os_cpu_c.c

《嵌入式实时操作系统μC／OS-Ⅱ》的源码

/*
*********************************************************************************************************
*                                               uC/OS-II
*                                         The Real-Time Kernel
*
*                        (c) Copyright 1992-2002, Jean J. Labrosse, Weston, FL
*                                          All Rights Reserved
*
*                                          80x86 Specific code
*                                 LARGE MEMORY MODEL WITH FLOATING-POINT
*                                          Borland C/C++ V4.51
*
*
* File         : OS_CPU_C.C
* By           : Jean J. Labrosse
*********************************************************************************************************
*/

#define  OS_CPU_GLOBALS
#include "includes.h"

/*$PAGE*/
/*
*********************************************************************************************************
*                                             LOCAL CONSTANTS
*
* Note(s) : 1) OS_NTASKS_FP  establishes the number of tasks capable of supporting floating-point.  One
*              task is removed for the idle task because it doesn't do floating-point at all.
*           2) OS_FP_STORAGE_SIZE  currently allocates 128 bytes of storage even though the 80x86 FPU 
*              only require 108 bytes to save the FPU context.  I decided to allocate 128 bytes for 
*              future expansion.  
*********************************************************************************************************
*/

#define  OS_NTASKS_FP         (OS_MAX_TASKS + OS_N_SYS_TASKS - 1)
#define  OS_FP_STORAGE_SIZE   128

/*
*********************************************************************************************************
*                                             LOCAL VARIABLES
*********************************************************************************************************
*/

static  OS_MEM  *OSFPPartPtr;          /* Pointer to memory partition holding FPU storage areas        */

                                       /* I used INT32U to ensure that storage is aligned on a ...     */
                                       /* ... 32-bit boundary.                                         */
static  INT32U   OSFPPart[OS_NTASKS_FP][OS_FP_STORAGE_SIZE / sizeof(INT32U)];

/*$PAGE*/
/*
*********************************************************************************************************
*                                        INITIALIZE FP SUPPORT
*
* Description: This function is called to initialize the memory partition needed to support context
*              switching the Floating-Point registers.  This function MUST be called AFTER calling
*              OSInit().
*
* Arguments  : none
*
* Returns    : none
*
* Note(s)    : 1) Tasks that are to use FP support MUST be created with OSTaskCreateExt().
*              2) For the 80x86 FPU, 108 bytes are required to save the FPU context.  I decided to
*                 allocate 128 bytes for future expansion.  Also, I used INT32U to ensure that storage 
*                 is aligned on a 32-bit boundary.
*              3) I decided to 'change' the 'Options' attribute for the statistic task in case you
*                 use OSTaskStatHook() and need to perform floating-point operations in this function.
*                 This only applies if OS_TaskStat() was created with OSTaskCreateExt().
*********************************************************************************************************
*/

void  OSFPInit (void)
{
    INT8U    err;
#if OS_TASK_STAT_EN && OS_TASK_CREATE_EXT_EN
    OS_TCB  *ptcb;
    void    *pblk;
#endif
    
    
    OSFPPartPtr = OSMemCreate(&OSFPPart[0][0], OS_NTASKS_FP, OS_FP_STORAGE_SIZE, &err);
    
#if OS_TASK_STAT_EN && OS_TASK_CREATE_EXT_EN       /* CHANGE 'OPTIONS' for OS_TaskStat()               */
    ptcb            = OSTCBPrioTbl[OS_STAT_PRIO];
    ptcb->OSTCBOpt |= OS_TASK_OPT_SAVE_FP;         /* Allow floating-point support for Statistic task  */
    pblk            = OSMemGet(OSFPPartPtr, &err); /* Get storage for FPU registers                    */
    if (pblk != (void *)0) {                       /* Did we get a memory block?                       */
        ptcb->OSTCBExtPtr = pblk;                  /* Yes, Link to task's TCB                          */
        OSFPSave(pblk);                            /*      Save the FPU registers in block             */
    }
#endif
}

/*$PAGE*/
/*
*********************************************************************************************************
*                                       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_CPU_HOOKS_EN > 0 && 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_CPU_HOOKS_EN > 0 && OS_VERSION > 203
void  OSInitHookEnd (void)
{
    OSFPInit();
}
#endif

/*$PAGE*/
/*
*********************************************************************************************************
*                                          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.
*              2) I decided to change the options on the statistic task to allow for floating-point in
*                 case you decide to do math. in OSTaskStatHook().
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0
void OSTaskCreateHook (OS_TCB *ptcb)
{
    INT8U  err;
    void  *pblk;
    
    
    if (ptcb->OSTCBOpt & OS_TASK_OPT_SAVE_FP) {  /* See if task needs FP support                      */
        pblk = OSMemGet(OSFPPartPtr, &err);      /* Yes, Get storage for FPU registers                */
        if (pblk != (void *)0) {                 /*      Did we get a memory block?                   */
            ptcb->OSTCBExtPtr = pblk;            /*      Yes, Link to task's TCB                      */
            OSFPSave(pblk);                      /*           Save the FPU registers in block         */
        }
    }
}
#endif

/*
*********************************************************************************************************
*                                           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.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0
void OSTaskDelHook (OS_TCB *ptcb)
{
    if (ptcb->OSTCBOpt & OS_TASK_OPT_SAVE_FP) {            /* See if task had FP support               */