path: root/gas/as.c

/* as.c - GAS main program.
   Copyright (C) 1987, 90, 91, 92, 93, 94, 95, 96, 1997
   Free Software Foundation, Inc.

   This file is part of GAS, the GNU Assembler.

   GAS 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, or (at your option)
   any later version.

   GAS 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 GAS; see the file COPYING.  If not, write to the Free
   Software Foundation, 59 Temple Place - Suite 330, Boston, MA
   02111-1307, USA. */

/*
 * Main program for AS; a 32-bit assembler of GNU.
 * Understands command arguments.
 * Has a few routines that don't fit in other modules because they
 * are shared.
 *
 *
 *			bugs
 *
 * : initialisers
 *	Since no-one else says they will support them in future: I
 * don't support them now.
 *
 */

#include "ansidecl.h"

#define COMMON

#include "as.h"
#include "subsegs.h"
#include "output-file.h"
#include "sb.h"
#include "macro.h"
#ifndef HAVE_ITBL_CPU
#define itbl_parse(itbl_file) 1
#define itbl_init()
#endif

#ifdef HAVE_SBRK
#ifdef NEED_DECLARATION_SBRK
extern PTR sbrk ();
#endif
#endif

static void show_usage PARAMS ((FILE *));
static void parse_args PARAMS ((int *, char ***));
static void dump_statistics PARAMS ((void));
static void perform_an_assembly_pass PARAMS ((int argc, char **argv));
static int macro_expr PARAMS ((const char *, int, sb *, int *));

int listing;			/* true if a listing is wanted */

static char *listing_filename = NULL;	/* Name of listing file.  */

/* Type of debugging to generate.  */

enum debug_info_type debug_type = DEBUG_NONE;

/* Maximum level of macro nesting.  */

int max_macro_nest = 100;

char *myname;			/* argv[0] */
#ifdef BFD_ASSEMBLER
segT reg_section, expr_section;
segT text_section, data_section, bss_section;
#endif

int chunksize = 5000;

/* To monitor memory allocation more effectively, make this non-zero.
   Then the chunk sizes for gas and bfd will be reduced.  */
int debug_memory = 0;

/* We build a list of defsyms as we read the options, and then define
   them after we have initialized everything.  */

struct defsym_list
{
  struct defsym_list *next;
  char *name;
  valueT value;
};

static struct defsym_list *defsyms;

/* Keep a record of the itbl files we read in. */

struct itbl_file_list
{
  struct itbl_file_list *next;
  char *name;
};

static struct itbl_file_list *itbl_files;

void
print_version_id ()
{
  static int printed;
  if (printed)
    return;
  printed = 1;

  fprintf (stderr, "GNU assembler version %s (%s)", VERSION, TARGET_ALIAS);
#ifdef BFD_ASSEMBLER
  fprintf (stderr, ", using BFD version %s", BFD_VERSION);
#endif
  fprintf (stderr, "\n");
}

static void
show_usage (stream)
     FILE *stream;
{
  fprintf (stream, "Usage: %s [option...] [asmfile...]\n", myname);

  fprintf (stream, "\
Options:\n\
-a[sub-option...]	turn on listings\n\
  Sub-options [default hls]:\n\
  c	omit false conditionals\n\
  d	omit debugging directives\n\
  h	include high-level source\n\
  l	include assembly\n\
  n	omit forms processing\n\
  s	include symbols\n\
  =file set listing file name (must be last sub-option)\n");
  fprintf (stream, "\
-D			produce assembler debugging messages\n\
--defsym SYM=VAL	define symbol SYM to given value\n\
-f			skip whitespace and comment preprocessing\n\
--gstabs		generate stabs debugging information\n\
--help			show this message and exit\n\
-I DIR			add DIR to search list for .include directives\n\
-J			don't warn about signed overflow\n\
-K			warn when differences altered for long displacements\n\
-L			keep local symbols (starting with `L')\n");
  fprintf (stream, "\
-M,--mri		assemble in MRI compatibility mode\n\
--MD FILE		write dependency information in FILE (default none)\n\
-nocpp			ignored\n\
-o OBJFILE		name the object-file output OBJFILE (default a.out)\n\
-R			fold data section into text section\n\
--statistics		print various measured statistics from execution\n\
--version		print assembler version number and exit\n\
-W			suppress warnings\n\
--itbl INSTTBL		extend instruction set to include instructions\n\
			matching the specifications defined in file INSTTBL\n\
-w			ignored\n\
-X			ignored\n\
-Z			generate object file even after errors\n");

