带优先权的时间片轮转

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1、#include#include#include#defineGET_INDOS0x34#defineGET_CRT_ERR0x5d06charfar*indos_ptr=0;charfar*crit_err_ptr=0;inttimecount=0;intcur;#defineFINISHED0#defineRUNNING1#defineREADY2#defineBLOCKED3#defineNTCB3voidinterrupt(*old_int8)();typedefint(far*codep

2、tr)(void);intcreate(char*name,codeptrcod,intstck,unsignedpri);voiddestroy(intid);voidover(void);voidinterruptswtch(void);voidInitDos(void);intDosBusy(void);voidinterruptmy_swtch(void);voidinterruptnew_int8(void);intfinished();intGetNextPsc();structTCB{unsignedchar*stack;unsign

3、edss;unsignedsp;charstate;charname[10];unsignedpri;}tcb[NTCB];typedefstruct{unsignedbp,di,si,ds,es,dx,cx,bx,ax,ip,cs,flags,off,seg;}int_regs;voidInitTCB(){inti;for(i=0;i

4、intcreate(char*name,codeptrcode,intstck,unsignedpri){/*TCB块申请*/intID;char*newspace;int_regs*regsAd;for(ID=0;ID

5、tck*sizeof(char)+sizeof(int_regs));regsAd->es=regsAd->ds=(unsigned)FP_SEG(newspace);regsAd->cs=(unsigned)FP_SEG(code);regsAd->ip=(unsigned)FP_OFF(code);regsAd->flags=0x200;regsAd->off=(unsigned)FP_OFF(over);regsAd->seg=(unsigned)FP_SEG(over);/*~初始化堆栈*//*初始化TCB*/tcb[ID].stack=n

6、ewspace;tcb[ID].ss=FP_SEG(newspace);tcb[ID].sp=FP_OFF(regsAd);tcb[ID].state=READY;strcpy(tcb[ID].name,name);tcb[ID].pri=pri;/*~初始化TCB*/returnID;}voiddestroy(intid){free(tcb[id].stack);tcb[id].state=FINISHED;}voidover(){destroy(cur);my_swtch();}voidinterruptmy_swtch(){intnextPc

7、s;nextPcs=GetNextPsc();disable();tcb[cur].ss=_SS;tcb[cur].sp=_SP;if(tcb[cur].state==RUNNING)tcb[cur].state=READY;cur=nextPcs;_SS=tcb[cur].ss;_SP=tcb[cur].sp;tcb[cur].state=RUNNING;timecount=0;enable();}voidinterruptnew_int8(){(*old_int8)();timecount++;if(timecount>tcb[cur].pri

8、){if(!DosBusy())my_swtch();}}intGetNextPsc(){intget=cur;while