ieee.c

早期freebsd实现

/* BFD back-end for ieee-695 objects.
   Copyright 1990, 1991, 1992 Free Software Foundation, Inc.
   Written by Steve Chamberlain of Cygnus Support.

This file is part of BFD, the Binary File Descriptor library.

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 the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

#define KEEPMINUSPCININST 1

/* IEEE 695 format is a stream of records, which we parse using a simple one-
   token (which is one byte in this lexicon) lookahead recursive decent
   parser.  */

#include "bfd.h"
#include "sysdep.h"
#include "libbfd.h"
#include "ieee.h"
#include "libieee.h"


#include "obstack.h"
#define obstack_chunk_alloc bfd_xmalloc
#define obstack_chunk_free free

/* Functions for writing to ieee files in the strange way that the
   standard requires. */

static void
DEFUN(ieee_write_byte,(abfd, byte),
      bfd *abfd AND
      bfd_byte byte)
{
  bfd_write((PTR)&byte, 1, 1, abfd);
}


static void
DEFUN(ieee_write_twobyte,(abfd, twobyte),
      bfd *abfd AND
      int twobyte)
{
  bfd_byte b[2];
  b[1] = twobyte & 0xff;
  b[0] = twobyte >> 8;
  bfd_write((PTR)&b[0], 1, 2, abfd);
}



static void
DEFUN(ieee_write_2bytes,(abfd, bytes),
      bfd *abfd AND
      int bytes)
{
  bfd_byte buffer[2];
  buffer[0] = bytes >> 8;
  buffer[1] = bytes & 0xff;

  bfd_write((PTR)buffer, 1, 2, abfd);
}

static void
DEFUN(ieee_write_int,(abfd, value),
      bfd *abfd AND
      bfd_vma value)
{
  if (((unsigned)value) <= 127) {
    ieee_write_byte(abfd, value);
  }
  else {
    unsigned int length;
    /* How many significant bytes ? */
    /* FIXME FOR LONGER INTS */
    if (value & 0xff000000) {
      length = 4;
    }
    else if (value & 0x00ff0000) {
      length  = 3;
    }
    else if (value & 0x0000ff00) {
      length = 2;
    }
    else length = 1;

    ieee_write_byte(abfd, (int)ieee_number_repeat_start_enum + length);
    switch (length) {
    case 4:
      ieee_write_byte(abfd, value >> 24);
    case 3:
      ieee_write_byte(abfd, value >> 16);
    case 2:
      ieee_write_byte(abfd, value >> 8);
    case 1:
      ieee_write_byte(abfd, value);
    }
  }
}

static void
DEFUN(ieee_write_id,(abfd, id),
      bfd *abfd AND
      CONST char *id)
{
  size_t length = strlen(id);
  if (length >= 0 && length <= 127) {
    ieee_write_byte(abfd, length);
  }
  else if (length < 255) {
    ieee_write_byte(abfd, ieee_extension_length_1_enum);
    ieee_write_byte(abfd, length);
  }
  else if (length < 65535) {
    ieee_write_byte(abfd, ieee_extension_length_2_enum);
    ieee_write_byte(abfd, length >> 8);
    ieee_write_byte(abfd, length & 0xff);  
  }
  else {
    BFD_FAIL();
  }
  bfd_write((PTR)id, 1, length, abfd);
}
/***************************************************************************
Functions for reading from ieee files in the strange way that the
standard requires:
*/


#define this_byte(ieee) *((ieee)->input_p)
#define next_byte(ieee) ((ieee)->input_p++)
#define this_byte_and_next(ieee) (*((ieee)->input_p++))


static unsigned short 
DEFUN(read_2bytes,(ieee),
   common_header_type *ieee)
{
  unsigned  char c1 = this_byte_and_next(ieee);
  unsigned  char c2 = this_byte_and_next(ieee);
  return (c1<<8 ) | c2;

