gas/config/obj-bout.h

   1 /* b.out object file format
   2    Copyright (C) 1989, 1990, 1991 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 1,
   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 /* $Id$ */
  22
  23 /*
  24  * This file is a modified version of 'a.out.h'.  It is to be used in all GNU
  25  * tools modified to support the i80960 b.out format (or tools that operate on
  26  * object files created by such tools).
  27  *
  28  * All i80960 development is done in a CROSS-DEVELOPMENT environment.  I.e.,
  29  * object code is generated on, and executed under the direction of a symbolic
  30  * debugger running on, a host system.  We do not want to be subject to the
  31  * vagaries of which host it is or whether it supports COFF or a.out format, or
  32  * anything else.  We DO want to:
  33  *
  34  *      o always generate the same format object files, regardless of host.
  35  *
  36  *      o have an 'a.out' header that we can modify for our own purposes
  37  *        (the 80960 is typically an embedded processor and may require
  38  *        enhanced linker support that the normal a.out.h header can't
  39  *        accommodate).
  40  *
  41  * As for byte-ordering, the following rules apply:
  42  *
  43  *      o Text and data that is actually downloaded to the target is always
  44  *        in i80960 (little-endian) order.
  45  *
  46  *      o All other numbers (in the header, symbols, relocation directives)
  47  *        are in host byte-order:  object files CANNOT be lifted from a
  48  *        little-end host and used on a big-endian (or vice versa) without
  49  *        modification.
  50  *
  51  *      o The downloader ('comm960') takes care to generate a pseudo-header
  52  *        with correct (i80960) byte-ordering before shipping text and data
  53  *        off to the NINDY monitor in the target systems.  Symbols and
  54  *        relocation info are never sent to the target.
  55  */
  56
  57
  58 #define OBJ_BOUT 1
  59
  60 #include "targ-cpu.h"
  61
  62  /* bout uses host byte order for headers */
  63 #ifdef CROSS_COMPILE
  64 #undef CROSS_COMPILE
  65 #endif /* CROSS_COMPILE */
  66
  67  /* We want \v. */
  68 #define BACKSLASH_V 1
  69
  70 #define OBJ_DEFAULT_OUTPUT_FILE_NAME    "b.out"
  71
  72 extern const short seg_N_TYPE[];
  73 extern const segT  N_TYPE_seg[];
  74
  75 #define BMAGIC  0415
  76 /* We don't accept the following (see N_BADMAG macro).
  77  * They're just here so GNU code will compile.
  78  */
  79 #define OMAGIC  0407            /* old impure format */
  80 #define NMAGIC  0410            /* read-only text */
  81 #define ZMAGIC  0413            /* demand load format */
  82
  83 #ifndef DEFAULT_MAGIC_NUMBER_FOR_OBJECT_FILE
  84 #define DEFAULT_MAGIC_NUMBER_FOR_OBJECT_FILE    (BMAGIC)
  85 #endif /* DEFAULT_MAGIC_NUMBER_FOR_OBJECT_FILE */
  86
  87 /* FILE HEADER
  88  *      All 'lengths' are given as a number of bytes.
  89  *      All 'alignments' are for relinkable files only;  an alignment of
  90  *              'n' indicates the corresponding segment must begin at an
  91  *              address that is a multiple of (2**n).
  92  */
  93 struct exec {
  94         /* Standard stuff */
  95         unsigned long a_magic;  /* Identifies this as a b.out file      */
  96         unsigned long a_text;   /* Length of text                       */
  97         unsigned long a_data;   /* Length of data                       */
  98         unsigned long a_bss;    /* Length of runtime uninitialized data area */
  99         unsigned long a_syms;   /* Length of symbol table               */
 100         unsigned long a_entry;  /* Runtime start address                */
 101         unsigned long a_trsize; /* Length of text relocation info       */
 102         unsigned long a_drsize; /* Length of data relocation info       */
 103
 104         /* Added for i960 */
 105         unsigned long a_tload;  /* Text runtime load address            */
 106         unsigned long a_dload;  /* Data runtime load address            */
 107         unsigned char a_talign; /* Alignment of text segment            */
 108         unsigned char a_dalign; /* Alignment of data segment            */
 109         unsigned char a_balign; /* Alignment of bss segment             */
 110         unsigned char unused;   /* (Just to make struct size a multiple of 4) */
 111 };
 112
 113 #define N_BADMAG(x)     (((x).a_magic)!=BMAGIC)
 114 #define N_TXTOFF(x)     ( sizeof(struct exec) )
 115 #define N_DATOFF(x)     ( N_TXTOFF(x) + (x).a_text )
 116 #define N_TROFF(x)      ( N_DATOFF(x) + (x).a_data )
 117 #define N_DROFF(x)      ( N_TROFF(x) + (x).a_trsize )
 118 #define N_SYMOFF(x)     ( N_DROFF(x) + (x).a_drsize )
 119 #define N_STROFF(x)     ( N_SYMOFF(x) + (x).a_syms )
 120
 121 /* A single entry in the symbol table
 122  */
 123 struct nlist {
 124         union {
 125                 char    *n_name;
 126                 struct nlist *n_next;
 127                 long    n_strx;         /* Index into string table      */
 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         int      r_address;     /* File address of item to be relocated */
 153         unsigned
 154                 r_index:24,/* Index of symbol on which relocation is based*/
 155                 r_pcrel:1,      /* 1 => relocate PC-relative; else absolute
 156                                  *      On i960, pc-relative implies 24-bit
 157                                  *      address, absolute implies 32-bit.
