/*
*********************************************************************************************************
*                                                uC/OS-III
*                                          The Real-Time Kernel
*
*
*                         (c) Copyright 2009-2013; Micrium, Inc.; Weston, FL
*                    All rights reserved.  Protected by international copyright laws.
*
*                                           ARM Cortex-M4 Port
*
* File      : OS_CPU_C.C
* Version   : V3.04.04
* By        : JJL
*             BAN
*             JBL
*
* LICENSING TERMS:
* ---------------
*           uC/OS-III is provided in source form for FREE short-term evaluation, for educational use or 
*           for peaceful research.  If you plan or intend to use uC/OS-III in a commercial application/
*           product then, you need to contact Micrium to properly license uC/OS-III for its use in your 
*           application/product.   We provide ALL the source code for your convenience and to help you 
*           experience uC/OS-III.  The fact that the source is provided does NOT mean that you can use 
*           it commercially without paying a licensing fee.
*
*           Knowledge of the source code may NOT be used to develop a similar product.
*
*           Please help us continue to provide the embedded community with the finest software available.
*           Your honesty is greatly appreciated.
*
*           You can find our product's user manual, API reference, release notes and
*           more information at https://doc.micrium.com.
*           You can contact us at www.micrium.com.
*
* For       : ARMv7M Cortex-M4
* Mode      : Thumb-2 ISA
* Toolchain : IAR EWARM
*********************************************************************************************************
*/

#define   OS_CPU_GLOBALS

#ifdef VSC_INCLUDE_SOURCE_FILE_NAMES
const  CPU_CHAR  *os_cpu_c__c = "$Id: $";
#endif


/*
*********************************************************************************************************
*                                             INCLUDE FILES
*********************************************************************************************************
*/

#include  "../../../../Source/os.h"


#ifdef __cplusplus
extern  "C" {
#endif


/*
*********************************************************************************************************
*                                           IDLE TASK HOOK
*
* Description: This function is called by the idle task.  This hook has been added to allow you to do
*              such things as STOP the CPU to conserve power.
*
* Arguments  : None.
*
* Note(s)    : None.
*********************************************************************************************************
*/

void  OSIdleTaskHook (void)
{
#if OS_CFG_APP_HOOKS_EN > 0u
    if (OS_AppIdleTaskHookPtr != (OS_APP_HOOK_VOID)0) {
        (*OS_AppIdleTaskHookPtr)();
    }
#endif
}


/*
*********************************************************************************************************
*                                       OS INITIALIZATION HOOK
*
* Description: This function is called by OSInit() at the beginning of OSInit().
*
* Arguments  : None.
*
* Note(s)    : None.
*********************************************************************************************************
*/

void  OSInitHook (void)
{
                                                                /* 8-byte align the ISR stack.                            */    
    OS_CPU_ExceptStkBase = (CPU_STK *)(OSCfg_ISRStkBasePtr + OSCfg_ISRStkSize);
    OS_CPU_ExceptStkBase = (CPU_STK *)((CPU_STK)(OS_CPU_ExceptStkBase) & 0xFFFFFFF8);
}


/*
*********************************************************************************************************
*                                         STATISTIC TASK HOOK
*
* Description: This function is called every second by uC/OS-III's statistics task.  This allows your
*              application to add functionality to the statistics task.
*
* Arguments  : None.
*
* Note(s)    : None.
*********************************************************************************************************
*/

void  OSStatTaskHook (void)
{
#if OS_CFG_APP_HOOKS_EN > 0u
    if (OS_AppStatTaskHookPtr != (OS_APP_HOOK_VOID)0) {
        (*OS_AppStatTaskHookPtr)();
    }
#endif
}


/*
*********************************************************************************************************
*                                          TASK CREATION HOOK
*
* Description: This function is called when a task is created.
*
* Arguments  : p_tcb        Pointer to the task control block of the task being created.
*
* Note(s)    : None.
*********************************************************************************************************
*/

void  OSTaskCreateHook (OS_TCB  *p_tcb)
{
#if OS_CFG_APP_HOOKS_EN > 0u
    if (OS_AppTaskCreateHookPtr != (OS_APP_HOOK_TCB)0) {
        (*OS_AppTaskCreateHookPtr)(p_tcb);
    }
#else
    (void)p_tcb;                                                /* Prevent compiler warning                               */
#endif
}