}

static void
DEFUN(bfd_get_string,(ieee, string, length),
    common_header_type *ieee AND
      char *string AND
      size_t length)
{
  size_t i;
  for (i= 0; i < length; i++) {
    string[i] = this_byte_and_next(ieee);
  }
}

static char *
DEFUN(read_id,(ieee),
  common_header_type *ieee)
{
  size_t length;
  char *string;
  length = this_byte_and_next(ieee);
  if (length >= 0x00 && length <= 0x7f) {
    /* Simple string of length 0 to 127 */
  }
  else if (length == 0xde) {
    /* Length is next byte, allowing 0..255 */
    length = this_byte_and_next(ieee);
  }
  else if (length == 0xdf) {
    /* Length is next two bytes, allowing 0..65535 */
    length = this_byte_and_next(ieee) ;
    length = (length * 256) + this_byte_and_next(ieee);
  }
  /* Buy memory and read string */
  string = bfd_alloc(ieee->abfd, length+1);
  bfd_get_string(ieee, string, length);
  string[length] = 0;
  return string;
}

static void
DEFUN(ieee_write_expression,(abfd, value, symbol, pcrel, index),
      bfd*abfd AND
      bfd_vma value AND
      asymbol *symbol AND
      boolean pcrel AND
    unsigned int index)
{
  unsigned int term_count = 0;

  if (value != 0) 
  {
    ieee_write_int(abfd, value);
    term_count++;
  }
  
     

  if (symbol->section == &bfd_com_section
      || symbol->section == &bfd_und_section) 
  {
    /* Def of a common symbol */
    ieee_write_byte(abfd, ieee_variable_X_enum);
    ieee_write_int(abfd, symbol->value);
    term_count++;
  }
  else  if (symbol->section != &bfd_abs_section) 
  {
    /* Ref to defined symbol - */
  
    ieee_write_byte(abfd, ieee_variable_R_enum);
    ieee_write_byte(abfd, symbol->section->index + IEEE_SECTION_NUMBER_BASE);
    term_count++;
    if (symbol->flags & BSF_GLOBAL) 
    {
      ieee_write_byte(abfd, ieee_variable_I_enum);
      ieee_write_int(abfd, symbol->value);
      term_count++;
    }
    else if (symbol->flags & ( BSF_LOCAL | BSF_SECTION_SYM))
    {
      /* This is a reference to a defined local symbol, 
	 We can easily do a local as a section+offset */
      ieee_write_byte(abfd, ieee_variable_R_enum); /* or L */
      ieee_write_byte(abfd, symbol->section->index +
		      IEEE_SECTION_NUMBER_BASE);
      ieee_write_int(abfd, symbol->value);
      term_count++;

    }
    else   {
	BFD_FAIL();
      }

  }

 
  
  if(pcrel) {
      /* subtract the pc from here by asking for PC of this section*/
      ieee_write_byte(abfd, ieee_variable_P_enum);
      ieee_write_byte(abfd, index  +IEEE_SECTION_NUMBER_BASE);
      ieee_write_byte(abfd, ieee_function_minus_enum);
    }

  if (term_count == 1) 
  {
    ieee_write_byte(abfd,0);
  }
  else {    
      while (term_count > 1) {
	  ieee_write_byte(abfd, ieee_function_plus_enum);
	  term_count--;
	}

    }

}








/*****************************************************************************/

/*
writes any integer into the buffer supplied and always takes 5 bytes
*/
static void
DEFUN(ieee_write_int5,(buffer, value),
      bfd_byte*buffer AND
      bfd_vma value )
{
  buffer[0] = (bfd_byte)ieee_number_repeat_4_enum;
  buffer[1] = (value >> 24 ) & 0xff;
  buffer[2] = (value >> 16 ) & 0xff;
  buffer[3] = (value >> 8 ) & 0xff;
  buffer[4] = (value >> 0 ) & 0xff;
}
static void
DEFUN(ieee_write_int5_out, (abfd, value),
      bfd *abfd AND
      bfd_vma value)
{
  bfd_byte b[5];
  ieee_write_int5(b, value);
  bfd_write((PTR)b,1,5,abfd);
}


