/* BFD back-end for WDC 65816 COFF binaries.
   Copyright (C) 1995-2018 Free Software Foundation, Inc.
   Written by Steve Chamberlain, <sac@cygnus.com>.

   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 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., 51 Franklin Street - Fifth Floor, Boston,
   MA 02110-1301, USA.  */

#include "sysdep.h"
#include "bfd.h"
#include "libbfd.h"
#include "bfdlink.h"
#include "coff/w65.h"
#include "coff/internal.h"
#include "libcoff.h"

#define COFF_DEFAULT_SECTION_ALIGNMENT_POWER (1)
static reloc_howto_type howto_table[] =
{
  HOWTO (R_W65_ABS8,    0,  0, 8,  FALSE, 0, complain_overflow_bitfield, 0, "abs8", TRUE, 0x000000ff, 0x000000ff, FALSE),
  HOWTO (R_W65_ABS16,   1,  0, 16, FALSE, 0, complain_overflow_bitfield, 0, "abs16", TRUE, 0x0000ffff, 0x0000ffff, FALSE),
  HOWTO (R_W65_ABS24,   0,  2, 32, FALSE, 0, complain_overflow_bitfield, 0, "abs24", TRUE, 0x00ffffff, 0x00ffffff, FALSE),
  HOWTO (R_W65_ABS8S8,  0,  0, 8,  FALSE, 0, complain_overflow_bitfield, 0, ">abs8", TRUE, 0x000000ff, 0x000000ff, FALSE),
  HOWTO (R_W65_ABS8S16, 0,  0, 8,  FALSE, 0, complain_overflow_bitfield, 0, "^abs8", TRUE, 0x000000ff, 0x000000ff, FALSE),
  HOWTO (R_W65_ABS16S8, 1,  0, 16, FALSE, 0, complain_overflow_bitfield, 0, ">abs16", TRUE, 0x0000ffff, 0x0000ffff, FALSE),
  HOWTO (R_W65_ABS16S16,1,  0, 16, FALSE, 0, complain_overflow_bitfield, 0, "^abs16", TRUE, 0x0000ffff, 0x0000ffff, FALSE),
  HOWTO (R_W65_PCR8,    0,  0, 8,  FALSE, 0, complain_overflow_bitfield, 0, "pcrel8", TRUE, 0x000000ff, 0x000000ff, TRUE),
  HOWTO (R_W65_PCR16,   1,  0, 16, FALSE, 0, complain_overflow_bitfield, 0, "pcrel16", TRUE, 0x0000ffff, 0x0000ffff, TRUE),
  HOWTO (R_W65_DP,      0,  0, 8,  FALSE, 0, complain_overflow_bitfield, 0, "dp", TRUE, 0x000000ff, 0x000000ff, FALSE),
};

#define NUM_HOWTOS (sizeof (howto_table) / sizeof (howto_table[0]))

/* Turn a howto into a reloc number.  */

#define SELECT_RELOC(x,howto) \
  { x.r_type = select_reloc(howto); }

#define BADMAG(x) (W65BADMAG(x))
#define W65 1			/* Customize coffcode.h */
#define __A_MAGIC_SET__

/* Code to swap in the reloc */
#define SWAP_IN_RELOC_OFFSET	H_GET_32
#define SWAP_OUT_RELOC_OFFSET	H_PUT_32
#define SWAP_OUT_RELOC_EXTRA(abfd, src, dst) \
  dst->r_stuff[0] = 'S'; \
  dst->r_stuff[1] = 'C';

static int
select_reloc (reloc_howto_type *howto)
{
  return howto->type;
}

/* Code to turn a r_type into a howto ptr, uses the above howto table.  */

static void
rtype2howto (arelent *internal,
	     struct internal_reloc *dst)
{
  if (dst->r_type > 0 && dst->r_type <= NUM_HOWTOS)
    internal->howto = howto_table + dst->r_type - 1;
  else
    internal->howto = NULL;
}

#define RTYPE2HOWTO(internal, relocentry) rtype2howto(internal,relocentry)

/* Perform any necessary magic to the addend in a reloc entry.  */

#define CALC_ADDEND(abfd, symbol, ext_reloc, cache_ptr) \
 cache_ptr->addend =  ext_reloc.r_offset;

