/*
*
*  mic1asm.java
*
*  mic1 microarchitecture simulator 
*  Copyright (C) 1999, Prentice-Hall, Inc. 
* 
*  This program is free software; you can redistribute it and/or modify 
*  it under the terms of the GNU General Public License as published by 
*  the Free Software Foundation; either version 2 of the License, or 
*  (at your option) any later version. 
* 
*  This program is distributed in the hope that it will be useful, but 
*  WITHOUT ANY WARRANTY; without even the implied warranty of 
*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General 
*  Public License for more details. 
* 
*  You should have received a copy of the GNU General Public License along with 
*  this program; if not, write to: 
* 
*    Free Software Foundation, Inc. 
*    59 Temple Place - Suite 330 
*    Boston, MA 02111-1307, USA. 
* 
*  A copy of the GPL is available online the GNU web site: 
* 
*    http://www.gnu.org/copyleft/gpl.html
* 
*/ 
// public class mic1asm

import java.net.* ;
import java.io.* ;
import java.util.* ;
import java_cup.runtime.* ;

/**
Reads a text file containing a Mic1 Micro-Assembly Language (MAL) 
program and produces a binary file containing Mic1 instructions, 
one 36-bit instruction per 40-bit word (the lower order 4 bits 
are not used).

@author 

Ray Ontko (<A HREF="mailto:rayo@ontko.com"><I>rayo@ontko.com</I></A>),
Ray Ontko & Co, 
Richmond, Indiana, US
*/

public class mic1asm implements Mic1Constants
{

public static void main( String[] args ) throws Exception
{
String infilename = null ;
String outfilename = null ;
BufferedInputStream in = null ;
DataOutputStream out = null ;

if ( args.length != 2 )
  {
  System.out.println( "usage: java mic1asm <infilename> <outfilename>" ) ;
  return;
  }

infilename = args[0] ; 
outfilename = args[1] ;

in = new BufferedInputStream( 
  new FileInputStream( new File( infilename ) ) ) ;
out = new DataOutputStream( 
  new FileOutputStream( new File( outfilename ) ) ) ;  

assemble( in , out ) ;

in.close() ;
out.close() ;
}

/**
assembles a Mic1 Micro-Assembly Language program which it reads 
from in, and writes to out.
*/
public static void assemble( BufferedInputStream in , DataOutputStream out )
{

int t ;
int c ;

StreamTokenizer st = new StreamTokenizer( in ) ;
st.resetSyntax() ;
st.slashSlashComments( true ) ;
st.whitespaceChars( 0 , ' ' ) ;
st.eolIsSignificant( true ) ;
st.wordChars( '.' , '.' ) ;
st.wordChars( '_' , '_' ) ;
st.wordChars( 'A' , 'Z' ) ;
st.wordChars( 'a' , 'z' ) ;
st.wordChars( '0' , '9' ) ;

Mic1Scanner.init( st ) ;
Mic1Parser p = new Mic1Parser() ;
try
  {
  // write magic number to output file
  out.write(mic1_magic1);
  out.write(mic1_magic2);
  out.write(mic1_magic3);
  out.write(mic1_magic4);

  boolean errorFound = false ;
  Symbol s = p.parse();

  String labels[] = new String[512] ;
  Mic1Parse mic1parse = (Mic1Parse)s.value ;

  // add the labels from the hash table to our labels array to
  // verify that no two labels are assigned to the same address
  Enumeration e = mic1parse.labels.keys() ; 
  while ( e.hasMoreElements() )
    {
    String l = (String)e.nextElement() ;
    Integer address = (Integer)mic1parse.labels.get(l) ;
    int a = address.intValue() ;
    // we should check to make sure labels[a] is null
    // else error: duplicate labels for this address
    if ( labels[a] == null )
      labels[a] = l ;
    else
      {
      System.out.println( "error: duplicate .label definitions " + 
        l + " and " + labels[a] + 
        " cannot share the same target address 0x" + Integer.toHexString(a) ) ;
      errorFound = true ;
      }
    }

  // System.out.println( "statementCount = " + mic1parse.statementCount ) ;
  // for( int i = 0 ; i < mic1parse.statementCount ; i++ )
  //   System.out.println( "  " + i + " " + mic1parse.statements[i].label ) ;

  // verify that all statement labels are unique
  for( int i = 0 ; i < mic1parse.statementCount - 1 ; i ++ )
    for( int j = i + 1 ; j < mic1parse.statementCount ; j ++ )
      if( mic1parse.statements[i].label.equals(
            mic1parse.statements[j].label ) )
        {
        System.out.println( "error: statements " + i + " and " + j +
          " cannot have the same label " + mic1parse.statements[i].label ) ;
        errorFound = true ;
        } 

  // give a goto to each statement which does not name its successor
  for( int i = 0 ; i < mic1parse.statementCount ; i ++ )
    {
    if( ! ( mic1parse.statements[i].isIf ||
            mic1parse.statements[i].isGoto ||
            mic1parse.statements[i].isMultiway ) )
      {
      if ( i + 1 < mic1parse.statementCount )
        {
        mic1parse.statements[i].gotoLabel = mic1parse.statements[i+1].label ;
        mic1parse.statements[i].isGoto = true ;
        }
      else
        {
        System.out.println( "error: final statement must have goto or if" ) ;
        errorFound = true ;
        }
      }
    }

