gas/config/obj-bout.h

   1 /* b.out object file format
   2    Copyright (C) 1989, 1990, 1991, 1992 Free Software Foundation, Inc.
   3
   4    This file is part of GAS, the GNU Assembler.
   5
   6    GAS is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as
   8    published by the Free Software Foundation; either version 2,
   9    or (at your option) any later version.
  10
  11    GAS is distributed in the hope that it will be useful, but
  12    WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  14    the GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public
  17    License along with GAS; see the file COPYING.  If not, write
  18    to the Free Software Foundation, 675 Mass Ave, Cambridge, MA
  19    02139, USA. */
  20
  21 /*
  22  * This file is a modified version of 'a.out.h'.  It is to be used in all GNU
  23  * tools modified to support the i80960 b.out format (or tools that operate on
  24  * object files created by such tools).
  25  *
  26  * All i80960 development is done in a CROSS-DEVELOPMENT environment.  I.e.,
  27  * object code is generated on, and executed under the direction of a symbolic
  28  * debugger running on, a host system.  We do not want to be subject to the
  29  * vagaries of which host it is or whether it supports COFF or a.out format, or
  30  * anything else.  We DO want to:
  31  *
  32  *      o always generate the same format object files, regardless of host.
  33  *
  34  *      o have an 'a.out' header that we can modify for our own purposes
  35  *        (the 80960 is typically an embedded processor and may require
  36  *        enhanced linker support that the normal a.out.h header can't
  37  *        accommodate).
  38  *
  39  * As for byte-ordering, the following rules apply:
  40  *
  41  *      o Text and data that is actually downloaded to the target is always
  42  *        in i80960 (little-endian) order.
  43  *
  44  *      o All other numbers (in the header, symbols, relocation directives)
  45  *        are in host byte-order:  object files CANNOT be lifted from a
  46  *        little-end host and used on a big-endian (or vice versa) without
  47  *        modification.
  48  * ==> THIS IS NO LONGER TRUE USING BFD.  WE CAN GENERATE ANY BYTE ORDER
  49  *     FOR THE HEADER, AND READ ANY BYTE ORDER.  PREFERENCE WOULD BE TO
  50  *     USE LITTLE-ENDIAN BYTE ORDER THROUGHOUT, REGARDLESS OF HOST.  <==
  51  *
  52  *      o The downloader ('comm960') takes care to generate a pseudo-header
  53  *        with correct (i80960) byte-ordering before shipping text and data
  54  *        off to the NINDY monitor in the target systems.  Symbols and
  55  *        relocation info are never sent to the target.
  56  */
  57
  58
  59 #define OBJ_BOUT 1
  60
  61 #include "targ-cpu.h"
  62
  63 /* We want \v. */
  64 #define BACKSLASH_V 1
  65
  66 #define OBJ_DEFAULT_OUTPUT_FILE_NAME    "b.out"
  67
  68 extern const short seg_N_TYPE[];
  69 extern const segT N_TYPE_seg[];
  70
  71 #define BMAGIC  0415
  72 /* We don't accept the following (see N_BADMAG macro).
  73  * They're just here so GNU code will compile.
  74  */
  75 #define OMAGIC  0407            /* old impure format */
  76 #define NMAGIC  0410            /* read-only text */
  77 #define ZMAGIC  0413            /* demand load format */
  78
  79 #ifndef DEFAULT_MAGIC_NUMBER_FOR_OBJECT_FILE
  80 #define DEFAULT_MAGIC_NUMBER_FOR_OBJECT_FILE    (BMAGIC)
  81 #endif /* DEFAULT_MAGIC_NUMBER_FOR_OBJECT_FILE */
  82
  83 /* FILE HEADER
  84  *      All 'lengths' are given as a number of bytes.
  85  *      All 'alignments' are for relinkable files only;  an alignment of
  86  *              'n' indicates the corresponding segment must begin at an
  87  *              address that is a multiple of (2**n).