#define RELOC_PROCESSING(relent,reloc,symbols,abfd,section) \
 reloc_processing(relent, reloc, symbols, abfd, section)

static void
reloc_processing (arelent * relent,
		  struct internal_reloc *reloc,
		  asymbol ** symbols,
		  bfd * abfd,
		  asection * section)
{
  relent->address = reloc->r_vaddr;
  rtype2howto (relent, reloc);

  if (((int) reloc->r_symndx) > 0)
    relent->sym_ptr_ptr = symbols + obj_convert (abfd)[reloc->r_symndx];
  else
    relent->sym_ptr_ptr = (asymbol **) bfd_abs_section_ptr->symbol_ptr_ptr;

  relent->addend = reloc->r_offset;

  relent->address -= section->vma;
  /*  relent->section = 0;*/
}

static int
w65_reloc16_estimate (bfd *abfd,
		      asection *input_section,
		      arelent *reloc,
		      unsigned int shrink,
		      struct bfd_link_info *link_info)
{
  bfd_vma value;
  bfd_vma dot;
  bfd_vma gap;

  /* The address of the thing to be relocated will have moved back by
     the size of the shrink  - but we don't change reloc->address here,
     since we need it to know where the relocation lives in the source
     uncooked section.  */

  /*  reloc->address -= shrink;   conceptual */

  bfd_vma address = reloc->address - shrink;

  switch (reloc->howto->type)
    {
    case R_MOV16B2:
    case R_JMP2:
      shrink+=2;
      break;

      /* Thing is a move one byte.  */
    case R_MOV16B1:
      value = bfd_coff_reloc16_get_value (reloc, link_info, input_section);

      if (value >= 0xff00)
	{
	  /* Change the reloc type from 16bit, possible 8 to 8bit
	     possible 16.  */
	  reloc->howto = reloc->howto + 1;
	  /* The place to relc moves back by one.  */
	  /* This will be two bytes smaller in the long run.  */
	  shrink += 2;
	  bfd_perform_slip (abfd, 2, input_section, address);
	}

      break;
      /* This is the 24 bit branch which could become an 8 bitter,
	 the relocation points to the first byte of the insn, not the
	 actual data.  */

    case R_JMPL1:
      value = bfd_coff_reloc16_get_value (reloc, link_info, input_section);

      dot = input_section->output_section->vma +
	input_section->output_offset + address;

      /* See if the address we're looking at within 127 bytes of where
	 we are, if so then we can use a small branch rather than the
	 jump we were going to.  */
      gap = value - dot;

      if (-120 < (long) gap && (long) gap < 120)
	{
	  /* Change the reloc type from 24bit, possible 8 to 8bit
	     possible 32.  */
	  reloc->howto = reloc->howto + 1;
	  /* This will be two bytes smaller in the long run.  */
	  shrink += 2;
	  bfd_perform_slip (abfd, 2, input_section, address);
	}
      break;

    case R_JMP1:
      value = bfd_coff_reloc16_get_value (reloc, link_info, input_section);

      dot = input_section->output_section->vma +
	input_section->output_offset + address;

      /* See if the address we're looking at within 127 bytes of where
	 we are, if so then we can use a small branch rather than the
	 jump we were going to.  */
      gap = value - (dot - shrink);

      if (-120 < (long) gap && (long) gap < 120)
	{
	  /* Change the reloc type from 16bit, possible 8 to 8bit
	     possible 16.  */
	  reloc->howto = reloc->howto + 1;
	  /* The place to relc moves back by one.  */

	  /* This will be two bytes smaller in the long run.  */
	  shrink += 2;
	  bfd_perform_slip (abfd, 2, input_section, address);
	}
      break;
    }

  return shrink;
}

/* First phase of a relaxing link.  */

/* Reloc types
   large		small
   R_MOV16B1		R_MOV16B2	mov.b with 16bit or 8 bit address
   R_JMP1		R_JMP2		jmp or pcrel branch
   R_JMPL1		R_JMPL_B8	24jmp or pcrel branch
   R_MOV24B1		R_MOV24B2	24 or 8 bit reloc for mov.b  */

static void
w65_reloc16_extra_cases (bfd *abfd,
			 struct bfd_link_info *link_info,
			 struct bfd_link_order *link_order,
			 arelent *reloc,
			 bfd_byte *data,
			 unsigned int *src_ptr,
			 unsigned int *dst_ptr)
{
  unsigned int src_address = *src_ptr;
  unsigned int dst_address = *dst_ptr;
  asection *input_section = link_order->u.indirect.section;

  switch (reloc->howto->type)
    {
    case R_W65_ABS8:
    case R_W65_DP:
      {
	unsigned int gap = bfd_coff_reloc16_get_value (reloc, link_info,
						       input_section);
	bfd_put_8 (abfd, gap, data + dst_address);
	dst_address += 1;
	src_address += 1;
      }
      break;