  // verify that default statement exists
  if( mic1parse.defaultStatement == null )
    {
    System.out.println( "error: missing .default statement" ) ;
    errorFound = true ;
    }
  else
  // verify that default statment has goto
  if( ! ( mic1parse.defaultStatement.isIf ||
          mic1parse.defaultStatement.isGoto ||
          mic1parse.defaultStatement.isMultiway ) )
    {
    System.out.println( "error: default statement must have goto or if" ) ;
    errorFound = true ;
    }

  // make a pass to assign locations for all the isIf target pairs
  //
  // we should verify that all labels which participate in if statements
  // are always paired similarly (i.e., the "then" and "else" targets must 
  // always match anytime either appears in an if/else).
  int a = 0 ;
  for( int i = 0 ; i < mic1parse.statementCount ; i ++ )
    {
    if( mic1parse.statements[i].isIf )
      {
      boolean pairOk = true ;
      for( int j = i + 1 ; j < mic1parse.statementCount ; j ++ )
        {
        if( mic1parse.statements[j].isIf )
          {
          if( ( mic1parse.statements[i].gotoLabel.equals( 
                  mic1parse.statements[j].gotoLabel ) &&
                ! mic1parse.statements[i].elseLabel.equals(
                    mic1parse.statements[j].elseLabel ) ) ||
              ( mic1parse.statements[i].elseLabel.equals( 
                  mic1parse.statements[j].elseLabel ) &&
                ! mic1parse.statements[i].gotoLabel.equals(
                    mic1parse.statements[j].gotoLabel ) ) )
             {
             System.out.println( "error: if statements " + i + " and " + j + 
               " contain mismatched goto targets" ) ;
             errorFound = true ;
             pairOk = false ;
             }
          else if( mic1parse.statements[i].gotoLabel.equals(
                mic1parse.statements[j].elseLabel ) ||
              mic1parse.statements[i].elseLabel.equals(
                mic1parse.statements[j].gotoLabel ) )
             {
             System.out.println( "error: if statements " + i + " and " + j + 
               " cannot both use a label as a 'then' and 'else' goto target" ) ;
             errorFound = true ;
             pairOk = false ;
             }
          }
        // also, check against the default statement if it has an if
        if( mic1parse.defaultStatement.isIf )
          {
          if( ( mic1parse.statements[i].gotoLabel.equals( 
                  mic1parse.defaultStatement.gotoLabel ) &&
                ! mic1parse.statements[i].elseLabel.equals(
                    mic1parse.defaultStatement.elseLabel ) ) ||
              ( mic1parse.statements[i].elseLabel.equals( 
                  mic1parse.defaultStatement.elseLabel ) &&
                ! mic1parse.statements[i].gotoLabel.equals(
                    mic1parse.defaultStatement.gotoLabel ) ) )
             {
             System.out.println( "error: if statements " + i + 
               " and the .default statement" + 
               " contain mismatched goto targets" ) ;
             errorFound = true ;
             pairOk = false ;
             }
          else if( mic1parse.statements[i].gotoLabel.equals(
                mic1parse.defaultStatement.elseLabel ) ||
              mic1parse.statements[i].elseLabel.equals(
                mic1parse.defaultStatement.gotoLabel ) )
             {
             System.out.println( "error: if statements " + i + 
               " and the .default statement" + 
               " cannot both use a label as a 'then' and 'else' goto target" ) ;
             errorFound = true ;
             pairOk = false ;
             }
          }
        }
      if( pairOk )
        {
        // look for the elseLabel to see if it has an address
        Integer address = (Integer)mic1parse.labels.get( 
          mic1parse.statements[i].elseLabel ) ;
        // if the elseLabel does not have a value (in the labels hash table), 
        // find the next available pair of addresses (by looking in the array),
        // and give both the gotoLabel and the elseLabel values
        // by assigning them in the labels array and labels hash table.
        // if there are no free pairs, error
        if( address == null )
          {
          // find the first available address
          while( a < 256 )
            {
            if( labels[a] == null && labels[a+256] == null )
              break ;
            a ++ ;
            }
          if( a < 256 )
            {
            address = new Integer(a) ;
            mic1parse.add_label( mic1parse.statements[i].gotoLabel , 
                                 new Integer(a+256) ) ;
            labels[a+256] = mic1parse.statements[i].gotoLabel ;
            mic1parse.add_label( mic1parse.statements[i].elseLabel , 
                                 address ) ;
            labels[a] = mic1parse.statements[i].elseLabel ;
            }
          else
            {
            System.out.println( 
              "error: no room for if/else labels in statement " + i ) ;
            errorFound = true ;
            }
          }
        // update the NEXT_ADDRESS field for the statement.
        if( ! errorFound )
          mic1parse.statements[i].i.NEXT_ADDRESS = address.intValue() ;
        }
      }
    }
  if( mic1parse.defaultStatement.isIf )
    {
    // look for the elseLabel to see if it has an address
    Integer address = (Integer)mic1parse.labels.get( 
      mic1parse.defaultStatement.elseLabel ) ;
    // if the elseLabel does not have a value (in the labels hash table), 
    // find the next available pair of addresses (by looking in the array),
    // and give both the gotoLabel and the elseLabel values
    // by assigning them in the labels array and labels hash table.
    // if there are no free pairs, error
    if( address == null )
      {
      // find the first available address
      while( a < 256 )
        {
        if( labels[a] == null && labels[a+256] == null )
          break ;
        a ++ ;
        }
      if( a < 256 )
        {
        address = new Integer(a) ;
        mic1parse.add_label( mic1parse.defaultStatement.gotoLabel , 
                             new Integer(a+256) ) ;
        labels[a+256] = mic1parse.defaultStatement.gotoLabel ;
        mic1parse.add_label( mic1parse.defaultStatement.elseLabel , 
                             address ) ;
        labels[a] = mic1parse.defaultStatement.elseLabel ;
        }
      else
        {
        System.out.println( 
          "error: no room for if/else labels in .default statement " ) ;
        errorFound = true ;
        }
      }
    // update the NEXT_ADDRESS field for the statement.
    if( ! errorFound )
      mic1parse.defaultStatement.i.NEXT_ADDRESS = address.intValue() ;
    }

