暂停在cmp: ![实验楼](https://dn-simplecloud.shiyanlou.com/3918281540386284164-wm) i保存在0x3004 ![实验楼](https://dn-simplecloud.shiyanlou.com/3918281540386402375-wm) ldtr保存在0x0068=0000000001101000, 即13号位置 gdtr保存在0x00005cb8 ![实验楼](https://dn-simplecloud.shiyanlou.com/3918281540386591042-wm) gdt表： ![实验楼](https://dn-simplecloud.shiyanlou.com/3918281540386686951-wm) 所以ldt表在0x00005cb8+13*8=0x00005D20 ![实验楼](https://dn-simplecloud.shiyanlou.com/3918281540386893372-wm) 与sreg的输出一致。组合为0x00f9c2d0,如图为ldt前4项。 ds现是0x0017=0000000000010111，索引为2，即0x00003fff和0x10c0f300 与sreg相符则ds段的起始位置在0x10000000 ds:0x3004为0x10003004,验证如下 ![实验楼](https://dn-simplecloud.shiyanlou.com/3918281540387683226-wm) 意义是页目录号64，页号3，偏移4 CR3在0x00000000 ![实验楼](https://dn-simplecloud.shiyanlou.com/3918281540387791093-wm) 页目录表： ![实验楼](https://dn-simplecloud.shiyanlou.com/3918281540387883994-wm) 第65个页目录项：0x00f97027 ![实验楼](https://dn-simplecloud.shiyanlou.com/3918281540387939205-wm) 所以在0x00f97000+3*4： ![实验楼](https://dn-simplecloud.shiyanlou.com/3918281540388168742-wm) 所以最后的物理地址为0x00f96000+0x0004： ![实验楼](https://dn-simplecloud.shiyanlou.com/3918281540388282557-wm) 结果正确。 ``` setpmem 0x00f96004 4 0 ``` ![实验楼](https://dn-simplecloud.shiyanlou.com/3918281540388416757-wm) linux里停止运行了。 ubuntu上的程序： producer.c ``` #include #include #include #include #include #include #include #include const int itemNum=500; const int bufSize=10; int main(){ int i; int shmid; sem_t *empty,*full,*mutex; int* p; int fullvalue; sem_unlink("empty"); sem_unlink("full"); sem_unlink("mutex"); empty=sem_open("empty",O_CREAT|O_EXCL,0666,10); full=sem_open("full",O_CREAT|O_EXCL,0666,0); mutex=sem_open("mutex",O_CREAT|O_EXCL,0666,1); shmid=shmget(1,(bufSize)*sizeof(int),IPC_CREAT|0777); if(shmid==-1){ perror("shmget error\n"); } p=(int*)shmat(shmid,NULL,SHM_EXEC); for(i=0;i #include #include #include #include #include #include #include #include const int itemNum=500; const int bufSize=10; int main(){ int i; int shmid; sem_t *empty,*full,*mutex; int* p; int data; int fullvalue; freopen("out.txt","w",stdout); printf("start\n"); fflush(stdout); empty=sem_open("empty",0); full=sem_open("full",0); mutex=sem_open("mutex",0); if(empty==NULL||full==NULL||mutex==NULL){ printf("sem_open error\n"); fflush(stdout); return -1; } printf("sem opened\n"); fflush(stdout); shmid=shmget(1,(bufSize)*sizeof(int),IPC_CREAT|0777); if(shmid==-1){ printf("shmget error\n"); } p=(int*)shmat(shmid,NULL,SHM_EXEC); printf("begin consume\n"); fflush(stdout); for(i=0;i #include #include #include #define shmSize 10 struct shm_table{ unsigned int key; unsigned int size; unsigned long addr; int used; }shm_table[shmSize]={0}; int sys_shmget(unsigned int key, unsigned int size){ int i; unsigned long tmp,addr; if(size>PAGE_SIZE){ return -1; } for(i=0;ibrk+current->start_code); return (void*)current->brk; } ``` linux0.11上的生产者消费者： producer.c ``` #define __LIBRARY__ #include #include #include #include #include _syscall2(sem_t *, sem_open, const char*,name,unsigned int,value); _syscall1(int,sem_wait,sem_t *,sem); _syscall1(int,sem_post,sem_t *,sem); _syscall1(int,sem_unlink,const char *,name); _syscall2(int,shmget,unsigned int,key,unsigned int,size); _syscall1(void*,shmat,int,shmid); const int itemNum=500; const int bufSize=10; int main(){ int i; int shmid; sem_t *empty,*full,*mutex; int *p; int fullvalue; empty=sem_open("empty",10); full=sem_open("full",0); mutex=sem_open("mutex",1); shmid=shmget(1,(bufSize)*sizeof(int)); if(shmid==-1){ perror("shmget error\n"); return -1; } p=(int*)shmat(shmid); printf("produce begin\n"); fflush(stdout); for(i=0;i #include #include #include #include _syscall2(sem_t *, sem_open, const char*,name,unsigned int,value); _syscall1(int,sem_wait,sem_t *,sem); _syscall1(int,sem_post,sem_t *,sem); _syscall1(int,sem_unlink,const char *,name); _syscall2(int,shmget,unsigned int,key,unsigned int,size); _syscall1(void*,shmat,int,shmid); const int itemNum=500; const int bufSize=10; int main(){ int i; int shmid; sem_t *empty,*full,*mutex; int* p; int data; int fullvalue; freopen("nout.txt","w",stdout); printf("start\n"); fflush(stdout); empty=sem_open("empty",10); full=sem_open("full",0); mutex=sem_open("mutex",1); if(empty==NULL||full==NULL||mutex==NULL){ printf("sem_open error\n"); fflush(stdout); return -1; } printf("sem opened\n"); fflush(stdout); shmid=shmget(1,(bufSize)*sizeof(int)); if(shmid==-1){ printf("shmget error\n"); return -1; } p=(int*)shmat(shmid); printf("begin consume\n"); fflush(stdout); for(i=0;iLDT->ds->线性地址->物理地址 2.虚拟地址不变。而线性地址和物理地址变了。再运行一次，会从0x10003004变成0x14003004，正好多了64M，对应了nr*64M的线性地址分配方法。

“操作系统原理与实践”实验报告