  md_show_usage (stream);

  fprintf (stream, "\nReport bugs to bug-gnu-utils@prep.ai.mit.edu\n");
}

#ifdef USE_EMULATIONS
#define EMULATION_ENVIRON "AS_EMULATION"

extern struct emulation mipsbelf, mipslelf, mipself;
extern struct emulation mipsbecoff, mipslecoff, mipsecoff;
extern struct emulation i386coff, i386elf;

static struct emulation *const emulations[] = { EMULATIONS };
static const int n_emulations = sizeof (emulations) / sizeof (emulations[0]);

static void select_emulation_mode PARAMS ((int, char **));

static void
select_emulation_mode (argc, argv)
     int argc;
     char **argv;
{
  int i;
  char *p, *em = 0;

  for (i = 1; i < argc; i++)
    if (!strncmp ("--em", argv[i], 4))
      break;

  if (i == argc)
    goto do_default;

  p = strchr (argv[i], '=');
  if (p)
    p++;
  else
    p = argv[i+1];

  if (!p || !*p)
    as_fatal ("missing emulation mode name");
  em = p;

 do_default:
  if (em == 0)
    em = getenv (EMULATION_ENVIRON);
  if (em == 0)
    em = DEFAULT_EMULATION;

  if (em)
    {
      for (i = 0; i < n_emulations; i++)
	if (!strcmp (emulations[i]->name, em))
	  break;
      if (i == n_emulations)
	as_fatal ("unrecognized emulation name `%s'", em);
      this_emulation = emulations[i];
    }
  else
    this_emulation = emulations[0];

  this_emulation->init ();
}

const char *
default_emul_bfd_name ()
{
  abort ();
  return NULL;
}

void
common_emul_init ()
{
  this_format = this_emulation->format;

  if (this_emulation->leading_underscore == 2)
    this_emulation->leading_underscore = this_format->dfl_leading_underscore;

  if (this_emulation->default_endian != 2)
    target_big_endian = this_emulation->default_endian;

  if (this_emulation->fake_label_name == 0)
    {
      if (this_emulation->leading_underscore)
	this_emulation->fake_label_name = "L0\001";
      else
	/* What other parameters should we test?  */
	this_emulation->fake_label_name = ".L0\001";
    }
}
#endif

/*
 * Since it is easy to do here we interpret the special arg "-"
 * to mean "use stdin" and we set that argv[] pointing to "".
 * After we have munged argv[], the only things left are source file
 * name(s) and ""(s) denoting stdin. These file names are used
 * (perhaps more than once) later.
 *
 * check for new machine-dep cmdline options in
 * md_parse_option definitions in config/tc-*.c
 */

static void
parse_args (pargc, pargv)
     int *pargc;
     char ***pargv;
{
  int old_argc, new_argc;
  char **old_argv, **new_argv;

  /* Starting the short option string with '-' is for programs that
     expect options and other ARGV-elements in any order and that care about
     the ordering of the two.  We describe each non-option ARGV-element
     as if it were the argument of an option with character code 1.  */

  char *shortopts;
  extern CONST char *md_shortopts;
  static const char std_shortopts[] =
    {
      '-', 'J',
#ifndef WORKING_DOT_WORD
      /* -K is not meaningful if .word is not being hacked.  */
      'K',
#endif
      'L', 'M', 'R', 'W', 'Z', 'f', 'a', ':', ':', 'D', 'I', ':', 'o', ':',
#ifndef VMS
      /* -v takes an argument on VMS, so we don't make it a generic
         option.  */
      'v',
#endif
      'w', 'X',
      /* New option for extending instruction set (see also --itbl below) */
      't', ':',
      '\0'
    };
  struct option *longopts;
  extern struct option md_longopts[];
  extern size_t md_longopts_size;
  static const struct option std_longopts[] = {
#define OPTION_HELP (OPTION_STD_BASE)
    {"help", no_argument, NULL, OPTION_HELP},
    {"mri", no_argument, NULL, 'M'},
#define OPTION_NOCPP (OPTION_STD_BASE + 1)
    {"nocpp", no_argument, NULL, OPTION_NOCPP},
#define OPTION_STATISTICS (OPTION_STD_BASE + 2)
    {"statistics", no_argument, NULL, OPTION_STATISTICS},
#define OPTION_VERSION (OPTION_STD_BASE + 3)
    {"version", no_argument, NULL, OPTION_VERSION},
#define OPTION_DUMPCONFIG (OPTION_STD_BASE + 4)
    {"dump-config", no_argument, NULL, OPTION_DUMPCONFIG},
#define OPTION_VERBOSE (OPTION_STD_BASE + 5)
    {"verbose", no_argument, NULL, OPTION_VERBOSE},
#define OPTION_EMULATION (OPTION_STD_BASE + 6)
    {"emulation", required_argument, NULL, OPTION_EMULATION},
#define OPTION_DEFSYM (OPTION_STD_BASE + 7)
    {"defsym", required_argument, NULL, OPTION_DEFSYM},
#define OPTION_INSTTBL (OPTION_STD_BASE + 8)
    /* New option for extending instruction set (see also -t above).
       The "-t file" or "--itbl file" option extends the basic set of
       valid instructions by reading "file", a text file containing a
       list of instruction formats.  The additional opcodes and their
       formats are added to the built-in set of instructions, and
       mnemonics for new registers may also be defined.  */
    {"itbl", required_argument, NULL, OPTION_INSTTBL},
#define OPTION_DEPFILE (OPTION_STD_BASE + 9)
    {"MD", required_argument, NULL, OPTION_DEPFILE},
#define OPTION_GSTABS (OPTION_STD_BASE + 10)
    {"gstabs", no_argument, NULL, OPTION_GSTABS}
  };

