simulator - Y86 Processor in C help! Stuck on the loader.c file -
this gonna bit of large question (at least me seems) bear me. we're making y86 simulator in c , part of assignment supposed open file, load memory, perform dump, , exit. main method provided these things, we're supposed create loader.c , loader.h files loading. load function returns true(1) if load successful (input file free of errors) , false(0) otherwise. right now, i'm stuck on load function, , think issue on around line 58-67 of loader.c. i'm not calling method properly, cannot figure out how format numbers properly. first time i'm working in c, it's still rather confusing me. if needed can provide more code. far i've included loader.c, loader.h, memory.c, , memory.h. bool.h included, it's typedef true-false figured leave out. apologize if bit much, i'm stumped , don't know else go. thank in advance given, appreciated!
loader.c:
1 #include <stdio.h> 2 #include <string.h> 3 #include "loader.h" 4 #include "bool.h" 5 #include "memory.h" 6 7 bool checkaddressformat (char addressarray[]); 8 bool checkdataformat(char dataarray[]); 9 bool isdigit(char character); 10 bool checkline(char inputline[]); 11 12 int load(int argc, char *argv[]){ 13 14 if (argc != 2){ 15 printf("file opening failed \nusage: yess <filename>.yo\n"); 16 return 0; 17 } 18 else{ 19 //checks files exist 20 file* file = fopen(argv[1], "r" ); 21 char* ext; 22 ext = strrchr(argv[1], '.'); //grab extension 23 if (file == 0 || strcmp(ext,".yo") != 0) { 24 printf("file opening failed \nusage: yess <filename>.yo\n"); 25 return 0; 26 } 27 else{ 28 char inputline[250]; //the current line being used 29 int intline[250]; 30 int ch; 31 int i; 32 int j; 33 int k; 34 int m; 35 bool linecheck; 36 bool memerror = false; 37 int byteaddress; 38 int linenumber = 1; 39 40 ch = fgetc(file); //grab first character 41 while (!feof(file)) //while file not empty 42 { 43 while(ch != '\n'){ 44 inputline[i] = ch; 45 intline[i] = ch; 46 ch = fgetc(file); 47 } 48 char addressstring[4]; 49 addressstring[3] = '\0'; 50 for(j = 0; j < 3; j++){ //creates char array of address on current line. 51 addressstring[j] = inputline[j+4]; 52 } 53 byteaddress = atoi(addressstring); //turns array int pass putbyte 54 55 unsigned char datastring[12]; 56 for(k = 0; k < 12; k++) { 57 datastring[k] = (unsigned char)intline[k+9]; 58 } 59 60 if(checkline(inputline) == false){ 61 printf("error on line %d:\n",linenumber); 62 printf("%s\n",inputline); 63 return 0; 64 } 65 66 else{ 67 for(m = 0; m < 250; m++) { 68 putbyte(byteaddress, datastring[m], &memerror); 69 } 70 printf("call putbyte"); 71 } 72 73 for(i = 0; < 250; i++){ 74 inputline[i] = ' '; 75 intline[i] = ' '; 76 } 77 printf("clear arrays"); 78 linenumber++; 79 ch = fgetc(file); 80 } 81 } 82 close(file); 83 } 84 return 1; 85 } 86 87 bool checkline(char inputline[]){ 88 89 if(checkdataformat(inputline) == false || checkaddressformat(inputline) == false){ 90 return false; 91 } 92 else if(inputline[22] != '|'){ 93 return false; 94 } 95 else { 96 return true; 97 } 98 99 } 100 bool checkdataformat(char dataarray[]) { 101 int i; 102 bool temp; 103 int counter = 0; 104 for(i = 9; <= 20; i++) { 105 temp = isdigit(dataarray[i]); 106 if(temp == true){ 107 counter++; 108 } 109 } 110 if(counter > 12){ 111 return false; 112 } 113 else{ 114 return true; 115 } 116 } 117 118 bool checkaddressformat(char addressarray[]) { 119 if(isdigit(addressarray[2]) == false || isdigit(addressarray[4]) == false || isdigit(addressarray[5]) == false || isdigit(addressarray[6]) == false) 120 return false; 121 if(addressarray[3] != 'x') 122 return false; 123 if(addressarray[7] != ':') 124 return false; 125 else 126 return true; 127 } 128 129 bool isdigit(char character) { 130 if(character == '0' || character == '1' || character == '2' || character == '3' || 131 character == '4' || character == '5' || character == '6' || character == '7' || 132 character == '8' || character == '9' || character == 'a' || character == 'b' || 133 character == 'c' || character == 'd' || character == 'e' || character == 'f') 134 return true; 135 else 136 return false; 137} 138 loader.h:
1 #ifndef loader_h 2 #define loader_h 3 4 int load(int argc, char *argv[]); 5 6 #endif memory.c:
1 #define memsize 1024 //1024 words of memory 2 #ifndef memory_h 3 #define memory_h 4 #include "bool.h" 5 6 static unsigned int memarray[memsize]; 7 8 9 unsigned int fetch(int address, bool * memerror){ 10 11 if(address < 0 || address > 1024) 12 (*memerror) = true; 13 else{ 14 (*memerror) = false; 15 return memarray[address]; 16 } 17 } 18 19 void store(int address, unsigned int value, bool * memerror){ 20 if(address < 0 || address > 1024) 21 (*memerror) = true; 22 else{ 23 (*memerror) = false; 24 memarray[address] = value; 25 } 26 } 27 28 unsigned char getbyte(int byteaddress, bool * memerror){ 29 if(byteaddress < 0 || byteaddress > 4095){ 30 (*memerror) = true; 31 return 0; 32 } 33 else{ 34 (*memerror) = false; 35 int wordaddress = fetch((byteaddress/4), memerror); 36 char * x = (char*)&wordaddress; 37 char temp = x[(byteaddress%4)]; 38 return temp; 39 } 40 } 41 void putbyte(int byteaddress, unsigned char value, bool * memerror){ 42 if(byteaddress < 0 || byteaddress > 4095) 43 (*memerror) = true; 44 else{ 45 (*memerror) = false; 46 int wordaddress = fetch((byteaddress/4), memerror); 47 char * x = (char*)&wordaddress; 48 x[(byteaddress%4)] = value; 49 store(byteaddress/4, wordaddress, memerror); 50 } 51 } 52 void clearmemory(){ 53 54 int i; 55 for(i=0;i<memsize;i++){ 56 memarray[i] = 0; 57 } 58 59 } 60 //address must multiple of 4 61 unsigned int getword(int byteaddress, bool * memerror){ 62 63 if(byteaddress < 0 || byteaddress > 4095 || (byteaddress%4) != 0){ 64 (*memerror) = true; 65 return 0; 66 } 67 else{ 68 int word = fetch(byteaddress/4, memerror); 69 (*memerror) = false; 70 return word; 71 } 72 } 73 //address must multiple of 4 74 void putword(int byteaddress, unsigned int value, bool * memerror){ 75 76 if(byteaddress < 0 || byteaddress > 4095 || (byteaddress%4) != 0){ 77 (*memerror) = true; 78 } 79 else{ 80 store((byteaddress/4), value, memerror); 81 (*memerror) = false; 82 } 83 84 85 } 86 #endif 87 88 memory.h:
1 #define memsize 1024 //1024 words of memory 2 #ifndef memory_h 3 #define memory_h 4 5 unsigned int fetch(int address, bool * memerror); 6 void store(int address, unsigned int value, bool * memerror); 7 unsigned char getbyte(int byteaddress, bool * memerror); 8 void putbyte(int byteaddress, unsigned char value, bool * memerror); 9 void clearmemory(); 10 unsigned int getword(int byteaddress, bool * memerror); 11 void putword(int byteaddress, unsigned int value, bool * memerror); 12 #endif
you should examine arrays then. far, common error either (a) aren't long enough, or (b) calling function assumes string/array 0 (null) terminated, 0 hasn't been added. string in c null terminated c string functions work.
a couple of example trouble spots...
47 char addressstring[3]; 48 for(j = 0; j < 3; j++){ //creates char array of address on current line. 49 addressstring[j] = inputline[j+4]; 50 } 51 byteaddress = atoi(addressstring); //turns array int pass putbyte you copying 3 bytes input line addressstring. array has enough space hold characters , has no null termination. subsequent atoi call can go off never-never land (potential segfault).
here, datastring array of characters:
53 unsigned char datastring[12]; 54 for(k = 0; k < 12; k++) { 55 datastring[k] = (unsigned char)intline[k+9]; 56 } 57 here, you're treating datastring if single character:
58 unsigned char data = datastring; 59 60 if(checkline(inputline) == false){ 61 printf("error on line %d:\n",linenumber); 62 printf("%s\n",inputline); 63 return 0; 64 } 65 66 else{ 67 putbyte(byteaddress, datastring, &memerror); 68 } this may not cause segfault, incorrect.
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