static boolean 
DEFUN(parse_int,(ieee, value_ptr),
      common_header_type  *ieee AND
      bfd_vma *value_ptr)
{
  int value = this_byte(ieee);
  int result;
  if (value >= 0 && value <= 127) {
    *value_ptr = value;
    next_byte(ieee);
    return true;
  } 
  else if (value >= 0x80 && value <= 0x88) {
    unsigned int count = value & 0xf;
    result = 0;
    next_byte(ieee);
    while (count) {
      result =(result << 8) | this_byte_and_next(ieee);
      count--;
    }
    *value_ptr = result;
    return true;
  } 
  return false;
}
static int
DEFUN(parse_i,(ieee, ok),
   common_header_type *ieee AND
      boolean *ok)
{
  bfd_vma x;
  *ok = parse_int(ieee, &x);
  return x;
}

static bfd_vma 
DEFUN(must_parse_int,(ieee),
     common_header_type *ieee)
{
  bfd_vma result;
  BFD_ASSERT(parse_int(ieee, &result) == true);
  return result;
}

typedef struct 
{
  bfd_vma value;
  asection *section;
  ieee_symbol_index_type symbol;
} ieee_value_type;


static 
reloc_howto_type abs32_howto 
 = HOWTO(1,0,2,32,false,0,false,true,0,"abs32",true,0xffffffff, 0xffffffff,false);
static
reloc_howto_type abs16_howto 
 = HOWTO(1,0,1,16,false,0,false,true,0,"abs16",true,0x0000ffff, 0x0000ffff,false);

static
reloc_howto_type abs8_howto 
 = HOWTO(1,0,0,8,false,0,false,true,0,"abs8",true,0x000000ff, 0x000000ff,false);

static 
reloc_howto_type rel32_howto 
 = HOWTO(1,0,2,32,true,0,false,true,0,"rel32",true,0xffffffff,
	 0xffffffff,false);

static
reloc_howto_type rel16_howto 
 = HOWTO(1,0,1,16,true,0,false,true,0,"rel16",true,0x0000ffff, 0x0000ffff,false);

static
reloc_howto_type rel8_howto 
 = HOWTO(1,0,0,8,true,0,false,true,0,"rel8",true,0x000000ff, 0x000000ff,false);


static ieee_symbol_index_type NOSYMBOL = {  0, 0};


static void
DEFUN(parse_expression,(ieee, value, symbol, pcrel, extra, section),
      ieee_data_type *ieee AND
      bfd_vma *value AND
      ieee_symbol_index_type *symbol AND
      boolean *pcrel AND
      unsigned int *extra AND
      asection **section)

{
#define POS sp[1]
#define TOS sp[0]
#define NOS sp[-1]
#define INC sp++;
#define DEC sp--;

  
  boolean loop = true;
  ieee_value_type stack[10];

  /* The stack pointer always points to the next unused location */
#define PUSH(x,y,z) TOS.symbol=x;TOS.section=y;TOS.value=z;INC;
#define POP(x,y,z) DEC;x=TOS.symbol;y=TOS.section;z=TOS.value;
  ieee_value_type *sp = stack;