  88  */
  89 struct exec
  90   {
  91     /* Standard stuff */
  92     unsigned long a_magic;      /* Identifies this as a b.out file      */
  93     unsigned long a_text;       /* Length of text                       */
  94     unsigned long a_data;       /* Length of data                       */
  95     unsigned long a_bss;        /* Length of runtime uninitialized data area */
  96     unsigned long a_syms;       /* Length of symbol table               */
  97     unsigned long a_entry;      /* Runtime start address                */
  98     unsigned long a_trsize;     /* Length of text relocation info       */
  99     unsigned long a_drsize;     /* Length of data relocation info       */
 100
 101     /* Added for i960 */
 102     unsigned long a_tload;      /* Text runtime load address            */
 103     unsigned long a_dload;      /* Data runtime load address            */
 104     unsigned char a_talign;     /* Alignment of text segment            */
 105     unsigned char a_dalign;     /* Alignment of data segment            */
 106     unsigned char a_balign;     /* Alignment of bss segment             */
 107     unsigned char a_relaxable;  /* Contains enough info to relax     */
 108   };
 109
 110 #define N_BADMAG(x)     (((x).a_magic)!=BMAGIC)
 111 #define N_TXTOFF(x)     ( sizeof(struct exec) )
 112 #define N_DATOFF(x)     ( N_TXTOFF(x) + (x).a_text )
 113 #define N_TROFF(x)      ( N_DATOFF(x) + (x).a_data )
 114 #define N_DROFF(x)      ( N_TROFF(x) + (x).a_trsize )
 115 #define N_SYMOFF(x)     ( N_DROFF(x) + (x).a_drsize )
 116 #define N_STROFF(x)     ( N_SYMOFF(x) + (x).a_syms )
 117
 118 /* A single entry in the symbol table
 119  */
 120 struct nlist
 121   {
 122     union
 123       {
 124         char *n_name;
 125         struct nlist *n_next;
 126         long n_strx;            /* Index into string table      */
 127       }
 128     n_un;
 129     unsigned char n_type;       /* See below                            */
 130     char n_other;               /* Used in i80960 support -- see below  */
 131     short n_desc;
 132     unsigned long n_value;
 133   };
 134
 135 typedef struct nlist obj_symbol_type;
 136
 137 /* Legal values of n_type
 138  */
 139 #define N_UNDF  0               /* Undefined symbol     */
 140 #define N_ABS   2               /* Absolute symbol      */
 141 #define N_TEXT  4               /* Text symbol          */
 142 #define N_DATA  6               /* Data symbol          */
 143 #define N_BSS   8               /* BSS symbol           */
 144 #define N_FN    31              /* Filename symbol      */
 145
 146 #define N_EXT   1               /* External symbol (OR'd in with one of above)  */
 147 #define N_TYPE  036             /* Mask for all the type bits                   */
 148 #define N_STAB  0340            /* Mask for all bits used for SDB entries       */
 149
 150 #ifndef CUSTOM_RELOC_FORMAT
 151 struct relocation_info
 152   {
 153     int r_address;              /* File address of item to be relocated */
 154     unsigned
 155       r_index:24,               /* Index of symbol on which relocation is based*/
 156       r_pcrel:1,                /* 1 => relocate PC-relative; else absolute
 157                  *      On i960, pc-relative implies 24-bit
 158                  *      address, absolute implies 32-bit.
 159                  */
 160       r_length:2,               /* Number of bytes to relocate:
 161                  *      0 => 1 byte
 162                  *      1 => 2 bytes
 163                  *      2 => 4 bytes -- only value used for i960
 164                  */
 165       r_extern:1, r_bsr:1,      /* Something for the GNU NS32K assembler */
 166       r_disp:1,                 /* Something for the GNU NS32K assembler */
 167       r_callj:1,                /* 1 if relocation target is an i960 'callj' */
 168       nuthin:1;                 /* Unused                               */
 169   };
 170
 171 #endif /* CUSTOM_RELOC_FORMAT */
 172
 173 /*
 174  *  Macros to extract information from a symbol table entry.
 175  *  This syntaxic indirection allows independence regarding a.out or coff.
 176  *  The argument (s) of all these macros is a pointer to a symbol table entry.
