/******************************************************************
 *
 * Copyright (c) 2003 Benjamin `Quisar' Lerman.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions  
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *   
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
 * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 ******************************************************************/

#define PUSH             0
#define DUP              1
#define SWAP             2
#define DISCARD          3

#define ADD              4
#define SUB              5
#define MUL              6
#define INTDIV           7
#define MODULO           8

#define CALL             9
#define JUMP            10
#define JUMPZ           11
#define JUMPNEG         12
#define ENDSUB          13
#define END             14

#define STORE           15
#define RETR            16

#define OUTCHAR         17
#define OUTNUM          18
#define INCHAR          19
#define INNUM           20

#define LABEL		21

int counteur;
int stack;
int mem;
int parse_error;
int com_erreur;

main()
{
  int size_used;

  parse_error = "Parse Error.\n";
  com_erreur = "Unknown Command.\n";
  counteur = *0;
  size_used = get_code(counteur);
  *0 += size_used;
  stack = *0;
  mem = (*0 + 1);
  resolve_label(counteur,size_used);
  execute_code(counteur);
}

execute_code(pc)
{
  int r;
  int s;
  int t;
  while(1)
  {
    if(*pc == PUSH)
    {
      *stack = *(pc + 1);
      stack += 2;
    }
    else if(*pc == DUP)
    {
      *stack = *(stack -2);
      stack += 2;
    }
    else if(*pc == SWAP)
    {
      t = *(stack - 2);
      *(stack - 2) = *(stack - 4);
      *(stack - 4) = t;
    }
    else if(*pc == DISCARD)
    {
      stack -= 2;
    }
    else if(*pc == ADD)
    {
      stack -= 2;
      *(stack - 2) = *(stack - 2) + *(stack);
    }
    else if(*pc == SUB)
    {
      stack -= 2;
      *(stack - 2) = *(stack - 2) - *(stack);
    } 
    else if(*pc == MUL)
    {
      stack -= 2;
      *(stack - 2) = *(stack - 2) * *(stack);
    } 
    else if(*pc == INTDIV)
    {
      stack -= 2;
      *(stack - 2) = *(stack - 2) / *(stack);
    } 
    else if(*pc == MODULO)
    {
      stack -= 2;
      *(stack - 2) = *(stack - 2) % *(stack);
    } 
    else if(*pc == CALL)
    {
      execute_code(*(pc+1));
    } 
    else if(*pc == JUMP)
    {
      pc = *(pc+1) -2;
    } 
    else if(*pc == JUMPZ)
    {
      stack -= 2;
      if(*stack == 0)
	pc = *(pc+1) -2;
    } 
    else if(*pc == JUMPNEG)
    {
      stack -= 2;
      if(*stack < 0)
	pc = *(pc+1) -2;
    } 
    else if(*pc == ENDSUB)
    {
      return 0;
    } 
    else if(*pc == END)
    {
      exit(0);
    } 
    else if(*pc == STORE)
    {
      stack -= 2;
      t = *stack;
      stack -= 2;
      r = *stack;
      if(r < 0)
      {
	s = mem + 2 - 4 * r;
      }
      else
      {
	s= mem + 4 * r;
      }
      *s = t;
    } 
    else if(*pc == RETR)
    {
      stack -= 2;
      r = *stack;
      if(r < 0)
      {
	s = mem + 2 - 4 * r;
      }
      else
      {
	s = mem + 4 * r;
      }
      *stack = *s;
      stack += 2;
    } 
    else if(*pc == OUTCHAR)
    {
      stack -= 2;
      outchar *stack;
    } 
    else if(*pc == OUTNUM)
    {
      stack -= 2;
      outint *stack;
    } 
    else if(*pc == INCHAR)
    {
    } 
    else if(*pc == INNUM)
    {
    } 
    else if(*pc == LABEL)
    {
    } 
    pc+=2;
  }
  return 0;
}

printint(i)
{
  outint i;
  outchar '\n';
  return 0;
}

get_code(place)
{
  int c;

  c = get_next_space();
  if(c == -1)
    return 0;
  if(c == ' ')
  {
    if(!stackman(place))
      return 2+get_code(place+2);
    return 0;
  }
  if(c == '\t')
  {
    c = get_next_space();
    if(c == -1)
    {
      print(parse_error);
      return 0;
    }
    if(c == ' ')
    {
      if(!ariman(place))
	return 2+get_code(place+2);
      {
	print(parse_error);
        return 0;
      }
    }
    if(c == '\t')
    {
      if(!heapaccman(place))
	return 2+get_code(place+2);
      {
	print(parse_error);
        return 0;
      }
    }
    if(c == '\n')
    {
      if(!ioman(place))
	return 2+get_code(place+2);
      print(parse_error);
      return 0;
    }
    /* CAN'T HAPPEN */
    return -1;
  }
  if(c == '\n')
  {
    if(!flowman(place))
      return 2+get_code(place+2);
    print(parse_error);
    return 0;
  }
  /* CAN'T HAPPEN */
  return 0;
}

