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dz80pass1.c

/*
 * Z80 Disassembler
 * Copyright (C) 1990-2007 by Jeffery L. Post
 * j_post <AT> pacbell <DOT> net
 *
 * dz80pass1.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    "dz80.h"
#include    "common.h"
#include    "dz80pass1.h"
#include    "dz80pass2.h"
#include    "dz80table.h"
#include    "d80table.h"

//
//    Defined Constants
//
  /* none */

//
//    Global variables
//
  /* none */

//
// 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, mask;

      printf("Pass 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
                  i++;
            else if (!(pgmflags[i] & (PF_ADRS | PF_WORD | PF_BYTE | PF_ASCII)))
            {                                                           // if code...
                  mask = (byte) PF_SPLIT;

                  if (d8080)
                        j = opttbl80[k];              // get option byte
                  else
                        j = opttbl[k];                      // get option byte

                  if (j & OPT_DIR)                    // if absolute memory reference
                  {
                        pc = (pgmmem[i + 1] & 0xff) | ((pgmmem[i + 2] << 8) & 0xff00);

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

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

                  if (j & OPT_REL)                    // if relative memory reference
                  {
                        j = pgmmem[i + 1];            // get offset
                        rel = (j > 0x7f) ? j | 0xff00 : j & 0xff; // sign extend offset
                        pc = i + 2;
                        pc += rel;
                        pc &= WORD_MASK;

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

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

                  if (j & OPT_SPEC)                   // if special processing
                  {
                        j = pgmmem[i + 1];            // get second byte

                        switch (k)
                        {
                              case 0xed:
                                    if (edcode[j] & 2)
                                    {
                                          pc = (pgmmem[i + 2] & 0xff) |
                                                ((pgmmem[i + 3] << 8) & 0xff00);

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

                                          if (!(pgmflags[pc] & PF_NOLABEL))
                                                pgmflags[pc] = (pgmflags[pc] & ~mask) | PF_REF;
                                    }

                                    i += (edcode[j] & 3);
                                    break;

                              case 0xdd:
                              case 0xfd:
                                    if (j == 0x21 || j == 0x22 || j == 0x2a)
                                    {
                                          pc = (pgmmem[i + 2] & 0xff) |
                                                ((pgmmem[i + 3] << 8) & 0xff00);

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

                                          if (!(pgmflags[pc] & PF_NOLABEL))
                                                pgmflags[pc] = pgmflags[pc] | PF_REF;
                                    }

                                    i += (ddcode[j] & 3);
                                    break;
                        }
                  }

                  if (d8080)
                        i = i + (opttbl80[k] & OPT_SIZE) + 1;     // update location pointer
                  else
                        i = i + (opttbl[k] & OPT_SIZE) + 1;       // update location pointer
            }
            else
                  i++;

            if ((i & 0xff) < l)
                  printf("\rPass 1 %04x", i & 0xff00);
      }

      printf("\rPass 1 - Reference search complete");
}                                                                                   //  End of Pass 1

// end of dz80pass1.c


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