/*
*********************************************************************************************************
*                                           TASK DELETION HOOK
*
* Description: This function is called when a task is deleted.
*
* Arguments  : p_tcb        Pointer to the task control block of the task being deleted.
*
* Note(s)    : None.
*********************************************************************************************************
*/

void  OSTaskDelHook (OS_TCB  *p_tcb)
{
#if OS_CFG_APP_HOOKS_EN > 0u
    if (OS_AppTaskDelHookPtr != (OS_APP_HOOK_TCB)0) {
        (*OS_AppTaskDelHookPtr)(p_tcb);
    }
#else
    (void)p_tcb;                                                /* Prevent compiler warning                               */
#endif
}


/*
*********************************************************************************************************
*                                            TASK RETURN HOOK
*
* Description: This function is called if a task accidentally returns.  In other words, a task should
*              either be an infinite loop or delete itself when done.
*
* Arguments  : p_tcb        Pointer to the task control block of the task that is returning.
*
* Note(s)    : None.
*********************************************************************************************************
*/

void  OSTaskReturnHook (OS_TCB  *p_tcb)
{
#if OS_CFG_APP_HOOKS_EN > 0u
    if (OS_AppTaskReturnHookPtr != (OS_APP_HOOK_TCB)0) {
        (*OS_AppTaskReturnHookPtr)(p_tcb);
    }
#else
    (void)p_tcb;                                                /* Prevent compiler warning                               */
#endif
}


/*
**********************************************************************************************************
*                                       INITIALIZE A TASK'S STACK
*
* Description: This function is called by OS_Task_Create() or OSTaskCreateExt() to initialize the stack
*              frame of the task being created. This function is highly processor specific.
*
* Arguments  : p_task       Pointer to the task entry point address.
*
*              p_arg        Pointer to a user supplied data area that will be passed to the task
*                               when the task first executes.
*
*              p_stk_base   Pointer to the base address of the stack.
*
*              stk_size     Size of the stack, in number of CPU_STK elements.
*
*              opt          Options used to alter the behavior of OS_Task_StkInit().
*                            (see OS.H for OS_TASK_OPT_xxx).
*
* 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 task starts executing.
*
*              (2) All tasks run in Thread mode, using process stack.
*
*              (3) There are two different stack frames depending on whether the Floating-Point(FP)
*                  co-processor is enabled or not.
*
*                  (a) The stack frame shown in the diagram is used when the FP co-processor is not present and
*                      OS_OPT_TASK_SAVE_FP is disabled. In this case, the FP registers and FP Status Control 
*                      register are not saved in the stack frame.
*
*                  (b) If the FP co-processor is present but the OS_OPT_TASK_SAVE_FP is not set, then the stack
*                      frame is saved as shown in diagram (a). Moreover, if OS_OPT_TASK_SAVE_FP is set, then the
*                      FP registers and FP Status Control register are saved in the stack frame.
*
*                      (1) When enabling the FP co-processor, make sure to clear bits ASPEN and LSPEN in the
*                          Floating-Point Context Control Register (FPCCR).
*
*                    +------------+       +------------+
*                    |            |       |            |
*                    +------------+       +------------+
*                    |    xPSR    |       |    xPSR    | 
*                    +------------+       +------------+       
*                    |Return Addr |       |Return Addr |
*                    +------------+       +------------+
*                    |  LR(R14)   |       |   LR(R14)  |
*                    +------------+       +------------+ 
*                    |    R12     |       |     R12    | 
*                    +------------+       +------------+
*                    |    R3      |       |     R3     |
*                    +------------+       +------------+
*                    |    R2      |       |     R0     |
*                    +------------+       +------------+
*                    |    R1      |       |     R1     |
*                    +------------+       +------------+
*                    |    R0      |       |     R0     |
*                    +------------+       +------------+
*                    |    R11     |       |     R11    |
*                    +------------+       +------------+
*                    |    R10     |       |     R10    |
*                    +------------+       +------------+
*                    |    R9      |       |     R9     |
*                    +------------+       +------------+
*                    |    R8      |       |     R8     |
*                    +------------+       +------------+
*                    |    R7      |       |     R7     |
*                    +------------+       +------------+
*                    |    R6      |       |     R6     |
*                    +------------+       +------------+
*                    |    R5      |       |     R5     |
*                    +------------+       +------------+
*                    |    R4      |       |     R4     |
*                    +------------+       +------------+
*                         (a)             |   FPSCR    |
*                                         +------------+
*                                         |     S31    |
*                                         +------------+
*                                                .
*                                                .
*                                                .
*                                         +------------+
*                                         |     S1     |
                                          +------------+
*                                         |     S0     |
*                                         +------------+
*                                              (b)
*
*             (4) The SP must be 8-byte aligned in conforming to the Procedure Call Standard for the ARM architecture 
*
*                    (a) Section 2.1 of the  ABI for the ARM Architecture Advisory Note. SP must be 8-byte aligned 
*                        on entry to AAPCS-Conforming functions states : 
*                    
*                        The Procedure Call Standard for the ARM Architecture [AAPCS] requires primitive 
*                        data types to be naturally aligned according to their sizes (for size = 1, 2, 4, 8 bytes). 
*                        Doing otherwise creates more problems than it solves. 
*
*                        In return for preserving the natural alignment of data, conforming code is permitted 
*                        to rely on that alignment. To support aligning data allocated on the stack, the stack 
*                        pointer (SP) is required to be 8-byte aligned on entry to a conforming function. In 
*                        practice this requirement is met if:
*
*                           (1) At each call site, the current size of the calling function’s stack frame is a multiple of 8 bytes.
*                               This places an obligation on compilers and assembly language programmers.
*
*                           (2) SP is a multiple of 8 when control first enters a program.
*                               This places an obligation on authors of low level OS, RTOS, and runtime library 
*                               code to align SP at all points at which control first enters 
*                               a body of (AAPCS-conforming) code. 
*              
*                       In turn, this requires the value of SP to be aligned to 0 modulo 8:
*
*                           (3) By exception handlers, before calling AAPCS-conforming code.
*
*                           (4) By OS/RTOS/run-time system code, before giving control to an application.
*
*                 (b) Section 2.3.1 corrective steps from the the SP must be 8-byte aligned on entry 
*                     to AAPCS-conforming functions advisory note also states.
* 
*                     " This requirement extends to operating systems and run-time code for all architecture versions 
*                       prior to ARMV7 and to the A, R and M architecture profiles thereafter. Special considerations 
*                       associated with ARMV7M are discussed in §2.3.3"
* 
*                     (1) Even if the SP 8-byte aligment is not a requirement for the ARMv7M profile, the stack is aligned
*                         to 8-byte boundaries to support legacy execution enviroments.
*
*                 (c) Section 5.2.1.2 from the Procedure Call Standard for the ARM 
*                     architecture states :  "The stack must also conform to the following 
*                     constraint at a public interface:
*
*                     (1) SP mod 8 = 0. The stack must be double-word aligned"
*
*                 (d) From the ARM Technical Support Knowledge Base. 8 Byte stack aligment.
*
*                     "8 byte stack alignment is a requirement of the ARM Architecture Procedure 
*                      Call Standard [AAPCS]. This specifies that functions must maintain an 8 byte 
*                      aligned stack address (e.g. 0x00, 0x08, 0x10, 0x18, 0x20) on all external 
*                      interfaces. In practice this requirement is met if:
*
*                      (1) At each external interface, the current stack pointer 
*                          is a multiple of 8 bytes.
* 
*                      (2) Your OS maintains 8 byte stack alignment on its external interfaces 
*                          e.g. on task switches"
*
**********************************************************************************************************
*/

