#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <time.h>
#include <assert.h>
#include <stdint.h>
#include <ctype.h>
#include <limits.h>

#define MAX_LABEL_LENGTH 20
#define MAX_SYMBOL_COUNT 255
#define MAX_LINE_LENGTH 255
#define VALID_INSTR_CNT 28
#define PSEUDO_OP_COUNT 3

const char valid_op_codes[VALID_INSTR_CNT][8] = 
  {  
    "add", 
    "and", 
    "brn", 
    "brz", 
    "brp", 
    "brnz", 
    "brnp", 
    "brzp", 
    "br", 
    "brnzp", 
    "halt", 
    "jmp", 
    "jsr", 
    "jsrr", 
    "ldb", 
    "ldw", 
    "lea", 
    "nop", 
    "not", 
    "ret", 
    "lshf", 
    "rshfl", 
    "rshfa", 
    "rti", 
    "stb", 
    "stw", 
    "trap", 
    "xor"
  };

const char pseudo_op_codes[PSEUDO_OP_COUNT][8] = 
  {
    ".orig", 
    ".end", 
    ".fill"
  };

enum { 
  DONE, 
  OK, 
  EMPTY_LINE 
};


typedef struct{
	uint16_t address;
	char label[MAX_LABEL_LENGTH + 1];
} TableEntry;

TableEntry symbolTable[MAX_SYMBOL_COUNT];


/*
//////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////
*/

FILE* iFilePtr  = NULL;
FILE* oFilePtr  = NULL;
uint32_t curr_symbol_count = 0;

/*
//////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////
*/

uint32_t make_pass_one (void);
uint32_t make_pass_two (void);
uint32_t process_instruction (char *, char *, char *, 
			      char *, char *, uint16_t);
uint32_t readAndParse (FILE *, char *, char **, char **, 
		       char **, char **, char **, char **);
uint32_t is_opcode(char *);

/*
//////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////
*/

int main (int argc, char ** argv) {
  int retval=0;
  
  /* argc must be 3 for correct execution */ 
  if ( argc != 3 ) { 
    fprintf (stderr, "Usage: %s <source.asm> <output.obj>\n", argv[0]);
    retval = 4; 
    exit (retval);
  }
	
  iFilePtr = fopen(argv[1], "r"); 
  if (!iFilePtr) {
    fprintf(stderr, "Error: Cannot open input file %s\n", argv[1]);
    retval = 4; 
    exit (retval);
  }

  oFilePtr = fopen(argv[2], "w");	    
  if (!oFilePtr) {
    fprintf(stderr, "Error: Cannot open output file %s\n", argv[2]);
    retval = 4; 
    exit (retval);
  }
  
  retval = make_pass_one ();
  if (retval) {
    exit (retval);
  }
  
  /* rewind input file after first pass */
  if (fseek (iFilePtr, 0, SEEK_SET)) {
    retval = 4; 
    exit (retval);
  }

  retval = make_pass_two ();
  if (retval) {
    exit (retval);
  }
	
  fclose (iFilePtr); 
  fclose (oFilePtr);
		
  return (retval);
}


/*
//////////////////////////////////////////////////////////////////////////
//  Create Symbol Table in Pass 1
//////////////////////////////////////////////////////////////////////////
*/

uint32_t make_pass_one (void) {
  uint32_t retval;

  /* write code here */

  return retval;
}

/*
//////////////////////////////////////////////////////////////////////////
//  Generate Machine Instructions in Pass2
//////////////////////////////////////////////////////////////////////////
*/

uint32_t make_pass_two (void) {
  uint32_t retval;

  /* write code here */

  return retval;
}

/*
//////////////////////////////////////////////////////////////////////////
//  Write helper functions here (keep code modular)
//////////////////////////////////////////////////////////////////////////
*/