gas/config/obj-bout.h

   1 /* b.out object file format
   2    Copyright (C) 1989, 90, 91, 92, 93, 94, 95, 1996
   3    Free Software Foundation, Inc.
   4
   5    This file is part of GAS, the GNU Assembler.
   6
   7    GAS is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as
   9    published by the Free Software Foundation; either version 2,
  10    or (at your option) any later version.
  11
  12    GAS is distributed in the hope that it will be useful, but
  13    WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  15    the GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public
  18    License along with GAS; see the file COPYING.  If not, write
  19    to the Free Software Foundation, 59 Temple Place - Suite 330, Cambridge, MA
  20    02139, USA. */
  21
  22 /*
  23  * This file is a modified version of 'a.out.h'.  It is to be used in all GNU
  24  * tools modified to support the i80960 b.out format (or tools that operate on
  25  * object files created by such tools).
  26  *
  27  * All i80960 development is done in a CROSS-DEVELOPMENT environment.  I.e.,
  28  * object code is generated on, and executed under the direction of a symbolic
  29  * debugger running on, a host system.  We do not want to be subject to the
  30  * vagaries of which host it is or whether it supports COFF or a.out format, or
  31  * anything else.  We DO want to:
  32  *
  33  *      o always generate the same format object files, regardless of host.
  34  *
  35  *      o have an 'a.out' header that we can modify for our own purposes
  36  *        (the 80960 is typically an embedded processor and may require
  37  *        enhanced linker support that the normal a.out.h header can't
  38  *        accommodate).
  39  *
  40  * As for byte-ordering, the following rules apply:
  41  *
  42  *      o Text and data that is actually downloaded to the target is always
  43  *        in i80960 (little-endian) order.
  44  *
  45  *      o All other numbers (in the header, symbols, relocation directives)
  46  *        are in host byte-order:  object files CANNOT be lifted from a
  47  *        little-end host and used on a big-endian (or vice versa) without
  48  *        modification.
  49  * ==> THIS IS NO LONGER TRUE USING BFD.  WE CAN GENERATE ANY BYTE ORDER
  50  *     FOR THE HEADER, AND READ ANY BYTE ORDER.  PREFERENCE WOULD BE TO
  51  *     USE LITTLE-ENDIAN BYTE ORDER THROUGHOUT, REGARDLESS OF HOST.  <==
  52  *
  53  *      o The downloader ('comm960') takes care to generate a pseudo-header
  54  *        with correct (i80960) byte-ordering before shipping text and data
  55  *        off to the NINDY monitor in the target systems.  Symbols and
  56  *        relocation info are never sent to the target.
  57  */
  58
  59
  60 #define OBJ_BOUT 1
  61
  62 #define OUTPUT_FLAVOR bfd_target_aout_flavour
  63
  64 #include "targ-cpu.h"
  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
 186 #define S_IS_COMMON(s) \
 187   (S_GET_TYPE (s) == N_UNDF && S_GET_VALUE (s) != 0)
 188
 189 #define S_IS_REGISTER(s)        ((s)->sy_symbol.n_type == N_REGISTER)
 190
 191 /* True if a debug special symbol entry */
 192 #define S_IS_DEBUG(s)           ((s)->sy_symbol.n_type & N_STAB)
 193 /* True if a symbol is local symbol name */
 194 #define S_IS_LOCAL(s)                                   \
 195   ((S_GET_NAME (s)                                      \
 196     && !S_IS_DEBUG (s)                                  \
 197     && (strchr (S_GET_NAME (s), '\001') != NULL         \
 198         || strchr (S_GET_NAME (s), '\002') != NULL      \
 199         || (S_LOCAL_NAME(s) && !flag_keep_locals)))     \
 200    || (flag_strip_local_absolute                        \
 201        && !S_IS_EXTERNAL(s)                             \
 202        && S_GET_SEGMENT(s) == absolute_section))
 203 /* True if a symbol is not defined in this file */
 204 #define S_IS_EXTERN(s)          ((s)->sy_symbol.n_type & N_EXT)
 205 /* True if the symbol has been generated because of a .stabd directive */
 206 #define S_IS_STABD(s)           (S_GET_NAME(s) == NULL)
 207
 208 /* Accessors */
 209 /* The name of the symbol */
 210 #define S_GET_NAME(s)           ((s)->sy_symbol.n_un.n_name)
 211 /* The pointer to the string table */
 212 #define S_GET_OFFSET(s)         ((s)->sy_symbol.n_un.n_strx)
 213 /* The type of the symbol */
 214 #define S_GET_TYPE(s)           ((s)->sy_symbol.n_type & N_TYPE)
 215 /* The numeric value of the segment */
 216 #define S_GET_SEGMENT(s)        (N_TYPE_seg[S_GET_TYPE(s)])
 217 /* The n_other expression value */
 218 #define S_GET_OTHER(s)          ((s)->sy_symbol.n_other)
 219 /* The n_desc expression value */
 220 #define S_GET_DESC(s)           ((s)->sy_symbol.n_desc)
 221
 222 /* Modifiers */
 223 /* Assume that a symbol cannot be simultaneously in more than on segment */
 224 /* set segment */
 225 #define S_SET_SEGMENT(s,seg)    ((s)->sy_symbol.n_type &= ~N_TYPE,(s)->sy_symbol.n_type|=SEGMENT_TO_SYMBOL_TYPE(seg))
 226 /* The symbol is external */
 227 #define S_SET_EXTERNAL(s)       ((s)->sy_symbol.n_type |= N_EXT)
 228 /* The symbol is not external */
 229 #define S_CLEAR_EXTERNAL(s)     ((s)->sy_symbol.n_type &= ~N_EXT)
 230 /* Set the name of the symbol */
 231 #define S_SET_NAME(s,v)         ((s)->sy_symbol.n_un.n_name = (v))
 232 /* Set the offset in the string table */
 233 #define S_SET_OFFSET(s,v)       ((s)->sy_symbol.n_un.n_strx = (v))
 234 /* Set the n_other expression value */
 235 #define S_SET_OTHER(s,v)        ((s)->sy_symbol.n_other = (v))
 236 /* Set the n_desc expression value */
 237 #define S_SET_DESC(s,v)         ((s)->sy_symbol.n_desc = (v))
 238 /* Set the n_type value */
 239 #define S_SET_TYPE(s,v)         ((s)->sy_symbol.n_type = (v))
 240
 241 /* File header macro and type definition */
 242
 243 #define H_GET_FILE_SIZE(h)      (sizeof(struct exec) + \
 244                                  H_GET_TEXT_SIZE(h) + H_GET_DATA_SIZE(h) + \
 245                                  H_GET_SYMBOL_TABLE_SIZE(h) + \
 246                                  H_GET_TEXT_RELOCATION_SIZE(h) + \
 247                                  H_GET_DATA_RELOCATION_SIZE(h) + \
 248                                  (h)->string_table_size)
 249
 250 #define H_GET_HEADER_SIZE(h)            (sizeof(struct exec))
 251 #define H_GET_TEXT_SIZE(h)              ((h)->header.a_text)
 252 #define H_GET_DATA_SIZE(h)              ((h)->header.a_data)
 253 #define H_GET_BSS_SIZE(h)               ((h)->header.a_bss)
 254 #define H_GET_TEXT_RELOCATION_SIZE(h)   ((h)->header.a_trsize)
 255 #define H_GET_DATA_RELOCATION_SIZE(h)   ((h)->header.a_drsize)
 256 #define H_GET_SYMBOL_TABLE_SIZE(h)      ((h)->header.a_syms)
 257 #define H_GET_MAGIC_NUMBER(h)           ((h)->header.a_info)
 258 #define H_GET_ENTRY_POINT(h)            ((h)->header.a_entry)
 259 #define H_GET_STRING_SIZE(h)            ((h)->string_table_size)
 260 #define H_GET_LINENO_SIZE(h)            (0)
 261
 262 #ifdef EXEC_MACHINE_TYPE
 263 #define H_GET_MACHINE_TYPE(h)           ((h)->header.a_machtype)
 264 #endif /* EXEC_MACHINE_TYPE */
 265 #ifdef EXEC_VERSION
 266 #define H_GET_VERSION(h)                ((h)->header.a_version)
 267 #endif /* EXEC_VERSION */
 268
 269 #define H_SET_TEXT_SIZE(h,v)            ((h)->header.a_text = (v))
 270 #define H_SET_DATA_SIZE(h,v)            ((h)->header.a_data = (v))
 271 #define H_SET_BSS_SIZE(h,v)             ((h)->header.a_bss = (v))
 272
 273 #define H_SET_RELOCATION_SIZE(h,t,d)    (H_SET_TEXT_RELOCATION_SIZE((h),(t)),\
 274                                          H_SET_DATA_RELOCATION_SIZE((h),(d)))
 275
 276 #define H_SET_TEXT_RELOCATION_SIZE(h,v) ((h)->header.a_trsize = (v))
 277 #define H_SET_DATA_RELOCATION_SIZE(h,v) ((h)->header.a_drsize = (v))
 278 #define H_SET_SYMBOL_TABLE_SIZE(h,v)    ((h)->header.a_syms = (v) * \
 279                                          sizeof(struct nlist))
 280
 281 #define H_SET_MAGIC_NUMBER(h,v)         ((h)->header.a_magic = (v))
 282
 283 #define H_SET_ENTRY_POINT(h,v)          ((h)->header.a_entry = (v))
 284 #define H_SET_STRING_SIZE(h,v)          ((h)->string_table_size = (v))
 285 #ifdef EXEC_MACHINE_TYPE
 286 #define H_SET_MACHINE_TYPE(h,v)         ((h)->header.a_machtype = (v))
 287 #endif /* EXEC_MACHINE_TYPE */
 288 #ifdef EXEC_VERSION
 289 #define H_SET_VERSION(h,v)              ((h)->header.a_version = (v))
 290 #endif /* EXEC_VERSION */
 291
 292 typedef struct
 293   {
 294     struct exec header;         /* a.out header */
 295     long string_table_size;     /* names + '\0' + sizeof(int) */
 296   }
 297
 298 object_headers;
 299
 300 /* unused hooks. */
 301 #define OBJ_EMIT_LINENO(a, b, c)        {;}
 302 #define obj_pre_write_hook(a)           {;}
 303
 304 #if __STDC__
 305 struct fix;
 306 #endif
 307 extern void tc_aout_fix_to_chars PARAMS ((char *where,
 308                                           struct fix *fixP,
 309                                           relax_addressT segment_address));
 310 extern void tc_bout_fix_to_chars PARAMS ((char *where,
 311                                           struct fix *fixP,
 312                                           relax_addressT segment_address));
 313
 314 #define AOUT_STABS
 315
 316 /* end of obj-bout.h */