CPU_STK  *OSTaskStkInit (OS_TASK_PTR    p_task,
                         void          *p_arg,
                         CPU_STK       *p_stk_base,
                         CPU_STK       *p_stk_limit,
                         CPU_STK_SIZE   stk_size,
                         OS_OPT         opt)
{
    CPU_STK    *p_stk;

    
    (void)opt;                                                  /* Prevent compiler warning                               */

    p_stk = &p_stk_base[stk_size];                              /* Load stack pointer                                     */
                                                                /* Align the stack to 8-bytes.                            */
    p_stk = (CPU_STK *)((CPU_STK)(p_stk) & 0xFFFFFFF8);
                                                                /* Registers stacked as if auto-saved on exception        */
    *--p_stk = (CPU_STK)0x01000000u;                            /* xPSR                                                   */
    *--p_stk = (CPU_STK)p_task;                                 /* Entry Point                                            */
    *--p_stk = (CPU_STK)OS_TaskReturn;                          /* R14 (LR)                                               */
    *--p_stk = (CPU_STK)0x12121212u;                            /* R12                                                    */
    *--p_stk = (CPU_STK)0x03030303u;                            /* R3                                                     */
    *--p_stk = (CPU_STK)0x02020202u;                            /* R2                                                     */
    *--p_stk = (CPU_STK)p_stk_limit;                            /* R1                                                     */
    *--p_stk = (CPU_STK)p_arg;                                  /* R0 : argument                                          */
                                                                /* Remaining registers saved on process stack             */
    *--p_stk = (CPU_STK)0x11111111u;                            /* R11                                                    */
    *--p_stk = (CPU_STK)0x10101010u;                            /* R10                                                    */
    *--p_stk = (CPU_STK)0x09090909u;                            /* R9                                                     */
    *--p_stk = (CPU_STK)0x08080808u;                            /* R8                                                     */
    *--p_stk = (CPU_STK)0x07070707u;                            /* R7                                                     */
    *--p_stk = (CPU_STK)0x06060606u;                            /* R6                                                     */
    *--p_stk = (CPU_STK)0x05050505u;                            /* R5                                                     */
    *--p_stk = (CPU_STK)0x04040404u;                            /* R4                                                     */
    
#if (OS_CPU_ARM_FP_EN == DEF_ENABLED)
    if ((opt & OS_OPT_TASK_SAVE_FP) != (OS_OPT)0) {
        *--p_stk = (CPU_STK)0x02000000u;                        /* FPSCR                                                  */
                                                                /* Initialize S0-S31 floating point registers             */
        *--p_stk = (CPU_STK)0x41F80000u;                        /* S31                                                    */
        *--p_stk = (CPU_STK)0x41F00000u;                        /* S30                                                    */
        *--p_stk = (CPU_STK)0x41E80000u;                        /* S29                                                    */
        *--p_stk = (CPU_STK)0x41E00000u;                        /* S28                                                    */
        *--p_stk = (CPU_STK)0x41D80000u;                        /* S27                                                    */
        *--p_stk = (CPU_STK)0x41D00000u;                        /* S26                                                    */
        *--p_stk = (CPU_STK)0x41C80000u;                        /* S25                                                    */
        *--p_stk = (CPU_STK)0x41C00000u;                        /* S24                                                    */
        *--p_stk = (CPU_STK)0x41B80000u;                        /* S23                                                    */
        *--p_stk = (CPU_STK)0x41B00000u;                        /* S22                                                    */
        *--p_stk = (CPU_STK)0x41A80000u;                        /* S21                                                    */
        *--p_stk = (CPU_STK)0x41A00000u;                        /* S20                                                    */
        *--p_stk = (CPU_STK)0x41980000u;                        /* S19                                                    */
        *--p_stk = (CPU_STK)0x41900000u;                        /* S18                                                    */
        *--p_stk = (CPU_STK)0x41880000u;                        /* S17                                                    */
        *--p_stk = (CPU_STK)0x41800000u;                        /* S16                                                    */
        *--p_stk = (CPU_STK)0x41700000u;                        /* S15                                                    */
        *--p_stk = (CPU_STK)0x41600000u;                        /* S14                                                    */
        *--p_stk = (CPU_STK)0x41500000u;                        /* S13                                                    */
        *--p_stk = (CPU_STK)0x41400000u;                        /* S12                                                    */
        *--p_stk = (CPU_STK)0x41300000u;                        /* S11                                                    */
        *--p_stk = (CPU_STK)0x41200000u;                        /* S10                                                    */
        *--p_stk = (CPU_STK)0x41100000u;                        /* S9                                                     */
        *--p_stk = (CPU_STK)0x41000000u;                        /* S8                                                     */
        *--p_stk = (CPU_STK)0x40E00000u;                        /* S7                                                     */
        *--p_stk = (CPU_STK)0x40C00000u;                        /* S6                                                     */
        *--p_stk = (CPU_STK)0x40A00000u;                        /* S5                                                     */
        *--p_stk = (CPU_STK)0x40800000u;                        /* S4                                                     */
        *--p_stk = (CPU_STK)0x40400000u;                        /* S3                                                     */
        *--p_stk = (CPU_STK)0x40000000u;                        /* S2                                                     */
        *--p_stk = (CPU_STK)0x3F800000u;                        /* S1                                                     */
        *--p_stk = (CPU_STK)0x00000000u;                        /* S0                                                     */
    }
#endif    

    return (p_stk);
}


/*
*********************************************************************************************************
*                                           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 'OSTCBHighRdyPtr' points to the TCB of the task
*                 that will be 'switched in' (i.e. the highest priority task) and, 'OSTCBCurPtr' points
*                 to the task being switched out (i.e. the preempted task).
*********************************************************************************************************
*/

void  OSTaskSwHook (void)
{
#if OS_CFG_TASK_PROFILE_EN > 0u
    CPU_TS  ts;
#endif
#ifdef  CPU_CFG_INT_DIS_MEAS_EN
    CPU_TS  int_dis_time;
#endif


#if (OS_CPU_ARM_FP_EN == DEF_ENABLED)
    if ((OSTCBCurPtr->Opt & OS_OPT_TASK_SAVE_FP) != (OS_OPT)0) {
        OS_CPU_FP_Reg_Push(OSTCBCurPtr->StkPtr);
    }

    if ((OSTCBHighRdyPtr->Opt & OS_OPT_TASK_SAVE_FP) != (OS_OPT)0) {
        OS_CPU_FP_Reg_Pop(OSTCBHighRdyPtr->StkPtr);
    }
#endif