    case R_W65_ABS8S8:
      {
	unsigned int gap = bfd_coff_reloc16_get_value (reloc, link_info,
						       input_section);
	gap >>= 8;
	bfd_put_8 (abfd, gap, data + dst_address);
	dst_address += 1;
	src_address += 1;
      }
      break;

    case R_W65_ABS8S16:
      {
	unsigned int gap = bfd_coff_reloc16_get_value (reloc, link_info,
						       input_section);
	gap >>= 16;
	bfd_put_8 (abfd, gap, data + dst_address);
	dst_address += 1;
	src_address += 1;
      }
      break;

    case R_W65_ABS16:
      {
	unsigned int gap = bfd_coff_reloc16_get_value (reloc, link_info,
						       input_section);

	bfd_put_16 (abfd, (bfd_vma) gap, data + dst_address);
	dst_address += 2;
	src_address += 2;
      }
      break;
    case R_W65_ABS16S8:
      {
	unsigned int gap = bfd_coff_reloc16_get_value (reloc, link_info,
						       input_section);
	gap >>= 8;
	bfd_put_16 (abfd, (bfd_vma) gap, data + dst_address);
	dst_address += 2;
	src_address += 2;
      }
      break;
    case R_W65_ABS16S16:
      {
	unsigned int gap = bfd_coff_reloc16_get_value (reloc, link_info,
						       input_section);
	gap >>= 16;
	bfd_put_16 (abfd, (bfd_vma) gap, data + dst_address);
	dst_address += 2;
	src_address += 2;
      }
      break;

    case R_W65_ABS24:
      {
	unsigned int gap = bfd_coff_reloc16_get_value (reloc, link_info,
						       input_section);
	bfd_put_16 (abfd, (bfd_vma) gap, data + dst_address);
	bfd_put_8 (abfd, gap >> 16, data+dst_address + 2);
	dst_address += 3;
	src_address += 3;
      }
      break;

    case R_W65_PCR8:
      {
	int gap = bfd_coff_reloc16_get_value (reloc, link_info,
					      input_section);
	bfd_vma dot = (dst_address
		       + input_section->output_offset
		       + input_section->output_section->vma);

	gap -= dot + 1;
	if (gap < -128 || gap > 127)
	  (*link_info->callbacks->reloc_overflow)
	    (link_info, NULL, bfd_asymbol_name (*reloc->sym_ptr_ptr),
	     reloc->howto->name, reloc->addend, input_section->owner,
	     input_section, reloc->address);

	bfd_put_8 (abfd, gap, data + dst_address);
	dst_address += 1;
	src_address += 1;
      }
      break;

    case R_W65_PCR16:
      {
	bfd_vma gap = bfd_coff_reloc16_get_value (reloc, link_info,
						  input_section);
	bfd_vma dot = (dst_address
		       + input_section->output_offset
		       + input_section->output_section->vma);

	/* This wraps within the page, so ignore the relativeness, look at the
	   high part.  */
	if ((gap & 0xf0000) != (dot & 0xf0000))
	  (*link_info->callbacks->reloc_overflow)
	    (link_info, NULL, bfd_asymbol_name (*reloc->sym_ptr_ptr),
	     reloc->howto->name, reloc->addend, input_section->owner,
	     input_section, reloc->address);

	gap -= dot + 2;
	bfd_put_16 (abfd, gap, data + dst_address);
	dst_address += 2;
	src_address += 2;
      }
      break;
    default:
      printf (_("ignoring reloc %s\n"), reloc->howto->name);
      break;

    }
  *src_ptr = src_address;
  *dst_ptr = dst_address;
}

#define coff_reloc16_extra_cases w65_reloc16_extra_cases
#define coff_reloc16_estimate w65_reloc16_estimate

#ifndef bfd_pe_print_pdata
#define bfd_pe_print_pdata	NULL
#endif

#include "coffcode.h"

#undef coff_bfd_get_relocated_section_contents
#undef coff_bfd_relax_section
#define coff_bfd_get_relocated_section_contents \
  bfd_coff_reloc16_get_relocated_section_contents
#define coff_bfd_relax_section bfd_coff_reloc16_relax_section

CREATE_LITTLE_COFF_TARGET_VEC (w65_coff_vec, "coff-w65", BFD_IS_RELAXABLE, 0, '_', NULL, COFF_SWAP_TABLE)
