V  A,@R1
        MOV  @R0,A
               
        ;OSPrioCur = OSPrioHighRdy  使用这两个变量主要目的是为了使指针比较变为字节比较，以便节省时间。
        MOV  R0,#OSPrioCur
    MOV  R1,#OSPrioHighRdy
    MOV  A,@R1
        MOV  @R0,A
       
        LJMP OSCtxSw_in
;-------------------------------------------------------------------------
        RSEG ?PR?OSIntCtxSw?OS_CPU_A
       
OSIntCtxSw:

        ;调整SP指针去掉在调用OSIntExit(),OSIntCtxSw()过程中压入堆栈的多余内容
        ;SP=SP-4

        MOV  A,SP
        CLR  C
        SUBB A,#4
        MOV  SP,A
       
        LJMP OSIntCtxSw_in
;-------------------------------------------------------------------------
        CSEG AT 000BH    ;OSTickISR
        LJMP OSTickISR   ;使用定时器0
        RSEG ?PR?OSTickISR?OS_CPU_A

OSTickISR:       
       
        USING 0       
        PUSHALL
       
        CLR  TR0
        MOV  TH0,#70H    ;定义Tick=50次/秒(即0.02秒/次)
        MOV  TL0,#00H    ;OS_CPU_C.C  和  OS_TICKS_PER_SEC
        SETB TR0
       
        LCALL _?OSIntEnter
        LCALL _?OSTimeTick
        LCALL _?OSIntExit
        POPALL       
        RETI
;-------------------------------------------------------------------------
        CSEG AT 0023H    ;串口中断
        LJMP SerialISR   ;工作于系统态，无任务切换。
        RSEG ?PR?_?serial?OS_CPU_A
       
SerialISR:
       
        USING 0       
        PUSHALL
        CLR  EA
        LCALL _?serial       
        SETB EA
        POPALL       
        RETI
;-------------------------------------------------------------------------
        END
;-------------------------------------------------------------------------

文件名 : OS_CPU_C.C

void *OSTaskStkInit (void (*task)(void *pd), void *ppdata, void *ptos, INT16U opt) reentrant
{   
    OS_STK *stk;

    ppdata = ppdata;
    opt    = opt;                           //opt没被用到，保留此语句防止告警产生   
    stk    = (OS_STK *)ptos;                //用户堆栈最低有效地址
    *stk++ = 15;                            //用户堆栈长度
    *stk++ = (INT16U)task & 0xFF;           //任务地址低8位
    *stk++ = (INT16U)task >> 8;             //任务地址高8位   
    *stk++ = 0x00;                          //PSW
    *stk++ = 0x0A;                          //ACC
    *stk++ = 0x0B;                          //B
    *stk++ = 0x00;                          //DPL
    *stk++ = 0x00;                          //DPH
    *stk++ = 0x00;                          //R0
    *stk++ = 0x01;                          //R1
    *stk++ = 0x02;                          //R2
    *stk++ = 0x03;                          //R3
    *stk++ = 0x04;                          //R4
    *stk++ = 0x05;                          //R5
    *stk++ = 0x06;                          //R6
    *stk++ = 0x07;                          //R7
                                            //不用保存SP，任务切换时根据用户堆栈长度计算得出。   
    return ((void *)ptos);
}

#if OS_CPU_HOOKS_EN
void OSTaskCreateHook (OS_TCB *ptcb) reentrant
{
    ptcb = ptcb;                       /* Prevent compiler warning                                     */
}

void OSTaskDelHook (OS_TCB *ptcb) reentrant
{
    ptcb = ptcb;                       /* Prevent compiler warning                                     */
}

void OSTimeTickHook (void) reentrant
{
}
#endif

//初始化定时器0
void InitTimer0(void) reentrant
{
    TMOD=TMOD&0xF0;
    TMOD=TMOD0x01;    //模式1(16位定时器)，仅受TR0控制
    TH0=0x70;    //定义Tick=50次/秒(即0.02秒/次)
    TL0=0x00;    //OS_CPU_A.ASM  和  OS_TICKS_PER_SEC
    ET0=1;       //允许T0中断
    TR0=1;  
}

文件名 : YY.C

#include

#define MAX_STK_SIZE 64

void TaskStartyya(void *yydata) reentrant;
void TaskStartyyb(void *yydata) reentrant;
void TaskStartyyc(void *yydata) reentrant;

OS_STK TaskStartStkyya[MAX_STK_SIZE+1];//注意：我在ASM文件中设置?STACK空间为40H即64，不要超出范围。
OS_STK TaskStartStkyyb[MAX_STK_SIZE+1];//用户栈多一个字节存长度
OS_STK TaskStartStkyyc[MAX_STK_SIZE+1];

void main(void)
{
    OSInit();
   
    InitTimer0();
    InitSerial();
    InitSerialBuffer();
   
    OSTaskCreate(TaskStartyya, (void *)0, &TaskStartStkyya[0],2);
    OSTaskCreate(TaskStartyyb, (void *)0, &TaskStartStkyyb[0],3);
    OSTaskCreate(TaskStartyyc, (void *)0, &TaskStartStkyyc[0],4);
   
    OSStart();
}

void TaskStartyya(void *yydata) reentrant
{
    yydata=yydata;
    clrscr();
    PrintStr("\n\t\t*******************************\n");
    PrintStr("\t\t*     Hello! The world.       *\n");
    PrintStr("\t\t*******************************\n\n\n");
   
    for(;;){
        PrintStr("\tAAAAAA111111 is active.\n");
        OSTimeDly(OS_TICKS_PER_SEC);   
    }   
}

void TaskStartyyb(void *yydata) reentrant
{
    yydata=yydata;
   
    for(;;){
        PrintStr("\tBBBBBB333333 is active.\n");
        OSTimeDly(3*OS_TICKS_PER_SEC);   
    }   
}

void TaskStartyyc(void *yydata) reentrant
{
    yydata=yydata;
   
    for(;;){
        PrintStr("\tCCCCCC666666 is active.\n");
        OSTimeDly(6*OS_TICKS_PER_SEC);   
    }   
}

* - 本贴最后修改时间：2003-5-29 11:25:08 修改者：gdtyy
* - 修改原因：+

作者信箱    asdjf@163.com  
 
 
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