hey every one.. i get these error msgs with my code.. i just dont get.. it.. am i missing something
Code:cc -o clock clock.c clock.h cc: Error: clock.c, line 76: In this statement, "free_list_head" is not declared. (undeclared) free_list_head = (list)malloc(sizeof(struct list_item)); --------^ cc: Error: clock.c, line 97: In this statement, "total_ref" is not declared. (undeclared) total_ref++; ----------------^ cc: Error: clock.c, line 151: In this statement, "free_list_head" is not declared. (undeclared) if (free_list_head == free_list_head->prev) /* free list empty */ ------------^ cc: Error: clock.c, line 245: In this statement, "total_ref" is not declared. (undeclared) printf("\nProcess issued %d memory references\n", total_ref); ----------------------------------------------------------^Code:#include "clock.h" pt_entry pte[MAX_PAGE]; /* page table */ int mem_size; /* physical memory size list free_list_head; /* free list */ list res_set_head; /* resident set */ int total_fault = 0; /* total number of page faults int total_ref = 0; /* total number of memo /* main program: ** read in paramters, and open the input file ** start the simulation ** close the input file */ int main(int argc, char *argv[]) { FILE *stream; if (argc != 3) { printf("The format is: pager file_name memory_size.\n"); exit(1); } printf("File used %s, resident set size %d\n", argv[1], atoi(argv[2])); if ((stream = fopen(argv[1], "r")) == NULL) { perror("File open failed"); exit(1); } mem_size = atoi(argv[2]); start_simulation(stream); fclose(stream); } /* start_simulation: ** initialise the page table ** initialise the resident set, and the free list ** in the simulation loop ** 16-bit memory addresses representing the program trace are read ** the virtual address is resolved ie. physical frame for the virt ** the loop exits when it encounters the end of file ** free memory allocated for lists ** display statistics */ void start_simulation(FILE * stream) { char *addr_buf; int address; int i, n; list new_entry, current; /* initialise the page table */ for(i=0; i<MAX_PAGE;i++) { pte[i].frame = -1; pte[i].valid = 0; pte[i].dirty = 0; pte[i].in_mem = 0; pte[i].R = 0; } /* initialise the resident set - empty*/ res_set_head = (list)malloc(sizeof(struct list_item)); res_set_head->next = res_set_head; res_set_head->prev = res_set_head; /* initialise free list - all physical pages*/ free_list_head = (list)malloc(sizeof(struct list_item)); free_list_head->next = free_list_head; free_list_head->prev = free_list_head; current = free_list_head; for(i=0; i<mem_size;i++) { new_entry = (list)malloc(sizeof(struct list_item)); current->next = new_entry; new_entry->prev = current; new_entry->next = free_list_head; new_entry->frame = i; current = new_entry; free_list_head->prev = current; } /* main simulation loop */ while( (n = fscanf(stream, "%x", &address)) != -1) { resolve(address); total_ref++; } free_mem(free_list_head); free_mem(res_set_head); display_stats(); return; } /* resolve: ** resolve address reference ** if page table entry valid - do nothing ** if page table entry invalid - find a physical frame for this pa ** and update pte for the page */ void resolve(int address) { unsigned short frame_alloc; int virt_page; static int disp_counter = 0; virt_page = address >> 8; if (pte[virt_page].valid == 1) { /* depending on the algorithm used you may need to manipulate various fields in the page table entry for the page */ pte[virt_page].R = 1; } else { frame_alloc = find_frame(); pte[virt_page].valid = 1; pte[virt_page].frame = frame_alloc; pte[virt_page].R = 1; total_fault++; } } /* find_frame: ** if free list is empty find a victim frame ** else detach the last frame of the free list and attach it ** to the resident set ** return frame number */ unsigned short find_frame() { unsigned short frame; list current, new_tail; if (free_list_head == free_list_head->prev) /* free list empty */ frame = find_victim(); else { new_tail = free_list_head->prev->prev; new_tail->next = free_list_head; current = free_list_head->prev; free_list_head->prev = new_tail; to_resident_set(current); frame = current->frame; } return frame; } /* to_resident_set: ** attach a list entry at the end of resident set */ void to_resident_set(list current) { list tail; tail = res_set_head->prev; tail->next = current; current->next = res_set_head; current->prev = tail; res_set_head->prev = current; } /* find_victim: ** As you can see I simply take the first page frame from the resident set list ** This implements the FIFO replacement strategy. Your task is to replace it wi ** a more efficient strategy. */ unsigned short find_victim() { unsigned short frame; //list current; int i, found = 0; static list curr = NULL; if(curr == NULL) curr = res_set_head; while(found != 1) { frame = curr->frame; for(i=0; i<MAX_PAGE; i++) { if(pte[i].frame == frame && pte[i].R == 0) { found = 1; pte[i].valid = 0; pte[i].frame = -1; pte[i].R = 0; //printf("\n Page %X is evicted\n", i); break; } else pte[i].R = 0; } curr = curr->next; } return frame; } /* invalidate: ** invalidate the page table entry for the victim page */ void invalidate(unsigned short frame) { int i; for(i=0;i<MAX_PAGE;i++) { if (pte[i].frame == frame && pte[i].valid == 1) { pte[i].valid = 0; pte[i].frame = -1; break; } } } /* display_stats: ** This is very basic, you may want to make it more sophisticated, ** for example save the data from multiple runs into a file for ** comparison etc */ void display_stats() { printf("\nProcess issued %d memory references\n", total_ref); printf("Process triggered %d page faults\n", total_fault); printf("Page fault rate is %d percent\n",((total_fault*100)/total_ref)); } /* free_mem: ** free memory allocated to the list */ void free_mem(list head) { list current,tail; tail = head->prev; current = head; while (current->prev != tail) { current = current->next; free(current->prev); } }
