include/a.out.encap.h

   1 /* Another try at encapsulating bsd object files in coff.
   2    Copyright (C) 1988, 1989, Free Software Foundation, Inc.
   3    Written by Pace Willisson 12/9/88
   4
   5    This file is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 1, or (at your option)
   8    any later version.
   9
  10    This file is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this file; if not, write to the Free Software
  17    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  18
  19 /*
  20  * This time, we will only use the coff headers to tell the kernel
  21  * how to exec the file.  Therefore, the only fields that need to
  22  * be filled in are the scnptr and vaddr for the text and data
  23  * sections, and the vaddr for the bss.  As far as coff is concerned,
  24  * there is no symbol table, relocation, or line numbers.
  25  *
  26  * A normal bsd header (struct exec) is placed after the coff headers,
  27  * and before the real text.  I defined a the new fields 'a_machtype'
  28  * and a_flags.  If a_machtype is M_386, and a_flags & A_ENCAP is
  29  * true, then the bsd header is preceeded by a coff header.  Macros
  30  * like N_TXTOFF and N_TXTADDR use this field to find the bsd header.
  31  *
  32  * The only problem is to track down the bsd exec header.  The
  33  * macros HEADER_OFFSET, etc do this.  Look at nm.c, dis.c, etc
  34  * for examples.
  35  */
  36 #ifndef A_OUT_ENCAP_H_SEEN
  37 #define A_OUT_ENCAP_H_SEEN
  38
  39 #include "a.out.gnu.h"
  40
  41 /* Figure out what our target machine is */
  42 #include "target.h"
  43
  44 #define N_FLAGS_COFF_ENCAPSULATE 0x20 /* coff header precedes bsd header */
  45
  46 /* Describe the COFF header used for encapsulation.  */
  47
  48 struct coffheader
  49 {
  50   /* filehdr */
  51   unsigned short f_magic;
  52   unsigned short f_nscns;
  53   long f_timdat;
  54   long f_symptr;
  55   long f_nsyms;
  56   unsigned short f_opthdr;
  57   unsigned short f_flags;
  58   /* aouthdr */
  59   short magic;
  60   short vstamp;
  61   long tsize;
  62   long dsize;
  63   long bsize;
  64   long entry;
  65   long text_start;
  66   long data_start;
  67   struct coffscn
  68     {
  69       char s_name[8];
  70       long s_paddr;
  71       long s_vaddr;
  72       long s_size;
  73       long s_scnptr;
  74       long s_relptr;
  75       long s_lnnoptr;
  76       unsigned short s_nreloc;
  77       unsigned short s_nlnno;
  78       long s_flags;
  79     } scns[3];          /* text, data, bss */
  80 };
  81 \f
  82 /* Describe some of the parameters of the encapsulation,
  83    including how to find the encapsulated BSD header.  */
  84
  85 #if TARGET == TARGET_I386
  86 #define COFF_MAGIC 0514 /* I386MAGIC */
  87 #endif
  88 #if TARGET == TARGET_M68K
  89 #define COFF_MAGIC 0520 /* MC68MAGIC */
  90 #endif
  91 #if TARGET == TARGET_SPARC
  92 #define COFF_MAGIC UNKNOWN!!!   /* Used by TTI */
  93 #endif
  94 #if TARGET == TARGET_AM29K
  95 #define COFF_MAGIC 0x17A        /* Used by asm29k cross-tools */
  96 #endif
  97
  98 #ifdef COFF_MAGIC
  99 short __header_offset_temp;
 100
 101 /* FIXME, this is dumb.  The same tools can't handle a.outs for different
 102    architectures, just because COFF_MAGIC is different; so you need a
 103    separate GNU nm for every architecture!!?  Also note that for
 104    expediency, this macros accepts COFF_MAGIC in either byte order.
 105    The right thing to do is to call read_aout_header to handle all this.  */
 106
 107 #define HEADER_OFFSET(f) \
 108         (__header_offset_temp = 0, \
 109          fread ((char *)&__header_offset_temp, sizeof (short), 1, (f)), \
 110          fseek ((f), -sizeof (short), 1), \
 111          (__header_offset_temp==COFF_MAGIC || __header_offset_temp == \
 112             ((COFF_MAGIC >> 8)|((COFF_MAGIC&0xFF)<<8)) \
 113                     ? sizeof(struct coffheader) : 0))
 114
 115 #define HEADER_OFFSET_FD(fd) \
 116         (__header_offset_temp = 0, \
 117          read (fd, (char *)&__header_offset_temp, sizeof (short)), \
 118          lseek ((fd), -sizeof (short), 1), \
 119          (__header_offset_temp==COFF_MAGIC || __header_offset_temp == \
 120             ((COFF_MAGIC >> 8)|((COFF_MAGIC&0xFF)<<8)) \
 121                     ? sizeof(struct coffheader) : 0))
 122
 123
 124 #else
 125 #define HEADER_OFFSET(f) 0
 126 #define HEADER_OFFSET_FD(fd) 0
 127 #endif
 128
 129 #define HEADER_SEEK(f) (fseek ((f), HEADER_OFFSET((f)), 1))
 130 #define HEADER_SEEK_FD(fd) (lseek ((fd), HEADER_OFFSET_FD((fd)), 1))
 131
 132 \f
 133 /* Describe the characteristics of the BSD header
 134    that appears inside the encapsulation.  */
 135
 136 #undef _N_HDROFF
 137 #undef N_TXTADDR
 138 #undef N_DATADDR
 139
 140 /* Encapsulated coff files that are linked ZMAGIC have a text segment
 141    offset just past the header (and a matching TXTADDR), excluding
 142    the headers from the text segment proper but keeping the physical
 143    layout and the virtual memory layout page-aligned.
 144
 145    Non-encapsulated a.out files that are linked ZMAGIC have a text
 146    segment that starts at 0 and an N_TXTADR similarly offset to 0.
 147    They too are page-aligned with each other, but they include the
 148    a.out header as part of the text.
 149
 150    The _N_HDROFF gets sizeof struct exec added to it, so we have
 151    to compensate here.  See <a.out.gnu.h>.  */
 152
 153 #define _N_HDROFF(x) ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \
 154                       sizeof (struct coffheader) : -sizeof (struct exec))
 155
 156 /* Address of text segment in memory after it is loaded.  */
 157 #define N_TXTADDR(x) \
 158         (TEXT_START_ADDR + \
 159         ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \
 160          sizeof (struct coffheader) + sizeof (struct exec) : 0))
 161
 162 /* I have no idea what this is doing here.  -- gnu@toad.com  20Mar90
 163    Perhaps it is to give a size that is acceptable to any machine?  */
 164 #undef SEGMENT_SIZE
 165 #define SEGMENT_SIZE 0x400000
 166
 167 #define N_DATADDR(x) \
 168         ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \
 169          (SEGMENT_SIZE + ((N_TXTADDR(x)+(x).a_text-1) & ~(SEGMENT_SIZE-1))) : \
 170          (N_TXTADDR(x)+(x).a_text))
 171
 172 #endif /* A_OUT_ENCAP_H_SEEN */