text: /*	$NetBSD: md.c,v 1.6 1994/11/30 06:20:42 phil Exp $  */
  /*
   * Copyright (c) 1993 Paul Kranenburg
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *      This product includes software developed by Paul Kranenburg.
   * 4. The name of the author may not be used to endorse or promote products
   *    derived from this software without specific prior written permission
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   */
  
  #include <sys/param.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <sys/types.h>
  #include <fcntl.h>
  #include <a.out.h>
  #include <stab.h>
  #include <string.h>
  
  #include "ld.h"
  
  /*
   * Put little endian VAL of size N at ADDR
   */
  static void
  put_num(addr, val, n)
  unsigned char	*addr;
  long		val;
  char		n;
  {
  	while (n--) {
  		*addr++ = val;
  		val >>= 8;
  	}
  }
  
  /*
   * Get little endian of size N at ADDR
   */
  static unsigned long
  get_num(addr, n)
  unsigned char	*addr;
  int		n;
  {
  	int val = 0;
  
  	addr += (n - 1);
  	while (n--)
  		val = val * 256 + *addr--;
  
  	return val;
  }
  
  /*
   * Put big endian VAL of size N at ADDR
   */
  static void
  put_imm(addr, val, n)
  unsigned char	*addr;
  unsigned long	val;
  char    	n;
  {
  	addr += (n - 1);
  	while (n--) {
  		*addr-- = val;
  		val >>= 8;
  	}
  }
  
  /*
   * Get big endian of size N at ADDR
   */
  static unsigned long
  get_imm(addr, n)
  unsigned char	*addr;
  int 		n;
  {
  	int val = 0;
  
  	while (n--)
    		val = val * 256 + *addr++;
  
  	return val;
  }
  
  /*
   * Displacements are big endian with the size
   * encoded in the two top bits:
   * Byte:	0xxxxxxx
   * Word:	10xxxxxx xxxxxxxx
   * Double word:	11xxxxxx xxxxxxxx xxxxxxxx xxxxxxxx
   */
  
  /*
   * Signextend VAL from bit N
   */
  static long
  sign_extend(val, n)
  int	val, n;
  {
  	val = val & ((1 << n) - 1);
  	return (val & (1 << (n - 1))?
  			val | (~((1 << n) - 1))
  		:
  			val
  		);
  }
  
  /*
   * Put ns32k displacement VAL of size N at ADDR
   */
  static void
  put_disp(addr, val, n)
  unsigned char	*addr;
  long		val;
  char		n;
  {
  	switch (n) {
  	case 1:
  		if (val < -64 || val > 63)
  			warnx("Byte displacement %d, out of range.", val);
  		val &= 0x7f;
  		*addr++ = val;
  		break;
  	case 2:
  		if (val < -8192 || val > 8191)
  			warnx("Word displacement %d, out of range.", val);
  		val &= 0x3fff;
  		val |= 0x8000;
  		*addr++ = (val >> 8);
  		*addr++ = val;
  		break;
  	case 4:
  #if 1
  		if (val < -0x1f000000 || val >= 0x20000000)
  #else
  		if (val < -0x20000000 || val >= 0x20000000)
  #endif
  			warnx("Double word displacement %d, out of range", val);
  		val |= 0xc0000000;
  		*addr++ = (val >> 24);
  		*addr++ = (val >> 16);
  		*addr++ = (val >> 8);
  		*addr++ = val;
  		break;
  	default:
  		errx(1, "internal error: putdisp: n = %d", n);
  	}
  }
  
  /*
   * Get ns32k displacement size N at ADDR
   */
  static unsigned long
  get_disp(addr, n)
  unsigned char	*addr;
  int		n;
  {
  	unsigned long Ivalue;
  
  	Ivalue = *addr++ & 0xff;
  	if (n == 0) {
  		if (Ivalue & 0x80) {
  			if (Ivalue & 0x40)
  				n = 4;
  			else
  				n = 2;
  		} else
  			n = 1;
  	}
  
  	switch (n) {
  	case 1:
  		Ivalue = sign_extend(Ivalue, 7);
  		break;
  	case 2:
  		Ivalue = sign_extend(Ivalue, 6);
  		Ivalue = (Ivalue << 8) | *addr;
  		break;
  	case 4:
  		Ivalue = sign_extend (Ivalue, 6);
  		Ivalue = (Ivalue << 8) | *addr++;
  		Ivalue = (Ivalue << 8) | *addr++;
  		Ivalue = (Ivalue << 8) | *addr;
  		break;
  	default:
  		errx(1, "get_disp: invalid argument %d\n", n);
  	}
  	return Ivalue;
  }
  
