didnt want to do a title like that but i am running out of time and i need to get this working.
Hi all, I have to finish an assignment today that takes in two command line arguments for a code file and a memory file.
The code file contains a number specifying how many assembly instructions are in the code, the memory file contains the initial memory contents.
The program must simulate the assembly code.
It has to be done in C and I am more use to C++.
Here are a few examples of stupid errors that I think are right (remember it's been a while since I used any standard library functions as I use all my own now)
memory.txt contents:
0 0 0 0 12 0 16 0 24 0 2 0 0 0 0 0 4 3 1 8
now i open the file memory.txt and start reading in like so
for(i = 0; i < 20; i++)
{
fscanf(file2, "%d ",&memory);
}
there are only 20 ints to store the memory.
but my output shows that i read in all 0's except memory[8] has the value 20, what's up with that?
Also when reading the code file i use:
fscanf(file1, "%d", &numOfInstructions);
to read in an int.
But when I use this value later in loops it act silly e.g.
for(i = 0; i < numOfInstructions; i++)
{
//why do i need this?
if(i > 7)
break;
//read line from file
strcpy(instructions.string, getLine(file1));
}
if i don't have that if statement the code crashes but quite clearly i shouldnt need it.
there is stuff like this happening all over my code and i only have about an hour to finish it (i think that all my program is mostly right or at least has the right idea going)
here's my program anyway incase you need to see anything else to spot what's going on (also i am using vc++ .net console application)
note the code may look dodgy and doesn't reflect my usual style
// emulator.cpp
//
#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int registers[8];
int memory[20];
struct instructionString
{
char string[80];
};
int programCounter = 0;
struct instruction
{
char name[10];
int op1, op2;
char operand1[10];
char operand2[10];
bool op2Register; //used to flag if op2 is a register or a value
};
char *getLine(FILE *file)
{
char *s;
char tok = getc(file);
int count = 0;
s = (char*)malloc(80);
while(tok != '\n')
{
s[count++] = tok;
tok = getc(file);
}
s[count] = '\0';
return s;
}
struct instruction instTable[20];
struct instructionString instructions[20];
int main(int argc, char *argv[])
{
char *fileName1;
char *fileName2;
int i;
int numOfInstructions;
//initialise register
for(i = 0; i < 8; i++)
{
registers = 0;
}
//initialise memory
for(i = 0; i < 20; i++)
{
memory = 0;
}
fileName1 = argv[1];
fileName2 = argv[2];
FILE *file1;
FILE *file2;
if((file1 = fopen(fileName1, "r")) == NULL)
{ printf("Can't open file: %s\nProgram ending", fileName1);
return 0;
}
if((file2 = fopen(fileName2, "r")) == NULL)
{ printf("Can't open file: %s\nProgram ending", fileName2);
return 0;
}
//read initial memory values from file2
for(i = 0; i < 20; i++)
{
fscanf(file2, "%d ",&memory);
}
//read number of assembler instructions from file 1
fscanf(file1, "%d", &numOfInstructions);
for(i = 0; i < numOfInstructions; i++)
{
//why do i need this?
if(i > 7)
break;
//read line from file
strcpy(instructions.string, getLine(file1));
}
//close files
fclose(file1);
fclose(file2);
//split each instruction into individual parts
//process each instruction
for(i = 0; i < numOfInstructions; i++)
{
if(i > 6)
break;
//get instruction name
int j = 0,k = 0;
while(instructions.string[j] != ' ')
{
instTable.name[k] = instructions.string[j];
j++; k++;
}
instTable.name[k] = '\0';
j++; k = 0;
//get first operand
while(instructions.string[j] != ' ')
{
instTable.operand1[k] = instructions.string[j];
j++; k++;
}
instTable.operand1[k] = '\0';
j++; k = 0;
//get 2nd operand
while(instructions.string[j] != ' ')
{
instTable.operand2[k] = instructions.string[j];
j++; k++;
}
instTable.operand2[k] = '\0';
j++; k = 0;
//convert 1st operand into a register number
instTable.op1 = atoi(&instTable.operand1[1]);
//if(operand2[0] != r then convert the whole string to a number else
if(instTable.operand1[0] == 'R')
{
char temp[9];
memcpy(temp, &instTable.operand1[1], strlen(instTable.operand1)-1);
instTable.op2Register = true;
}
else
{
instTable.op2 = atoi(&instTable.operand2[1]);
instTable.op2Register = false;
}
}
//main loop simulator
while(programCounter < 20)
{
printf("here1");
//printf("%d", programCounter);
//programCounter++;
if(strcmp(instTable[programCounter].name, "load") == 0)
{
printf("here2");
if(instTable[programCounter].op2Register)
registers[instTable[programCounter].op1] = registers[instTable[programCounter].op2];
programCounter++;
}
if(strcmp(instTable[programCounter].name, "add") == 0)
{
printf("here2");
if(instTable[programCounter].op2Register)
registers[instTable[programCounter].op1] += registers[instTable[programCounter].op2];
else
registers[instTable[programCounter].op1] += memory[instTable[programCounter].op2];
programCounter++;
}
if(strcmp(instTable[programCounter].name, "sub") == 0)
{
printf("here3");
if(instTable[programCounter].op2Register)
registers[instTable[programCounter].op1] -= registers[instTable[programCounter].op2];
else
registers[instTable[programCounter].op1] -= memory[instTable[programCounter].op2];
programCounter++;
}
if(strcmp(instTable[programCounter].name, "loadind") == 0)
{
printf("here4");
if(instTable[programCounter].op2Register)
registers[instTable[programCounter].op1] = memory[registers[instTable[programCounter].op2]];
programCounter++;
}
if(strcmp(instTable[programCounter].name, "storeind") == 0)
{
printf("here5");
if(instTable[programCounter].op2Register)
memory[registers[instTable[programCounter].op1]] = registers[instTable[programCounter].op2];
programCounter++;
}
}
printf("here8");
for(int i = 0; i < 8; i++)
{
printf("R%d = %d\n", i, registers);
}
for(int i = 0; i < 20; i++)
{
printf("mem location %d = %d\n", i, registers);
}
//end
return 0;
}
also here is the code.txt file
8
load R1 R8
add R1 16
loadind R2 R1
add R1 8
loadind R3 R1
add R3 R2
sub R1 4
storeind R3 R1
any help is appreciated.
[Edited by - JinJo on November 12, 2004 9:18:54 AM]