#if OS_CFG_APP_HOOKS_EN > 0u
    if (OS_AppTaskSwHookPtr != (OS_APP_HOOK_VOID)0) {
        (*OS_AppTaskSwHookPtr)();
    }
#endif

#if (defined(TRACE_CFG_EN) && (TRACE_CFG_EN > 0u))
    TRACE_OS_TASK_SWITCHED_IN(OSTCBHighRdyPtr);                 /* Record the event.                                      */
#endif

#if OS_CFG_TASK_PROFILE_EN > 0u
    ts = OS_TS_GET();
    if (OSTCBCurPtr != OSTCBHighRdyPtr) {
        OSTCBCurPtr->CyclesDelta  = ts - OSTCBCurPtr->CyclesStart;
        OSTCBCurPtr->CyclesTotal += (OS_CYCLES)OSTCBCurPtr->CyclesDelta;
    }

    OSTCBHighRdyPtr->CyclesStart = ts;
#endif

#ifdef  CPU_CFG_INT_DIS_MEAS_EN
    int_dis_time = CPU_IntDisMeasMaxCurReset();                 /* Keep track of per-task interrupt disable time          */
    if (OSTCBCurPtr->IntDisTimeMax < int_dis_time) {
        OSTCBCurPtr->IntDisTimeMax = int_dis_time;
    }
#endif

#if OS_CFG_SCHED_LOCK_TIME_MEAS_EN > 0u
                                                                /* Keep track of per-task scheduler lock time             */
    if (OSTCBCurPtr->SchedLockTimeMax < OSSchedLockTimeMaxCur) {
        OSTCBCurPtr->SchedLockTimeMax = OSSchedLockTimeMaxCur;
    }
    OSSchedLockTimeMaxCur = (CPU_TS)0;                          /* Reset the per-task value                               */
#endif
}


/*
*********************************************************************************************************
*                                              TICK HOOK
*
* Description: This function is called every tick.
*
* Arguments  : None.
*
* Note(s)    : 1) This function is assumed to be called from the Tick ISR.
*********************************************************************************************************
*/

void  OSTimeTickHook (void)
{
#if OS_CFG_APP_HOOKS_EN > 0u
    if (OS_AppTimeTickHookPtr != (OS_APP_HOOK_VOID)0) {
        (*OS_AppTimeTickHookPtr)();
    }
#endif
}


/*
*********************************************************************************************************
*                                          SYS TICK HANDLER
*
* Description: Handle the system tick (SysTick) interrupt, which is used to generate the uC/OS-II tick
*              interrupt.
*
* Arguments  : None.
*
* Note(s)    : 1) This function MUST be placed on entry 15 of the Cortex-M3 vector table.
*********************************************************************************************************
*/

void  OS_CPU_SysTickHandler (void)
{
    CPU_SR_ALLOC();


    CPU_CRITICAL_ENTER();
    OSIntNestingCtr++;                                      /* Tell uC/OS-III that we are starting an ISR             */
    CPU_CRITICAL_EXIT();

    OSTimeTick();                                           /* Call uC/OS-III's OSTimeTick()                          */

    OSIntExit();                                            /* Tell uC/OS-III that we are leaving the ISR             */
}


/*
*********************************************************************************************************
*                                         INITIALIZE SYS TICK
*
* Description: Initialize the SysTick.
*
* Arguments  : cnts         Number of SysTick counts between two OS tick interrupts.
*
* Note(s)    : 1) This function MUST be called after OSStart() & after processor initialization.
*********************************************************************************************************
*/

void  OS_CPU_SysTickInit (CPU_INT32U  cnts)
{
    CPU_INT32U  prio;


    CPU_REG_NVIC_ST_RELOAD = cnts - 1u;

                                                            /* Set SysTick handler prio.                              */
    prio  = CPU_REG_NVIC_SHPRI3;
    prio &= DEF_BIT_FIELD(24, 0);
    prio |= DEF_BIT_MASK(OS_CPU_CFG_SYSTICK_PRIO, 24);

    CPU_REG_NVIC_SHPRI3 = prio;

                                                            /* Enable timer.                                          */
    CPU_REG_NVIC_ST_CTRL |= CPU_REG_NVIC_ST_CTRL_CLKSOURCE |
                            CPU_REG_NVIC_ST_CTRL_ENABLE;
                                                            /* Enable timer interrupt.                                */
    CPU_REG_NVIC_ST_CTRL |= CPU_REG_NVIC_ST_CTRL_TICKINT;
}

#ifdef __cplusplus
}
#endif