 177  */
 178
 179 /* Predicates */
 180 /* True if the symbol is external */
 181 #define S_IS_EXTERNAL(s)        ((s)->sy_symbol.n_type & N_EXT)
 182
 183 /* True if symbol has been defined, ie is in N_{TEXT,DATA,BSS,ABS} or N_EXT */
 184 #define S_IS_DEFINED(s)         ((S_GET_TYPE(s) != N_UNDF) || (S_GET_DESC(s) != 0))
 185 #define S_IS_REGISTER(s)        ((s)->sy_symbol.n_type == N_REGISTER)
 186
 187 /* True if a debug special symbol entry */
 188 #define S_IS_DEBUG(s)           ((s)->sy_symbol.n_type & N_STAB)
 189 /* True if a symbol is local symbol name */
 190 /* A symbol name whose name begin with ^A is a gas internal pseudo symbol
 191    nameless symbols come from .stab directives. */
 192 #define S_IS_LOCAL(s)           (S_GET_NAME(s) && \
 193                                  !S_IS_DEBUG(s) && \
 194                                  (S_GET_NAME(s)[0] == '\001' || \
 195                                   (S_LOCAL_NAME(s) && !flagseen['L'])))
 196 /* True if a symbol is not defined in this file */
 197 #define S_IS_EXTERN(s)          ((s)->sy_symbol.n_type & N_EXT)
 198 /* True if the symbol has been generated because of a .stabd directive */
 199 #define S_IS_STABD(s)           (S_GET_NAME(s) == NULL)
 200
 201 /* Accessors */
 202 /* The value of the symbol */
 203 #define S_GET_VALUE(s)          ((unsigned long) ((s)->sy_symbol.n_value))
 204 /* The name of the symbol */
 205 #define S_GET_NAME(s)           ((s)->sy_symbol.n_un.n_name)
 206 /* The pointer to the string table */
 207 #define S_GET_OFFSET(s)         ((s)->sy_symbol.n_un.n_strx)
 208 /* The type of the symbol */
 209 #define S_GET_TYPE(s)           ((s)->sy_symbol.n_type & N_TYPE)
 210 /* The numeric value of the segment */
 211 #define S_GET_SEGMENT(s)        (N_TYPE_seg[S_GET_TYPE(s)])
 212 /* The n_other expression value */
 213 #define S_GET_OTHER(s)          ((s)->sy_symbol.n_other)
 214 /* The n_desc expression value */
 215 #define S_GET_DESC(s)           ((s)->sy_symbol.n_desc)
 216
 217 /* Modifiers */
 218 /* Set the value of the symbol */
 219 #define S_SET_VALUE(s,v)        ((s)->sy_symbol.n_value = (unsigned long) (v))
 220 /* Assume that a symbol cannot be simultaneously in more than on segment */
 221 /* set segment */
 222 #define S_SET_SEGMENT(s,seg)    ((s)->sy_symbol.n_type &= ~N_TYPE,(s)->sy_symbol.n_type|=SEGMENT_TO_SYMBOL_TYPE(seg))
 223 /* The symbol is external */
 224 #define S_SET_EXTERNAL(s)       ((s)->sy_symbol.n_type |= N_EXT)
 225 /* The symbol is not external */
 226 #define S_CLEAR_EXTERNAL(s)     ((s)->sy_symbol.n_type &= ~N_EXT)
 227 /* Set the name of the symbol */
 228 #define S_SET_NAME(s,v)         ((s)->sy_symbol.n_un.n_name = (v))
 229 /* Set the offset in the string table */
 230 #define S_SET_OFFSET(s,v)       ((s)->sy_symbol.n_un.n_strx = (v))
 231 /* Set the n_other expression value */
 232 #define S_SET_OTHER(s,v)        ((s)->sy_symbol.n_other = (v))
 233 /* Set the n_desc expression value */
 234 #define S_SET_DESC(s,v)         ((s)->sy_symbol.n_desc = (v))
 235
 236 /* File header macro and type definition */
 237
 238 #define H_GET_FILE_SIZE(h)      (sizeof(struct exec) + \
 239                                  H_GET_TEXT_SIZE(h) + H_GET_DATA_SIZE(h) + \
 240                                  H_GET_SYMBOL_TABLE_SIZE(h) + \