  /* Construct the option lists from the standard list and the
     target dependent list.  */
  shortopts = concat (std_shortopts, md_shortopts, (char *) NULL);
  longopts = (struct option *) xmalloc (sizeof (std_longopts) + md_longopts_size);
  memcpy (longopts, std_longopts, sizeof (std_longopts));
  memcpy ((char *) longopts + sizeof (std_longopts),
	  md_longopts, md_longopts_size);

  /* Make a local copy of the old argv.  */
  old_argc = *pargc;
  old_argv = *pargv;

  /* Initialize a new argv that contains no options.  */
  new_argv = (char **) xmalloc (sizeof (char *) * (old_argc + 1));
  new_argv[0] = old_argv[0];
  new_argc = 1;
  new_argv[new_argc] = NULL;

  while (1)
    {
      /* getopt_long_only is like getopt_long, but '-' as well as '--' can
	 indicate a long option.  */
      int longind;
      int optc = getopt_long_only (old_argc, old_argv, shortopts, longopts,
				   &longind);

      if (optc == -1)
	break;

      switch (optc)
	{
	default:
	  /* md_parse_option should return 1 if it recognizes optc,
	     0 if not.  */
	  if (md_parse_option (optc, optarg) != 0)
	    break;
	  /* `-v' isn't included in the general short_opts list, so check for
	     it explicity here before deciding we've gotten a bad argument.  */
	  if (optc == 'v')
	    {
#ifdef VMS
	      /* Telling getopt to treat -v's value as optional can result
		 in it picking up a following filename argument here.  The
		 VMS code in md_parse_option can return 0 in that case,
		 but it has no way of pushing the filename argument back.  */
	      if (optarg && *optarg)
		new_argv[new_argc++] = optarg,  new_argv[new_argc] = NULL;
	      else
#else
	      case 'v':
#endif
	      case OPTION_VERBOSE:
		print_version_id ();
	      break;
	    }
	  /*FALLTHRU*/

	case '?':
	  exit (EXIT_FAILURE);

	case 1:			/* File name.  */
	  if (!strcmp (optarg, "-"))
	    optarg = "";
	  new_argv[new_argc++] = optarg;
	  new_argv[new_argc] = NULL;
	  break;

	case OPTION_HELP:
	  show_usage (stdout);
	  exit (EXIT_SUCCESS);

	case OPTION_NOCPP:
	  break;

	case OPTION_STATISTICS:
	  flag_print_statistics = 1;
	  break;

	case OPTION_VERSION:
	  /* This output is intended to follow the GNU standards document.  */
	  printf ("GNU assembler %s\n", VERSION);
	  printf ("Copyright 1997 Free Software Foundation, Inc.\n");
	  printf ("\
This program is free software; you may redistribute it under the terms of\n\
the GNU General Public License.  This program has absolutely no warranty.\n");
	  printf ("This assembler was configured for a target of `%s'.\n",
		  TARGET_ALIAS);
	  exit (EXIT_SUCCESS);

	case OPTION_EMULATION:
#ifdef USE_EMULATIONS
	  if (strcmp (optarg, this_emulation->name))
	    as_fatal ("multiple emulation names specified");
#else
	  as_fatal ("emulations not handled in this configuration");
#endif
	  break;