  a = 0 ;
  // make a pass to assign locations for all the isGoto targets
  for( int i = 0 ; i < mic1parse.statementCount ; i ++ )
    {
    if( mic1parse.statements[i].isGoto )
      {
      // check to see if the label already has an address. 
      Integer address = (Integer)mic1parse.labels.get( 
        mic1parse.statements[i].gotoLabel ) ;
      // If not, find the next available free address and assign
      // the value to the label in the array and the hash table.
      if( address == null )
        {
        for( ; labels[a] != null && a < 512 ; a ++ )
          // find the first available address
          ;
        if( a < 512 )
          {
          address = new Integer(a) ;
          mic1parse.add_label( mic1parse.statements[i].gotoLabel ,
                                address ) ;
          labels[a] = mic1parse.statements[i].gotoLabel ;
          }
        else
          {
          System.out.println( "error: no room for label in statement " + i ) ;
          errorFound = true ;
          }
        }
      // update the NEXT_ADDRESS field for the statement.
      if( ! errorFound )
        mic1parse.statements[i].i.NEXT_ADDRESS = address.intValue() ;
      }
    }
  // fix the label in the default statement if it is a goto
  if( mic1parse.defaultStatement.isGoto )
    {
    // check to see if the label already has an address. 
    Integer address = (Integer)mic1parse.labels.get( 
      mic1parse.defaultStatement.gotoLabel ) ;
    // If not, find the next available free address and assign
    // the value to the label in the array and the hash table.
    if( address == null )
      {
      for( ; labels[a] != null && a < 512 ; a ++ )
        // find the first available address
        ;
      if( a < 512 )
        {
        address = new Integer(a) ;
        mic1parse.add_label( mic1parse.defaultStatement.gotoLabel ,
                              address ) ;
        labels[a] = mic1parse.defaultStatement.gotoLabel ;
        }
      else
        {
        System.out.println( "error: no room for lable in default statement" ) ;
        errorFound = true ;
        }
      }
    // update the NEXT_ADDRESS field for the statement.
    if( ! errorFound )
      mic1parse.defaultStatement.i.NEXT_ADDRESS = address.intValue() ;
    }
 
  // by now, all labels which are used by statements are assigned to 
  // addresses. the labels are in the hash table with their assigned addresses.
  // we can use it to sequence through the statements and place them
  // into the control store.
  Mic1Instruction controlstore[] = new Mic1Instruction[512] ;
  if( ! errorFound )
    {
    for( int i = 0 ; i < mic1parse.statementCount ; i ++ )
      {
      String label = mic1parse.statements[i].label ;
      int address = ((Integer)mic1parse.labels.get( label )).intValue() ;
      if( controlstore[address] == null )
        controlstore[address] = mic1parse.statements[i].i ;
      else
        {
        // it might be better to check for uniqueness in a different pass
        System.out.println( "internal error: statement " + i + 
          "and some other statement are both mapped to address 0x" + 
          Integer.toHexString(address) ) ;
        errorFound = true ;
        }
      }
    // fill any empty spaces with the .default instruction
    for( int i = 0 ; i < 512 ; i ++ )
      if( controlstore[i] == null )
         controlstore[i] = mic1parse.defaultStatement.i ;
    }

  // write the results to an output file
  if( ! errorFound )
    {
    for( int i = 0 ; i < 512 ; i ++ )
      {
      // System.out.println( "0x" + Integer.toHexString(i) + ": " +
      //   controlstore[i].toString() ) ;
      controlstore[i].write(out) ;
      }
    }
  else
    {
    System.out.println( "errors found; no output file written" ) ;
    }

  }
catch (Exception e) 
  {
  System.out.println( "error: fata syntax error at line " + st.lineno() ) ;
  System.out.println( "exception: " + e );
  /* do cleanup here - - possibly rethrow e */
  } 

}

}