endif
#if OS_VERSION >= 204
void OSTCBInitHook(OS_TCB *ptcb)
{
}
#endif
#if OS_VERSION >= 251
void OSTaskIdleHook(void)
{
}
#endif
#endif //HOOK EN
#if 0
#define BUILD_DATE "Date: " __DATE__ "\n"
/*
* Initialize an ARM Target board
*/
void
ARMTargetInit(void)
{
/* ---- Tell the world who we are ---------------------------------- */
uHALr_printf("uCOS-II Running on a") ;
#if defined(EBSA285)
uHALr_printf("n EBSA-285 (21285 evaluation board)\n") ;
#elif defined(BRUTUS)
uHALr_printf(" Brutus (SA-1100 verification platform)\n") ;
#elif defined(INTEGRATOR)
uHALr_printf("n Integrator board\n") ;
#elif defined(PROSPECTOR)
uHALr_printf(" Prospector board\n") ;
#elif defined(SAMSUNG)
uHALr_printf(" SAMSUNG board\n");
#else
uHALr_printf("n unknown ARM board\n") ;
#endif
uHALr_printf(uHAL_VERSION_STRING);
uHALr_printf("\n") ;
uHALr_printf(BUILD_DATE);
uHALr_printf("\n") ;
#ifdef DEBUG
uHALr_printf("Initialising target\n");
#endif
/* ---- disable the MMU ------------------------------------- */
uHALr_ResetMMU();
/* ---- disable interrupts (IRQs) --------------------------------- */
ARMDisableInt();
/* ---- soft vectors ---------------------------------------------- */
#ifdef DEBUG
uHALr_printf("Setting up soft vectors\n");
#endif
/* Define pre & post-process routines for Interrupt */
uHALir_DefineIRQ((void *)IrqStart, (void *)IrqFinish, (void *) 0);
uHALr_InitInterrupts();
#ifdef DEBUG
uHALr_printf("Timer init\n");
#endif
uHALr_InitTimers();
#ifdef DEBUG
uHALr_printf("targetInit() complete\n");
#endif
} /* targetInit */
/* start the ARM target running */
void
ARMTargetStart(void)
{
#ifdef DEBUG
uHALr_printf("Starting target\n") ;
#endif
/* request the system timer */
if (uHALr_RequestSystemTimer(
(void *) OSTimeTick,
(const unsigned char *)"uCOS-II") <= 0)
uHALr_printf("Timer/IRQ busy\n");
/* Start system timer & enable the interrupt. */
uHALr_InstallSystemTimer();
}
extern void IRQContextSwap(void); /* post DispatchIRQ processing (the _real_ one) */
/* just 'notice' that we need to change context */
int need_to_swap_context = 0 ;
void OSIntCtxSw(void) {
need_to_swap_context = 1;
}
/* This is what uCOS does at the start of an IRQ */
void IrqStart(void)
{
/* increment nesting counter */
OSIntNesting++;
}
/* This is what uCOS does at the end of an IRQ */
void *IrqFinish(void)
{
OSIntExit() ;
if (need_to_swap_context) {
// need_to_swap_context = 0 ;
return ((void *)IRQContextSwap) ;
} else {
return (void *)0;
}
}
#endif
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