  /*
   * Get relocation addend corresponding to relocation record RP
   * from address ADDR
   */
  long
  md_get_addend(rp, addr)
  struct relocation_info	*rp;
  unsigned char		*addr;
  {
  	int bytes = 1 << RELOC_TARGET_SIZE(rp);
  
  	switch (rp->r_disp) {
  	case 0:
  		return get_imm(addr, bytes);
  	case 1:
  		return get_disp(addr, bytes);
  	case 2:
  		return get_num(addr, bytes);
  	}
  }
  
  /*
   * Put RELOCATION at ADDR according to relocation record RP.
   */
  void
  md_relocate(rp, relocation, addr, relocatable_output)
  struct relocation_info	*rp;
  long			relocation;
  unsigned char		*addr;
  {
  	int bytes = 1 << RELOC_TARGET_SIZE(rp);
  
  	switch (rp->r_disp) {
  	case 0:
  		return put_imm(addr, relocation, bytes);
  	case 1:
  		return put_disp(addr, relocation, bytes);
  	case 2:
  		return put_num(addr, relocation, bytes);
  	}
  #ifdef RTLD
  	_cachectl (addr, bytes); /* maintain cache coherency */
  #endif
  }
  
  /*
   * Machine dependent part of claim_rrs_reloc().
   * Set RRS relocation type.
   */
  int
  md_make_reloc(rp, r, type)
  struct relocation_info	*rp, *r;
  int			type;
  {
  	/* Relocation size */
  	r->r_length = rp->r_length;
  
  	/* Data type */
  	r->r_disp = rp->r_disp;
  
  	if (RELOC_PCREL_P(rp))
  		r->r_pcrel = 1;
  
  	if (type & RELTYPE_RELATIVE)
  		r->r_relative = 1;
  
  	if (type & RELTYPE_COPY)
  		r->r_copy = 1;
  
  	return 0;
  }
  
  /*
   * Set up a transfer from jmpslot at OFFSET (relative to the PLT table)
   * to the binder slot (which is at offset 0 of the PLT).
   */
  void
  md_make_jmpslot(sp, offset, index)
  jmpslot_t	*sp;
  long		offset;
  long		index;
  {
  	/*
  	 * On ns32k machines, a long branch offset is relative to
  	 * the address of the branch instruction.
  	 */
  
  	put_num(sp->code, BSR, 2);
  	put_disp(sp->code + 2, -offset - 1, 4);
  	sp->reloc_index = index;
  #ifdef RTLD
  	_cachectl (sp->code, 6);	/* maintain cache coherency */
  #endif
  }
  
  /*
   * Set up a "direct" transfer (ie. not through the run-time binder) from
   * jmpslot at OFFSET to ADDR. Used by `ld' when the SYMBOLIC flag is on,
   * and by `ld.so' after resolving the symbol.
   * On the ns32k, we use the BR instruction which is PC relative, so no
   * further RRS relocations will be necessary for such a jmpslot.
   */
  void
  md_fix_jmpslot(sp, offset, addr)
  jmpslot_t	*sp;
  long		offset;
  u_long		addr;
  {
  	put_num(sp->code, BR, 2);
  	put_disp(sp->code + 2, addr - offset - 1, 4);
  	sp->reloc_index = 0;
  #ifdef RTLD
  	_cachectl (sp->code, 6);	/* maintain cache coherency */
  #endif
  }
  
  /*
   * Update the relocation record for a RRS jmpslot.
   */
  void
  md_make_jmpreloc(rp, r, type)
  struct relocation_info	*rp, *r;
  int			type;
  {
  	jmpslot_t	*sp;
  
  	/*
  	 * Fix relocation address to point to the correct
  	 * location within this jmpslot.
  	 */
  	r->r_address++;
  
  	/* Relocation size */
  	r->r_length = 2;
  
  	/* Data type */
  	r->r_disp = 1;
  
  	/* Set relocation type */
  	r->r_jmptable = 1;
  
  	if (type & RELTYPE_RELATIVE)
  		r->r_relative = 1;
  }
  
  /*
   * Set relocation type for a RRS GOT relocation.
   */
  void
  md_make_gotreloc(rp, r, type)
  struct relocation_info	*rp, *r;
  int			type;
  {
  	r->r_baserel = 1;
  	if (type & RELTYPE_RELATIVE)
  		r->r_relative = 1;
  
