教程: 建立一个属于自己的AVR的RTOS (作者：hjc800323）

zengqh1979

to 16楼：

2\请问void OSSched(void) 中 

OSNextTaskID < OS_TASKS && !(OSRdyTbl & (0x01<<OSNextTaskID)); 这条具体的意思,哪位大侠帮我分解一下 



我也正在研究这个，是看了反汇编程序才看懂的，

for (OSNextTaskID=0;(OSNextTaskID < OS_TASKS) && !(OSRdyTbl & (0x01<<OSNextTaskID));OSNextTaskID++);  //进行任务调度  

这条语句的作用就是查找当前任务表OSRdyTbl中最高优先级别的任务，从bit0位开始查询，直到查完所有任务为止；

汇编程序：

//查找任务

    unsigned char OSNextTaskID;                             

    for ( OSNextTaskID = 0;                                 

     bbc:        40 e0               ldi        r20, 0x00        ; 0

     bbe:        22 2d               mov        r18, r2

     bc0:        33 27               eor        r19, r19

     bc2:        61 e0               ldi        r22, 0x01        ; 1

     bc4:        70 e0               ldi        r23, 0x00        ; 0

     bc6:        20 fd               sbrc        r18, 0

     bc8:        0e c0               rjmp        .+28             ; 0xbe6 <_Z7OSSchedv+0x68>

     bca:        4f 5f               subi        r20, 0xFF        ; 255

     bcc:        45 30               cpi        r20, 0x05        ; 5

     bce:        58 f4               brcc        .+22             ; 0xbe6 <_Z7OSSchedv+0x68>

     bd0:        c9 01               movw        r24, r18

     bd2:        04 2e               mov        r0, r20

     bd4:        02 c0               rjmp        .+4              ; 0xbda <_Z7OSSchedv+0x5c>

     bd6:        95 95               asr        r25

     bd8:        87 95               ror        r24

     bda:        0a 94               dec        r0

     bdc:        e2 f7               brpl        .-8              ; 0xbd6 <_Z7OSSchedv+0x58>

     bde:        86 27               eor        r24, r22

     be0:        97 27               eor        r25, r23

     be2:        80 fd               sbrc        r24, 0

     be4:        f2 cf               rjmp        .-28             ; 0xbca <_Z7OSSchedv+0x4c>

          OSNextTaskID < OS_MAX_TASKS && !(OSRdyTbl & (0x01<<OSNextTaskID));

          OSNextTaskID++);

      OSTaskRunningPrio = OSNextTaskID ;

     be6:        34 2e               mov        r3, r20