1 /* b.out object file format 2 Copyright 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 2000, 3 2002, 2003, 2005 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, 51 Franklin Street - Fifth Floor, Cambridge, MA 20 02139, USA. */ 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 #define OBJ_BOUT 1 58 59 #define OUTPUT_FLAVOR bfd_target_aout_flavour 60 61 #include "targ-cpu.h" 62 63 #define OBJ_DEFAULT_OUTPUT_FILE_NAME "b.out" 64 65 extern const short seg_N_TYPE[]; 66 extern const segT N_TYPE_seg[]; 67 68 #define BMAGIC 0415 69 /* We don't accept the following (see N_BADMAG macro). 70 They're just here so GNU code will compile. */ 71 #define OMAGIC 0407 /* Old impure format. */ 72 #define NMAGIC 0410 /* Read-only text. */ 73 #define ZMAGIC 0413 /* Demand load format. */ 74 75 #ifndef DEFAULT_MAGIC_NUMBER_FOR_OBJECT_FILE 76 #define DEFAULT_MAGIC_NUMBER_FOR_OBJECT_FILE BMAGIC 77 #endif 78 79 /* File header: 80 All 'lengths' are given as a number of bytes. 81 All 'alignments' are for relinkable files only; an alignment of 82 'n' indicates the corresponding segment must begin at an 83 address that is a multiple of (2**n). */ 84 struct exec 85 { 86 /* Standard stuff. */ 87 unsigned long a_magic; /* Identifies this as a b.out file. */ 88 unsigned long a_text; /* Length of text. */ 89 unsigned long a_data; /* Length of data. */ 90 unsigned long a_bss; /* Length of runtime uninitialized data area. */ 91 unsigned long a_syms; /* Length of symbol table. */ 92 unsigned long a_entry; /* Runtime start address. */ 93 unsigned long a_trsize; /* Length of text relocation info. */ 94 unsigned long a_drsize; /* Length of data relocation info. */ 95 96 /* Added for i960 */ 97 unsigned long a_tload; /* Text runtime load address. */ 98 unsigned long a_dload; /* Data runtime load address. */ 99 unsigned char a_talign; /* Alignment of text segment. */ 100 unsigned char a_dalign; /* Alignment of data segment. */ 101 unsigned char a_balign; /* Alignment of bss segment. */ 102 unsigned char a_relaxable; /* Contains enough info to relax. */ 103 }; 104 105 #define EXEC_BYTES_SIZE (10 * 4 + 4 * 1) 106 107 #define N_BADMAG(x) (((x).a_magic) != BMAGIC) 108 #define N_TXTOFF(x) EXEC_BYTES_SIZE 109 #define N_DATOFF(x) ( N_TXTOFF(x) + (x).a_text ) 110 #define N_TROFF(x) ( N_DATOFF(x) + (x).a_data ) 111 #define N_DROFF(x) ( N_TROFF(x) + (x).a_trsize ) 112 #define N_SYMOFF(x) ( N_DROFF(x) + (x).a_drsize ) 113 #define N_STROFF(x) ( N_SYMOFF(x) + (x).a_syms ) 114 115 /* A single entry in the symbol table. */ 116 struct nlist 117 { 118 union 119 { 120 char *n_name; 121 struct nlist *n_next; 122 long n_strx; /* Index into string table. */ 123 } 124 n_un; 125 unsigned char n_type; /* See below. */ 126 char n_other; /* Used in i80960 support -- see below. */ 127 short n_desc; 128 unsigned long n_value; 129 }; 130 131 typedef struct nlist obj_symbol_type; 132 133 /* Legal values of n_type. */ 134 #define N_UNDF 0 /* Undefined symbol. */ 135 #define N_ABS 2 /* Absolute symbol. */ 136 #define N_TEXT 4 /* Text symbol. */ 137 #define N_DATA 6 /* Data symbol. */ 138 #define N_BSS 8 /* BSS symbol. */ 139 #define N_FN 31 /* Filename symbol. */ 140 141 #define N_EXT 1 /* External symbol (OR'd in with one of above). */ 142 #define N_TYPE 036 /* Mask for all the type bits. */ 143 #define N_STAB 0340 /* Mask for all bits used for SDB entries. */ 144 145 #ifndef CUSTOM_RELOC_FORMAT 146 struct relocation_info 147 { 148 int r_address; /* File address of item to be relocated. */ 149 unsigned 150 r_index:24, /* Index of symbol on which relocation is based. */ 151 r_pcrel:1, /* 1 => relocate PC-relative; else absolute 152 On i960, pc-relative implies 24-bit 153 address, absolute implies 32-bit. */ 154 r_length:2, /* Number of bytes to relocate: 155 0 => 1 byte 156 1 => 2 bytes 157 2 => 4 bytes -- only value used for i960. */ 158 r_extern:1, r_bsr:1, /* Something for the GNU NS32K assembler. */ 159 r_disp:1, /* Something for the GNU NS32K assembler. */ 160 r_callj:1, /* 1 if relocation target is an i960 'callj'. */ 161 nuthin:1; /* Unused. */ 162 }; 163 164 #endif /* CUSTOM_RELOC_FORMAT */ 165 166 /* