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d52pass1.c

/*
 * D52 8052 Disassembler
 * Copyright (C) 1995-2007 by Jeffery L. Post
 * j_post <AT> pacbell <DOT> net
 *
 * d52pass1.c - Disassembly pass 1
 *
 * Version 3.4.1 - 2007/09/02
 *
 *    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 3 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 the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */

#include    <stdio.h>
#include    <stdlib.h>
#include    <ctype.h>
#include    <string.h>

#include    "d52.h"
#include    "common.h"
#include    "d52pass1.h"
#include    "d52pass2.h"
#include    "d52table.h"

//
// Pass one of disassembly
//
// Examine opcodes for internal references to other memory locations.
// If such references are found, flag the referenced location so that
// a label can be generated in the output file during pass two.
//

void pass1(void)
{
      int   i, l, pc, rel;
      byte  j, k, temp, mask;

      printf("\nPass 1 0000");

      for (i=offset; i<himark; )
      {
            l = i & 0xff;
            k = pgmmem[i];                                        // get stored opcode

            if (pgmflags[i] & PF_NOINIT)        // ignore un-initialized data
            {
                  pc = i;
                  i++;
                  i &= WORD_MASK;
            }
            else if (!(pgmflags[i] & (PF_ADRS | PF_WORD | PF_BYTE | PF_ASCII)))
            {                                                           // if code...
                  mask = (byte) PF_SPLIT;
                  j = opttbl[k];                            // get option byte

                  if ((j & OPT_MASK) == OPT_LREF)     // if ljmp, lcall, or mov dptr
                  {
                        pc = ((pgmmem[i + 1] & 0xff) << 8) | (pgmmem[i + 2] & 0xff);

                        if (pc >= offset && pc <= himark)
                              mask |= PF_NOINIT;

                        pgmflags[pc] = (pgmflags[pc] & ~mask) | PF_REF;
                                                                                          // flag reference
                  }

                  if (j & OPT_11)                     // if 11 bit adrs (ajmp & acall)
                  {
                        pc = ((i + 2) & 0xf800) | ((k & 0xe0) << 3) | (pgmmem[i+1] & 0xff);

                        if (pc >= offset && pc <= himark)
                              mask |= PF_NOINIT;

                        pgmflags[pc] = (pgmflags[pc] & ~mask) | PF_REF;
                                                                                          // flag reference
                  }

                  if (j & OPT_REL)                    // if relative reference
                  {
                        if (j & OPT_3)                            // if 3 byte relative address
                        {
                              temp = pgmmem[i + 2];   // get offset
                              rel = (temp > 0x7f) ? temp | 0xff00 : temp & 0xff;
                              pc = i + 3;
                        }
                        else                                            // else 2 byte relative address
                        {
                              temp = pgmmem[i+1];                       // get offset
                              rel = (temp > 0x7f) ? temp | 0xff00 : temp & 0xff;
                              pc = i + 2;
                        }

                        pc += rel;
                        pc &= WORD_MASK;

                        if (pc >= offset && pc <= himark)
                              mask |= PF_NOINIT;

                        pgmflags[pc] = (pgmflags[pc] & ~mask) | PF_REF;
                                                                                    // flag reference
                  }

                  pc = i;
                  i = i + (opttbl[k] & OPT_SIZE) + 1;       // update location pointer
                  i &= WORD_MASK;
            }
            else
            {
                  pc = i;
                  i++;
                  i &= WORD_MASK;
            }

            if (i < pc)                                     // oops! wrapped around...
                  break;

            if ((i & 0xff) < l)
                  printf("\rPass 1 %04x", i & 0xff00);
      }
      printf("\rPass 1 - Reference search complete");
}                                                                                   //  End of Pass 1

// end of d52pass1.c


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