ariman(place)
{
  int c;
  int d;
  c = get_next_space();
  d = get_next_space();
  if(c == ' ')
  {
    if(d == ' ')
    {
      *place = ADD;
      return 0;
    }
    if(d == '\t')
    {
      *place = SUB;
      return 0;
    }
    if(d == '\n')
    {
      *place = MUL;
      return 0;
    }
    return -1;
  }
  if(c == '\t')
  {
    if(d == ' ')
    {
      *place = INTDIV;
      return 0;
    }
    if(d == '\t')
    {
      *place = MODULO;
      return 0;
    }
  }
  return -1;
}

heapaccman(place)
{
  int c;
  c = get_next_space();
  if(c == ' ')
  {
    *place = STORE;
    return 0;
  }
  if(c == '\t')
  {
    *place = RETR;
    return 0;
  }
  return -1;
}

ioman(place)
{
  int c;
  int d;
  c = get_next_space();
  d = get_next_space();
  if(c == ' ')
  {
    if(d == ' ')
    {
      *place = OUTCHAR;
      return 0;
    }
    if(d == '\t')
    {
      *place = OUTNUM;
      return 0;
    }
    return -1;
  }
  if(c == '\t')
  {
    if(d == ' ')
    {
      *place = INCHAR;
      return 0;
    }
    if(d == '\t')
    {
      *place = INNUM;
      return 0;
    }
  }
  return -1;
}

flowman(place)
{
  int c;
  int d;
  c = get_next_space();
  d = get_next_space();

  if(c == ' ')
  {
    if(d == ' ')
    {
      *place = LABEL;
      place++;
      *place = readlabel();
      if(*place < 1)
	return -1;
      return 0;
    }
    if(d == '\t')
    {
      *place = CALL;
      place++;
      *place = readlabel();
      if(*place < 1)
	return -1;
      return 0;
    }
    if(d == '\n')
    {
      *place = JUMP;
      place++;
      *place = readlabel();
      if(*place < 1)
	return -1;
      return 0;
    }
    return -1;
  }
  if(c == '\t')
  {
    if(d == ' ')
    {
      *place = JUMPZ;
      place++;
      *place = readlabel();
      if(*place < 1)
	return -1;
      return 0;
    }
    if(d == '\t')
    {
      *place = JUMPNEG;
      place++;
      *place = readlabel();
      if(*place < 1)
	return -1;
      return 0;
    }
    if(d == '\n')
    {
      *place = ENDSUB;
      return 0;
    }
    return -1;
  }
  if((c == '\n') && (d == '\n'))
  {
    *place = END;
    return 0;
  }
  return -1;
}

stackman(place)
{
  int c;

  c = get_next_space();
  if(c == -1)
    return -1;
  if(c == ' ')
  {
    *place = PUSH;
    place++;
    *place = readnum();
    return 0;
  }
  if(c == '\n')
  {
    c = get_next_space();
    if(c == -1)
      return -1;
    if(c == ' ')
    {
      *place = DUP;
    }
    else if(c == '\t')
    {
      *place = SWAP;
    }
    else *place = DISCARD;
    return 0;
    
  }
  if(c == '\t')
    return -1;
  /* CAN'T HAPPEN */
  return -1;
}

get_next_space()
{
  int c;
  do
  {
    getchar c;
  } while((c!=-1) && (c!='\n') && (c!=' ') && (c!='\t'));
  return c;
}

readlabel()
{
  int c;
  c = get_next_space();
  if(c == -1)
    return -1;
  if(c == '\n')
    return 1;
  if(c == '\t')
    return 2*readlabel() + 1;
  return 2*readlabel();
}

readnum()
{
  int c;
  c = get_next_space();
  if(c == -1)
    return -1;
  if(c == '\n')
    return 0;
  if(c == '\t')
    return -1 * readnum2(0);
  return readnum2(0);
}

readnum2(i)
{
  int c;
  int d;
  c = get_next_space();
  if(c == -1)
    return i;
  if(c == '\n')
    return i;
  if(c == ' ')
    return readnum2(2*i);
  else
    return readnum2(2*i+1);
}

print(c)
{
  while(*c)
  {
    outchar *c;
    c++;
  }
}

resolve_label(counter,size)
{
  int i;
  int j;
  int k;
  int l;

  for(i=counter; i<counter+size; i+=2)
  {
    if(*i == LABEL)
    {
      k = i + 1;
      for(j=counter; j<counter+size; j+=2)
      {
	if((*j == CALL) || (*j == JUMP) || (*j == JUMPZ) || (*j == JUMPNEG))
	{
	  l = j + 1;
	  if(*k == *l)
	  {
	    *l = i;
	  }
	}
      }
    }
  }
}