ucos.c

这是UCOS的源代码,上面包含了UCOS1和UCOS2两份,从中可以看到它们之间的不同!

/*
************************************************************
*                         UCOS.C
*                         KERNEL
************************************************************
*/
#include "INCLUDES.H"
#ifdef   TURBOC
#pragma  inline
#endif
/*
************************************************************
*                         TABLES
************************************************************
*/
UBYTE const OSMapTbl[]   = {0x01, 0x02, 0x04, 0x08,
                            0x10, 0x20, 0x40, 0x80};
UBYTE const OSUnMapTbl[] = {
    0, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0};
/*
************************************************************
*                GLOBAL AND LOCAL VARIABLES
************************************************************
*/
        OS_TCB     *OSTCBCur;
        OS_TCB     *OSTCBHighRdy;
        OS_TCB     *OSTCBList;
        OS_TCB     *OSTCBPrioTbl[64];
        BOOLEAN     OSRunning;
        UBYTE       OSRdyGrp;
        UBYTE       OSRdyTbl[8];
        UBYTE       OSLockNesting;
        UBYTE       OSIntNesting;
        OS_TCB     *OSTCBFreeList;
/*
************************************************************
*                LOCAL FUNCTION PROTOTYPES
************************************************************
*/
static void  far   OSTaskIdle(void *data);
/*
************************************************************
*                   uCOS INITIALIZATION
************************************************************
*/
void OSInit(void *idle_task_stk, UBYTE maxtasks)
{
    UBYTE i;


    OSTCBCur      = (OS_TCB *)0;
    OSTCBList     = (OS_TCB *)0;
    OSIntNesting  = 0;
    OSLockNesting = 0;
    OSRunning     = 0;
    OSRdyGrp      = 0;
    for (i = 0; i < 8; i++) {
        OSRdyTbl[i] = 0;
    }
    for (i = 0; i < 64; i++) {
        OSTCBPrioTbl[i] = (OS_TCB *)0;
    }
    for (i = 0; i < (maxtasks - 1); i++) {
        OSTCBTbl[i].OSTCBNext = &OSTCBTbl[i+1];
    }
    OSTCBTbl[maxtasks-1].OSTCBNext = (OS_TCB *)0;
    OSTCBFreeList                  = &OSTCBTbl[0];
    OSTaskCreate(OSTaskIdle, (void *)0, idle_task_stk, OS_LO_PRIO);
}
/*
************************************************************
*                       IDLE TASK
************************************************************
*/
static void far OSTaskIdle(void *data)
{
    data = data;
    while (1)
        ;
}
/*
************************************************************
*                    START MULTITASKING
************************************************************
*/
void OSStart(void)
{
    UBYTE x, y, p;


    y            = OSUnMapTbl[OSRdyGrp];
    x            = OSRdyTbl[y];
    p            = (y << 3) + OSUnMapTbl[x];
    OSTCBHighRdy = OSTCBPrioTbl[p];
    OSTCBCur     = OSTCBHighRdy;
    OSRunning    = 1;
    OSStartHighRdy();
}
/*
************************************************************
*                RUN HIGHEST PRIORITY TASK
************************************************************
*/
void OSSched(void)
{
    UBYTE x, y, p;


    OS_ENTER_CRITICAL();
    if (OSLockNesting == 0 && OSIntNesting == 0) {
        y            = OSUnMapTbl[OSRdyGrp];
        x            = OSRdyTbl[y];
        p            = (y << 3) + OSUnMapTbl[x];
        OSTCBHighRdy = OSTCBPrioTbl[p];
        if (OSTCBHighRdy != OSTCBCur) {
            OS_TASK_SW();
        }
    }
    OS_EXIT_CRITICAL();
}
/*
************************************************************
*                        ENTER ISR
************************************************************
*/
void OSIntEnter(void)
{
    OS_ENTER_CRITICAL();
    OSIntNesting++;
    OS_EXIT_CRITICAL();
}
/*
************************************************************
*                        EXIT ISR
************************************************************
*/
void OSIntExit(void)
{
    UBYTE x, y, p;


    OS_ENTER_CRITICAL();
    if (--OSIntNesting == 0 && OSLockNesting == 0) {
        y            = OSUnMapTbl[OSRdyGrp];
        x            = OSRdyTbl[y];
        p            = (y << 3) + OSUnMapTbl[x];
        OSTCBHighRdy = OSTCBPrioTbl[p];
        if (OSTCBHighRdy != OSTCBCur) {
            OSIntCtxSw();
        }
    }
    OS_EXIT_CRITICAL();
}
/*
************************************************************
*          DELAY TASK 'n' TICKS   (n from 1 to 65535)
************************************************************
*/
void OSTimeDly(UWORD ticks)
{
    UBYTE p;


    OS_ENTER_CRITICAL();
    p = OSTCBCur->OSTCBPrio;
    if ((OSRdyTbl[p >> 3] &= ~OSMapTbl[p & 0x07]) == 0) {
        OSRdyGrp &= ~OSMapTbl[p >> 3];
    }
    OSTCBCur->OSTCBDly = ticks;
    OS_EXIT_CRITICAL();
    OSSched();
}
/*
************************************************************
*                  PROCESS SYSTEM TICK
************************************************************
*/
void OSTimeTick(void)
{
    UBYTE   p;
    OS_TCB *ptcb;


    ptcb = OSTCBList;
    while (ptcb->OSTCBPrio != OS_LO_PRIO) {
        OS_ENTER_CRITICAL();
        if (ptcb->OSTCBDly != 0) {
            if (--ptcb->OSTCBDly == 0) {
                p                 = ptcb->OSTCBPrio;
                OSRdyGrp         |= OSMapTbl[p >> 3];
                OSRdyTbl[p >> 3] |= OSMapTbl[p & 0x07];
            }
        }
        OS_EXIT_CRITICAL();
        ptcb = ptcb->OSTCBNext;
    }
}
/*
************************************************************
*                GET TCB FROM FREE TCB LIST
************************************************************
*/
OS_TCB *OSTCBGetFree(void)
{
    OS_TCB *ptcb;


    OS_ENTER_CRITICAL();
    ptcb          = OSTCBFreeList;
    OSTCBFreeList = ptcb->OSTCBNext;
    OS_EXIT_CRITICAL();
    return (ptcb);
}