	case OPTION_DUMPCONFIG:
	  fprintf (stderr, "alias = %s\n", TARGET_ALIAS);
	  fprintf (stderr, "canonical = %s\n", TARGET_CANONICAL);
	  fprintf (stderr, "cpu-type = %s\n", TARGET_CPU);
#ifdef TARGET_OBJ_FORMAT
	  fprintf (stderr, "format = %s\n", TARGET_OBJ_FORMAT);
#endif
#ifdef TARGET_FORMAT
	  fprintf (stderr, "bfd-target = %s\n", TARGET_FORMAT);
#endif
	  exit (EXIT_SUCCESS);

	case OPTION_DEFSYM:
	  {
	    char *s;
	    long i;
	    struct defsym_list *n;

	    for (s = optarg; *s != '\0' && *s != '='; s++)
	      ;
	    if (*s == '\0')
	      as_fatal ("bad defsym; format is --defsym name=value");
	    *s++ = '\0';
	    i = strtol (s, (char **) NULL, 0);
	    n = (struct defsym_list *) xmalloc (sizeof *n);
	    n->next = defsyms;
	    n->name = optarg;
	    n->value = i;
	    defsyms = n;
	  }
	  break;

	case OPTION_INSTTBL:
	case 't':
	  {
	    /* optarg is the name of the file containing the instruction 
	       formats, opcodes, register names, etc. */
	    struct itbl_file_list *n;

	    if (optarg == NULL)
	      {
		as_warn ( "No file name following -t option\n" );
		break;
	      }
	    
	    n = (struct itbl_file_list *) xmalloc (sizeof *n);
	    n->next = itbl_files;
	    n->name = optarg;
	    itbl_files = n;

	    /* Parse the file and add the new instructions to our internal
	       table.  If multiple instruction tables are specified, the 
	       information from this table gets appended onto the existing 
	       internal table. */
	    itbl_files->name = xstrdup (optarg);
	    if (itbl_parse (itbl_files->name) != 0)
	      {
		fprintf (stderr, "Failed to read instruction table %s\n", 
			 itbl_files->name);
		exit (EXIT_SUCCESS);
	      }
	  }
	  break;

	case OPTION_DEPFILE:
	  start_dependencies (optarg);
	  break;

	case OPTION_GSTABS:
	  debug_type = DEBUG_STABS;
	  break;

	case 'J':
	  flag_signed_overflow_ok = 1;
	  break;

#ifndef WORKING_DOT_WORD
	case 'K':
	  flag_warn_displacement = 1;
	  break;
#endif

	case 'L':
	  flag_keep_locals = 1;
	  break;

	case 'M':
	  flag_mri = 1;
#ifdef TC_M68K
	  flag_m68k_mri = 1;
#endif
	  break;

	case 'R':
	  flag_readonly_data_in_text = 1;
	  break;

	case 'W':
	  flag_no_warnings = 1;
	  break;

	case 'Z':
	  flag_always_generate_output = 1;
	  break;

	case 'a':
	  if (optarg)
	    {
	      while (*optarg)
		{
		  switch (*optarg)
		    {
		    case 'c':
		      listing |= LISTING_NOCOND;
		      break;
		    case 'd':
		      listing |= LISTING_NODEBUG;
		      break;
		    case 'h':
		      listing |= LISTING_HLL;
		      break;
		    case 'l':
		      listing |= LISTING_LISTING;
		      break;
		    case 'n':
		      listing |= LISTING_NOFORM;
		      break;
		    case 's':
		      listing |= LISTING_SYMBOLS;
		      break;
		    case '=':
		      listing_filename = xstrdup (optarg + 1);
		      optarg += strlen (listing_filename);
		      break;
		    default:
		      as_fatal ("invalid listing option `%c'", *optarg);
		      break;
		    }
		  optarg++;
		}
	    }
	  if (!listing)
	    listing = LISTING_DEFAULT;
	  break;

	case 'D':
	  /* DEBUG is implemented: it debugs different */
	  /* things from other people's assemblers. */
	  flag_debug = 1;
	  break;

	case 'f':
	  flag_no_comments = 1;
	  break;

	case 'I':
	  {			/* Include file directory */
	    char *temp = xstrdup (optarg);
	    add_include_dir (temp);
	    break;
	  }

	case 'o':
	  out_file_name = xstrdup (optarg);
	  break;

	case 'w':
	  break;

	case 'X':
	  /* -X means treat warnings as errors */
	  break;
	}
    }

  free (shortopts);
  free (longopts);

