/*
 *  va_optimizer.c - Brute force search for optimum vertical adder
 *
 *  T. Scott Dattalo
 *   NOV98
 */


enum INSTRUCTIONS
{

  NOP,

  MOVWF_r,
  MOVFW_r,
  ANDWF_r,
  ANDFW_r,
  IORWF_r,
  IORFW_r,
  XORWF_r,
  XORFW_r,
  COMF_r,
  COMF_rw,

  MOVWF_t,
  MOVFW_t,
  ANDWF_t,
  ANDFW_t,
  IORWF_t,
  IORFW_t,
  XORWF_t,
  XORFW_t,
  COMF_t,
  COMF_tw,

  MOVWF_k,
  MOVFW_k,
  ANDWF_k,
  ANDFW_k,
  IORWF_k,
  IORFW_k,
  XORWF_k,
  XORFW_k,
  COMF_k,
  COMF_kw,

  CLRF_t,
  XORLW_ff,

  TOTAL_INSTRUCTIONS
};


char * opcodes[]=
{
  "NOP",

  "MOVWF_r",
  "MOVFW_r",
  "ANDWF_r",
  "ANDFW_r",
  "IORWF_r",
  "IORFW_r",
  "XORWF_r",
  "XORFW_r",
  "COMF_r",
  "COMF_rw",

  "MOVWF_t",
  "MOVFW_t",
  "ANDWF_t",
  "ANDFW_t",
  "IORWF_t",
  "IORFW_t",
  "XORWF_t",
  "XORFW_t",
  "COMF_t",
  "COMF_tw",

  "MOVWF_k",
  "MOVFW_k",
  "ANDWF_k",
  "ANDFW_k",
  "IORWF_k",
  "IORFW_k",
  "XORWF_k",
  "XORFW_k",
  "COMF_k",
  "COMF_kw",

  "CLRF_t",
  "XORLW_ff",

  "last"
};


#define PROGRAM_SIZE  6

unsigned int program[PROGRAM_SIZE];

int main(int argc, char ** argv)
{

  unsigned int 
    k,
    r,
    w,
    t,
    i,
    current_address,
    looping,
    count,
    done;

  printf("vertical adder optimizer\n");

  printf("%s\n",opcodes[0]);

  /* Initialize the program: */

  for(i = 0; i<PROGRAM_SIZE; i++)
    program[i] = NOP;

  for(i=0; i<TOTAL_INSTRUCTIONS; i++)
    printf("%s  ",opcodes[i]);


  current_address = 0;
  done = 0;
  count = 0;

  do
    {
      k = 0xf0;    /* The constant */
      r = 0xcc;    /* The register */
      w = 0xaa;    /* The carry in */

      t = 0x0;

      /* Execute the program */

      for(i = 0; i<PROGRAM_SIZE; i++)
	{
	  switch (program[i])
	    {
	    case NOP:
	      break;

	    case MOVWF_r: 
	      r = w;
	      break;

	    case MOVFW_r:
	      w = r;
	      break;

	    case ANDWF_r:
	      r &= w;
	      break;

	    case ANDFW_r:
	      w &= r;
	      break;

	    case XORWF_r:
	      r ^= w;
	      break;

	    case XORFW_r:
	      w ^= r;
	      break;

	    case IORWF_r:
	      r |= w;
	      break;

	    case IORFW_r:
	      w |= r;
	      break;

	    case COMF_r:
	      r = ~r;
	      break;

	    case COMF_rw:
	      w = ~r;
	      break;



	    case MOVWF_t: 
	      t = w;
	      break;

	    case MOVFW_t:
	      w = t;
	      break;

	    case ANDWF_t:
	      t &= w;
	      break;

	    case ANDFW_t:
	      w &= t;
	      break;

	    case XORWF_t:
	      t ^= w;
	      break;

	    case XORFW_t:
	      w ^= t;
	      break;

	    case IORWF_t:
	      t |= w;
	      break;

	    case IORFW_t:
	      w |= t;
	      break;

	    case COMF_t:
	      t = ~t;
	      break;

	    case COMF_tw:
	      w = ~t;
	      break;



	    case MOVWF_k: 
	      k = w;
	      break;

	    case MOVFW_k:
	      w = k;
	      break;

	    case ANDWF_k:
	      k &= w;
	      break;

	    case ANDFW_k:
	      w &= k;
	      break;

	    case XORWF_k:
	      k ^= w;
	      break;

	    case XORFW_k:
	      w ^= k;
	      break;

	    case IORWF_k:
	      k |= w;
	      break;

	    case IORFW_k:
	      w |= k;
	      break;

	    case COMF_k:
	      k = ~k;
	      break;

	    case COMF_kw:
	      w = ~k;
	      break;


	    case CLRF_t:
	      t = 0;
	      break;

	    case  XORLW_ff:
	      w = ~w;
	      break;


	    case TOTAL_INSTRUCTIONS:
	      break;

	    }
	}

      if((r == 0x96) && (w == 0xe8) && (k==0xf0))
	{
	  printf("Found a solution!\n");

	  for(i = 0; i<PROGRAM_SIZE; i++)
	    {
	      printf("%s\n",opcodes[program[i]]);
	    }
	  printf("r+ = 0x%02x  w+ = 0x%02x\n",r,w);
	}

      if(( (count++)&0xffffff) == 0)
	{
	  for(i = 0; i<PROGRAM_SIZE; i++)
	    {
	      printf("0x%02x  ",program[i]);
	    }
	  printf("\n");
	}

      do
	{
	  if(program[current_address]++ > TOTAL_INSTRUCTIONS)
	    {
	      program[current_address] = NOP+1;
	      if(++current_address >= PROGRAM_SIZE)
		{
		  looping = 0;
		  done = 1;
		}
	      else
		looping = 1;
	    }
	  else
	    {
	      current_address = 0;
	      looping = 0;
	    }
	} while(looping);
 
    } while(!done);


}