  while (loop) {
    switch (this_byte(&(ieee->h))) 
	{
	case ieee_variable_P_enum:
	  /* P variable, current program counter for section n */
	    {
	      int section_n ;
	      next_byte(&(ieee->h));
	      *pcrel = true;
	      section_n  = must_parse_int(&(ieee->h));
	      PUSH(NOSYMBOL, &bfd_abs_section,
		   TOS.value = ieee->section_table[section_n]->vma +
		   ieee_per_section(ieee->section_table[section_n])->pc);
	      break;
	    }
	case ieee_variable_L_enum:
	  /* L variable  address of section N */
	  next_byte(&(ieee->h));
	  PUSH(NOSYMBOL,ieee->section_table[must_parse_int(&(ieee->h))],0);
	  break;
	case ieee_variable_R_enum:
	  /* R variable, logical address of section module */
	  /* FIXME, this should be different to L */
	  next_byte(&(ieee->h));
	  PUSH(NOSYMBOL,ieee->section_table[must_parse_int(&(ieee->h))],0);
	  break;
	case ieee_variable_S_enum:
	  /* S variable, size in MAUS of section module */
	  next_byte(&(ieee->h));
	  PUSH(NOSYMBOL,
	       0,
	       ieee->section_table[must_parse_int(&(ieee->h))]->_raw_size);
	  break;
	  case ieee_variable_I_enum:
	case ieee_variable_X_enum:
	  /* Push the address of external variable n */
	    {
	      ieee_symbol_index_type sy;
	      next_byte(&(ieee->h));
	      sy.index  = (int)(must_parse_int(&(ieee->h))) ;
	      sy.letter = 'X';

	      PUSH(sy, &bfd_und_section, 0);
	    }	
	  break;
	case ieee_function_minus_enum:
	    {
	      bfd_vma value1, value2;
	      asection *section1, *section_dummy;
	      ieee_symbol_index_type sy;
	      next_byte(&(ieee->h));

	      POP(sy, section1, value1);
	      POP(sy, section_dummy, value2);
	      PUSH(sy, section1 ? section1 : section_dummy, value1-value2);
	    }
	  break;
	case ieee_function_plus_enum:
	    {
	      bfd_vma value1, value2;
	      asection *section1;
	      asection *section2;
	      ieee_symbol_index_type sy1;
	      ieee_symbol_index_type sy2;
	      next_byte(&(ieee->h));

	      POP(sy1, section1, value1);
	      POP(sy2, section2, value2);
	      PUSH(sy1.letter ? sy1 : sy2, section1!=&bfd_abs_section ? section1: section2, value1+value2);
	    }
	  break;
	default: 
	    {
	      bfd_vma va;
	      BFD_ASSERT(this_byte(&(ieee->h)) < (int)ieee_variable_A_enum 
			 || this_byte(&(ieee->h)) > (int)ieee_variable_Z_enum);
	      if (parse_int(&(ieee->h), &va)) 
		  {
		    PUSH(NOSYMBOL, &bfd_abs_section, va);
		  }
	      else {
		/* 
		  Thats all that we can understand. As far as I can see
		  there is a bug in the Microtec IEEE output which I'm
		  using to scan, whereby the comma operator is ommited
		  sometimes in an expression, giving expressions with too
		  many terms. We can tell if that's the case by ensuring
		  that sp == stack here. If not, then we've pushed
		  something too far, so we keep adding
		  */

		while (sp != stack+1) {
		  asection *section1;
		  ieee_symbol_index_type sy1;
		  POP(sy1, section1, *extra);
		}
	      {
		asection *dummy;

		POP(*symbol, dummy, *value);
		if (section) *section = dummy;
	      }
		
		loop = false;
	      }
	    }

	}
  }
}



#define ieee_seek(abfd, offset) \
  IEEE_DATA(abfd)->h.input_p = IEEE_DATA(abfd)->h.first_byte + offset

#define ieee_pos(abfd)   IEEE_DATA(abfd)->h.input_p -IEEE_DATA(abfd)->h.first_byte 

static unsigned int last_index;

static ieee_symbol_type *
DEFUN(get_symbol,(abfd, 
		  ieee,  
		  last_symbol,
		  symbol_count,
pptr,
max_index
		  ),
      bfd *abfd AND
      ieee_data_type *ieee AND
      ieee_symbol_type *last_symbol AND
      unsigned int *symbol_count AND
		  ieee_symbol_type *** pptr AND
      unsigned int *max_index