 158                                  */
 159                 r_length:2,     /* Number of bytes to relocate:
 160                                  *      0 => 1 byte
 161                                  *      1 => 2 bytes
 162                                  *      2 => 4 bytes -- only value used for i960
 163                                  */
 164                 r_extern:1,
 165                 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 #endif /* CUSTOM_RELOC_FORMAT */
 171
 172 /* If compiler generate leading underscores, remove them. */
 173
 174 #ifndef STRIP_UNDERSCORE
 175 #define STRIP_UNDERSCORE 0
 176 #endif /* STRIP_UNDERSCORE */
 177
 178 /*
 179  *  Macros to extract information from a symbol table entry.
 180  *  This syntaxic indirection allows independence regarding a.out or coff.
 181  *  The argument (s) of all these macros is a pointer to a symbol table entry.
 182  */
 183
 184 /* Predicates */
 185 /* True if the symbol is external */
 186 #define S_IS_EXTERNAL(s)        ((s)->sy_symbol.n_type & N_EXT)
 187
 188 /* True if symbol has been defined, ie is in N_{TEXT,DATA,BSS,ABS} or N_EXT */
 189 #define S_IS_DEFINED(s)         ((S_GET_TYPE(s) != N_UNDF) || (S_GET_DESC(s) != 0))
 190 #define S_IS_REGISTER(s)        ((s)->sy_symbol.n_type == N_REGISTER)
 191
 192 /* True if a debug special symbol entry */
 193 #define S_IS_DEBUG(s)           ((s)->sy_symbol.n_type & N_STAB)
 194 /* True if a symbol is local symbol name */
 195 /* A symbol name whose name begin with ^A is a gas internal pseudo symbol
 196    nameless symbols come from .stab directives. */
 197 #define S_IS_LOCAL(s)           (S_GET_NAME(s) && \
 198                                  !S_IS_DEBUG(s) && \
 199                                  (S_GET_NAME(s)[0] == '\001' || \
 200                                   (S_LOCAL_NAME(s) && !flagseen['L'])))
 201 /* True if a symbol is not defined in this file */
 202 #define S_IS_EXTERN(s)          ((s)->sy_symbol.n_type & N_EXT)
 203 /* True if the symbol has been generated because of a .stabd directive */
 204 #define S_IS_STABD(s)           (S_GET_NAME(s) == NULL)
 205
 206 /* Accessors */
 207 /* The value of the symbol */
 208 #define S_GET_VALUE(s)          ((unsigned long) ((s)->sy_symbol.n_value))
 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 /* Set the value of the symbol */
 224 #define S_SET_VALUE(s,v)        ((s)->sy_symbol.n_value = (unsigned long) (v))
 225 /* Assume that a symbol cannot be simultaneously in more than on segment */
 226  /* set segment */
 227 #define S_SET_SEGMENT(s,seg)    ((s)->sy_symbol.n_type &= ~N_TYPE,(s)->sy_symbol.n_type|=SEGMENT_TO_SYMBOL_TYPE(seg))
 228 /* The symbol is external */
 229 #define S_SET_EXTERNAL(s)       ((s)->sy_symbol.n_type |= N_EXT)
 230 /* The symbol is not external */
 231 #define S_CLEAR_EXTERNAL(s)     ((s)->sy_symbol.n_type &= ~N_EXT)
 232 /* Set the name of the symbol */
 233 #define S_SET_NAME(s,v)         ((s)->sy_symbol.n_un.n_name = (v))
 234 /* Set the offset in the string table */
 235 #define S_SET_OFFSET(s,v)       ((s)->sy_symbol.n_un.n_strx = (v))
 236 /* Set the n_other expression value */
 237 #define S_SET_OTHER(s,v)        ((s)->sy_symbol.n_other = (v))
 238 /* Set the n_desc expression value */
 239 #define S_SET_DESC(s,v)         ((s)->sy_symbol.n_desc = (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_TEXT_SIZE(h)              ((h)->header.a_text)
 251 #define H_GET_DATA_SIZE(h)              ((h)->header.a_data)
 252 #define H_GET_BSS_SIZE(h)               ((h)->header.a_bss)
 253 #define H_GET_TEXT_RELOCATION_SIZE(h)   ((h)->header.a_trsize)
 254 #define H_GET_DATA_RELOCATION_SIZE(h)   ((h)->header.a_drsize)
 255 #define H_GET_SYMBOL_TABLE_SIZE(h)      ((h)->header.a_syms)
 256 #define H_GET_MAGIC_NUMBER(h)           ((h)->header.a_info)
 257 #define H_GET_ENTRY_POINT(h)            ((h)->header.a_entry)
 258 #define H_GET_STRING_SIZE(h)            ((h)->string_table_size)
 259 #ifdef EXEC_MACHINE_TYPE
 260 #define H_GET_MACHINE_TYPE(h)           ((h)->header.a_machtype)
 261 #endif /* EXEC_MACHINE_TYPE */
 262 #ifdef EXEC_VERSION
 263 #define H_GET_VERSION(h)                ((h)->header.a_version)
 264 #endif /* EXEC_VERSION */
 265
 266 #define H_SET_TEXT_SIZE(h,v)            ((h)->header.a_text = md_section_align(SEG_TEXT, (v)))
 267 #define H_SET_DATA_SIZE(h,v)            ((h)->header.a_data = md_section_align(SEG_DATA, (v)))
 268 #define H_SET_BSS_SIZE(h,v)             ((h)->header.a_bss = md_section_align(SEG_BSS, (v)))
 269
 270 #define H_SET_RELOCATION_SIZE(h,t,d)    (H_SET_TEXT_RELOCATION_SIZE((h),(t)),\
 271                                          H_SET_DATA_RELOCATION_SIZE((h),(d)))
 272
 273 #define H_SET_TEXT_RELOCATION_SIZE(h,v) ((h)->header.a_trsize = (v))
 274 #define H_SET_DATA_RELOCATION_SIZE(h,v) ((h)->header.a_drsize = (v))
 275 #define H_SET_SYMBOL_TABLE_SIZE(h,v)    ((h)->header.a_syms = (v) * \
 276                                          sizeof(struct nlist))
 277
 278 #define H_SET_MAGIC_NUMBER(h,v)         ((h)->header.a_magic = (v))
 279
 280 #define H_SET_ENTRY_POINT(h,v)          ((h)->header.a_entry = (v))
 281 #define H_SET_STRING_SIZE(h,v)          ((h)->string_table_size = (v))
 282 #ifdef EXEC_MACHINE_TYPE
 283 #define H_SET_MACHINE_TYPE(h,v)         ((h)->header.a_machtype = (v))
 284 #endif /* EXEC_MACHINE_TYPE */
 285 #ifdef EXEC_VERSION
 286 #define H_SET_VERSION(h,v)              ((h)->header.a_version = (v))
 287 #endif /* EXEC_VERSION */
 288
 289 /*
 290  * Current means for getting the name of a segment.
 291  * This will change for infinite-segments support (e.g. COFF).
 292  */
 293 #define segment_name(seg)  ( seg_name[(int)(seg)] )
 294 extern char *const seg_name[];
 295
 296 typedef struct {
 297     struct exec header;                 /* a.out header */
 298     long        string_table_size;      /* names + '\0' + sizeof(int) */
 299 } object_headers;
 300
 301 /* unused hooks. */
 302 #define OBJ_EMIT_LINENO(a, b, c)        ;
 303 #define obj_pre_write_hook(a)           ;
 304
 305 /*
 306  * Local Variables:
 307  * comment-column: 0
 308  * fill-column: 131
 309  * End:
 310  */
 311
 312 /* end of obj-bout.h */