  *pargc = new_argc;
  *pargv = new_argv;
}

static long start_time;

int 
main (argc, argv)
     int argc;
     char **argv;
{
  int macro_alternate;
  int macro_strip_at;
  int keep_it;

  start_time = get_run_time ();


  if (debug_memory)
    {
#ifdef BFD_ASSEMBLER
      extern long _bfd_chunksize;
      _bfd_chunksize = 64;
#endif
      chunksize = 64;
    }

#ifdef HOST_SPECIAL_INIT
  HOST_SPECIAL_INIT (argc, argv);
#endif

  myname = argv[0];
  xmalloc_set_program_name (myname);

  START_PROGRESS (myname, 0);

#ifndef OBJ_DEFAULT_OUTPUT_FILE_NAME
#define OBJ_DEFAULT_OUTPUT_FILE_NAME "a.out"
#endif

  out_file_name = OBJ_DEFAULT_OUTPUT_FILE_NAME;

  hex_init ();
#ifdef BFD_ASSEMBLER
  bfd_init ();
  bfd_set_error_program_name (myname);
#endif

#ifdef USE_EMULATIONS
  select_emulation_mode (argc, argv);
#endif

  PROGRESS (1);
  symbol_begin ();
  frag_init ();
  subsegs_begin ();
  parse_args (&argc, &argv); 
  read_begin ();
  input_scrub_begin ();
  expr_begin ();

  if (flag_print_statistics)
    xatexit (dump_statistics);

  macro_alternate = 0;
  macro_strip_at = 0;
#ifdef TC_I960
  macro_strip_at = flag_mri;
#endif
#ifdef TC_A29K
  /* For compatibility with the AMD 29K family macro assembler
     specification.  */
  macro_alternate = 1;
  macro_strip_at = 1;
#endif

  macro_init (macro_alternate, flag_mri, macro_strip_at, macro_expr);

  PROGRESS (1);

#ifdef BFD_ASSEMBLER
  output_file_create (out_file_name);
  assert (stdoutput != 0);
#endif

#ifdef tc_init_after_args
  tc_init_after_args ();
#endif

  itbl_init ();

  /* Now that we have fully initialized, and have created the output
     file, define any symbols requested by --defsym command line
     arguments.  */
  while (defsyms != NULL)
    {
      symbolS *sym;
      struct defsym_list *next;

      sym = symbol_new (defsyms->name, absolute_section, defsyms->value,
			&zero_address_frag);
      symbol_table_insert (sym);
      next = defsyms->next;
      free (defsyms);
      defsyms = next;
    }

  PROGRESS (1);

  perform_an_assembly_pass (argc, argv);	/* Assemble it. */

  cond_finish_check (-1);

#ifdef md_end
  md_end ();
#endif

  if (seen_at_least_1_file ()
      && (flag_always_generate_output || had_errors () == 0))
    keep_it = 1;
  else
    keep_it = 0;

  if (keep_it)
    write_object_file ();

#ifndef NO_LISTING
  listing_print (listing_filename);
#endif

#ifndef OBJ_VMS /* does its own file handling */
#ifndef BFD_ASSEMBLER
  if (keep_it)
#endif
    output_file_close (out_file_name);
#endif

  if (had_errors () > 0 && ! flag_always_generate_output)
    keep_it = 0;

  if (!keep_it)
    unlink (out_file_name);

  input_scrub_end ();

  END_PROGRESS (myname);

  /* Use xexit instead of return, because under VMS environments they
     may not place the same interpretation on the value given.  */
  if (had_errors () > 0)
    xexit (EXIT_FAILURE);

  /* Only generate dependency file if assembler was successful.  */
  print_dependencies ();

  xexit (EXIT_SUCCESS);
}

static void
dump_statistics ()
{
  extern char **environ;
#ifdef HAVE_SBRK
  char *lim = (char *) sbrk (0);
#endif
  long run_time = get_run_time () - start_time;

  fprintf (stderr, "%s: total time in assembly: %ld.%06ld\n",
	   myname, run_time / 1000000, run_time % 1000000);
#ifdef HAVE_SBRK
  fprintf (stderr, "%s: data size %ld\n",
	   myname, (long) (lim - (char *) &environ));
#endif

  subsegs_print_statistics (stderr);
  write_print_statistics (stderr);
  symbol_print_statistics (stderr);
  read_print_statistics (stderr);

#ifdef tc_print_statistics
  tc_print_statistics (stderr);
#endif
#ifdef obj_print_statistics
  obj_print_statistics (stderr);
#endif
}


/*			perform_an_assembly_pass()
 *
 * Here to attempt 1 pass over each input file.
 * We scan argv[*] looking for filenames or exactly "" which is
 * shorthand for stdin. Any argv that is NULL is not a file-name.
 * We set need_pass_2 TRUE if, after this, we still have unresolved
 * expressions of the form (unknown value)+-(unknown value).
 *
 * Note the un*x semantics: there is only 1 logical input file, but it
 * may be a catenation of many 'physical' input files.
 */
static void 
perform_an_assembly_pass (argc, argv)
     int argc;
     char **argv;
{
  int saw_a_file = 0;
#ifdef BFD_ASSEMBLER
  flagword applicable;
#endif

  need_pass_2 = 0;

#ifndef BFD_ASSEMBLER
#ifdef MANY_SEGMENTS
  {
    unsigned int i;
    for (i = SEG_E0; i < SEG_UNKNOWN; i++)
      segment_info[i].fix_root = 0;
  }
  /* Create the three fixed ones */
  {
    segT seg;

#ifdef TE_APOLLO
    seg = subseg_new (".wtext", 0);
#else
    seg = subseg_new (".text", 0);
#endif
    assert (seg == SEG_E0);
    seg = subseg_new (".data", 0);
    assert (seg == SEG_E1);
    seg = subseg_new (".bss", 0);
    assert (seg == SEG_E2);
#ifdef TE_APOLLO
    create_target_segments ();
#endif
  }

#else /* not MANY_SEGMENTS */
  text_fix_root = NULL;
  data_fix_root = NULL;
  bss_fix_root = NULL;
#endif /* not MANY_SEGMENTS */
#else /* BFD_ASSEMBLER */
  /* Create the standard sections, and those the assembler uses
     internally.  */
  text_section = subseg_new (".text", 0);
  data_section = subseg_new (".data", 0);
  bss_section = subseg_new (".bss", 0);
  /* @@ FIXME -- we're setting the RELOC flag so that sections are assumed
     to have relocs, otherwise we don't find out in time. */
  applicable = bfd_applicable_section_flags (stdoutput);
  bfd_set_section_flags (stdoutput, text_section,
			 applicable & (SEC_ALLOC | SEC_LOAD | SEC_RELOC
				       | SEC_CODE | SEC_READONLY));
  /* @@ FIXME -- SEC_CODE seems to mean code only, rather than code possibly.*/
  bfd_set_section_flags (stdoutput, data_section,
			 applicable & (SEC_ALLOC | SEC_LOAD | SEC_RELOC));
  bfd_set_section_flags (stdoutput, bss_section, applicable & SEC_ALLOC);
  seg_info (bss_section)->bss = 1;
  subseg_new (BFD_ABS_SECTION_NAME, 0);
  subseg_new (BFD_UND_SECTION_NAME, 0);
  reg_section = subseg_new ("*GAS `reg' section*", 0);
  expr_section = subseg_new ("*GAS `expr' section*", 0);

#endif /* BFD_ASSEMBLER */

  subseg_set (text_section, 0);

  /* This may add symbol table entries, which requires having an open BFD,
     and sections already created, in BFD_ASSEMBLER mode.  */
  md_begin ();

#ifdef obj_begin
  obj_begin ();
#endif

  argv++;			/* skip argv[0] */
  argc--;			/* skip argv[0] */
  while (argc--)
    {
      if (*argv)
	{			/* Is it a file-name argument? */
	  PROGRESS (1);
	  saw_a_file++;
	  /* argv->"" if stdin desired, else->filename */
	  read_a_source_file (*argv);
	}
      argv++;			/* completed that argv */
    }
  if (!saw_a_file)
    read_a_source_file ("");
}				/* perform_an_assembly_pass() */

/* The interface between the macro code and gas expression handling.  */

static int
macro_expr (emsg, idx, in, val)
     const char *emsg;
     int idx;
     sb *in;
     int *val;
{
  char *hold;
  expressionS ex;

  sb_terminate (in);

  hold = input_line_pointer;
  input_line_pointer = in->ptr + idx;
  expression (&ex);
  idx = input_line_pointer - in->ptr;
  input_line_pointer = hold;

  if (ex.X_op != O_constant)
    as_bad ("%s", emsg);

  *val = (int) ex.X_add_number;

  return idx;
}

/* end of as.c */