  	/* Relocation size */
  	r->r_length = 2;
  
  	/* Data type */
  	r->r_disp = 2;
  }
  
  /*
   * Set relocation type for a RRS copy operation.
   */
  void
  md_make_cpyreloc(rp, r)
  struct relocation_info	*rp, *r;
  {
  	/* Relocation size */
  	r->r_length = 2;
  
  	/* Data type */
  	r->r_disp = 2;
  
  	r->r_copy = 1;
  }
  
  void
  md_set_breakpoint(where, savep)
  long	where;
  long	*savep;
  {
  	*savep = *(long *)where;
  	*(short *)where = BPT;
  }
  
  #ifndef RTLD
  /*
   * Initialize (output) exec header such that useful values are
   * obtained from subsequent N_*() macro evaluations.
   */
  void
  md_init_header(hp, magic, flags)
  struct exec	*hp;
  int		magic, flags;
  {
  	if (oldmagic)
  		hp->a_midmag = oldmagic;
  	else
  		N_SETMAGIC((*hp), magic, MID_MACHINE, flags);
  
  	/* TEXT_START depends on the value of outheader.a_entry.  */
  	if (!(link_mode & SHAREABLE))
  		hp->a_entry = PAGSIZ;
  }
  #endif /* RTLD */
  
  
  #ifdef NEED_SWAP
  /*
   * Byte swap routines for cross-linking.
   */
  
  void
  md_swapin_exec_hdr(h)
  struct exec *h;
  {
  	int skip = 0;
  
  	if (!N_BADMAG(*h))
  		skip = 1;
  
  	swap_longs((long *)h + skip, sizeof(*h)/sizeof(long) - skip);
  }
  
  void
  md_swapout_exec_hdr(h)
  struct exec *h;
  {
  	/* NetBSD/OpenBSD: Always leave magic alone */
  	int skip = 1;
  #if 0
  	if (N_GETMAGIC(*h) == OMAGIC)
  		skip = 0;
  #endif
  
  	swap_longs((long *)h + skip, sizeof(*h)/sizeof(long) - skip);
  }
  
  
  void
  md_swapin_reloc(r, n)
  struct relocation_info *r;
  int n;
  {
  	int	bits;
  
  	for (; n; n--, r++) {
  		r->r_address = md_swap_long(r->r_address);
  		bits = ((int *)r)[1];
  		r->r_symbolnum = md_swap_long(bits) & 0xffffff;
  		bits = ((unsigned char *)r)[7];
  		r->r_pcrel = ((bits >> 7) & 1);
  		r->r_length = ((bits >> 5) & 3);
  		r->r_extern = ((bits >> 4) & 1);
  		r->r_baserel = ((bits >> 3) & 1);
  		r->r_jmptable = ((bits >> 2) & 1);
  		r->r_relative = ((bits >> 1) & 1);
  #ifdef N_SIZE
  		r->r_copy = (bits & 1);
  #endif
  	}
  }
  
  void
  md_swapout_reloc(r, n)
  struct relocation_info *r;
  int n;
  {
  	int	bits;
  
  	for (; n; n--, r++) {
  		r->r_address = md_swap_long(r->r_address);
  		((int *)r)[1] = md_swap_long(r->r_symbolnum & 0xffffff00);
  		bits = ((r->r_pcrel << 7) & 0x80);
  		bits |= ((r->r_length << 5) & 0x60);
  		bits |= ((r->r_extern << 4) & 0x10);
  		bits |= ((r->r_baserel << 3) & 8);
  		bits |= ((r->r_jmptable << 2) & 4);
  		bits |= ((r->r_relative << 1) & 2);
  #ifdef N_SIZE
  		bits |= (r->r_copy & 1);
  #endif
  		((unsigned char *)r)[7] = bits;
  	}
  }
  
  void
  md_swapout_jmpslot(j, n)
  jmpslot_t	*j;
  int		n;
  {
  	for (; n; n--, j++) {
  		j->opcode = md_swap_short(j->opcode);
  		j->addr[0] = md_swap_short(j->addr[0]);
  		j->addr[1] = md_swap_short(j->addr[1]);
  		j->reloc_index = md_swap_short(j->reloc_index);
  	}
  }
  
  #endif /* NEED_SWAP */
  