 241                                  H_GET_TEXT_RELOCATION_SIZE(h) + \
 242                                  H_GET_DATA_RELOCATION_SIZE(h) + \
 243                                  (h)->string_table_size)
 244
 245 #define H_GET_HEADER_SIZE(h)            (sizeof(struct exec))
 246 #define H_GET_TEXT_SIZE(h)              ((h)->header.a_text)
 247 #define H_GET_DATA_SIZE(h)              ((h)->header.a_data)
 248 #define H_GET_BSS_SIZE(h)               ((h)->header.a_bss)
 249 #define H_GET_TEXT_RELOCATION_SIZE(h)   ((h)->header.a_trsize)
 250 #define H_GET_DATA_RELOCATION_SIZE(h)   ((h)->header.a_drsize)
 251 #define H_GET_SYMBOL_TABLE_SIZE(h)      ((h)->header.a_syms)
 252 #define H_GET_MAGIC_NUMBER(h)           ((h)->header.a_info)
 253 #define H_GET_ENTRY_POINT(h)            ((h)->header.a_entry)
 254 #define H_GET_STRING_SIZE(h)            ((h)->string_table_size)
 255 #define H_GET_LINENO_SIZE(h)            (0)
 256
 257 #ifdef EXEC_MACHINE_TYPE
 258 #define H_GET_MACHINE_TYPE(h)           ((h)->header.a_machtype)
 259 #endif /* EXEC_MACHINE_TYPE */
 260 #ifdef EXEC_VERSION
 261 #define H_GET_VERSION(h)                ((h)->header.a_version)
 262 #endif /* EXEC_VERSION */
 263
 264 #define H_SET_TEXT_SIZE(h,v)            ((h)->header.a_text = (v))
 265 #define H_SET_DATA_SIZE(h,v)            ((h)->header.a_data = (v))
 266 #define H_SET_BSS_SIZE(h,v)             ((h)->header.a_bss = (v))
 267
 268 #define H_SET_RELOCATION_SIZE(h,t,d)    (H_SET_TEXT_RELOCATION_SIZE((h),(t)),\
 269                                          H_SET_DATA_RELOCATION_SIZE((h),(d)))
 270
 271 #define H_SET_TEXT_RELOCATION_SIZE(h,v) ((h)->header.a_trsize = (v))
 272 #define H_SET_DATA_RELOCATION_SIZE(h,v) ((h)->header.a_drsize = (v))
 273 #define H_SET_SYMBOL_TABLE_SIZE(h,v)    ((h)->header.a_syms = (v) * \
 274                                          sizeof(struct nlist))
 275
 276 #define H_SET_MAGIC_NUMBER(h,v)         ((h)->header.a_magic = (v))
 277
 278 #define H_SET_ENTRY_POINT(h,v)          ((h)->header.a_entry = (v))
 279 #define H_SET_STRING_SIZE(h,v)          ((h)->string_table_size = (v))
 280 #ifdef EXEC_MACHINE_TYPE
 281 #define H_SET_MACHINE_TYPE(h,v)         ((h)->header.a_machtype = (v))
 282 #endif /* EXEC_MACHINE_TYPE */
 283 #ifdef EXEC_VERSION
 284 #define H_SET_VERSION(h,v)              ((h)->header.a_version = (v))
 285 #endif /* EXEC_VERSION */
 286
 287 /*
 288  * Current means for getting the name of a segment.
 289  * This will change for infinite-segments support (e.g. COFF).
 290  */
 291 #define segment_name(seg)  ( seg_name[(int)(seg)] )
 292 extern char *const seg_name[];
 293
 294 typedef struct
 295   {
 296     struct exec header;         /* a.out header */
 297     long string_table_size;     /* names + '\0' + sizeof(int) */
 298   }
 299
 300 object_headers;
 301
 302 /* unused hooks. */
 303 #define OBJ_EMIT_LINENO(a, b, c)        {;}
 304 #define obj_pre_write_hook(a)           {;}
 305
 306 #if __STDC__
 307 struct fix;
 308 void tc_aout_fix_to_chars (char *where, struct fix *fixP, relax_addressT segment_address);
 309 #else /* not __STDC__ */
 310 void tc_aout_fix_to_chars ();
 311 #endif /* not __STDC__ */
 312
 313 /*
 314  * Local Variables:
 315  * comment-column: 0
 316  * fill-column: 131
 317  * End:
 318  */
 319
 320 /* end of obj-bout.h */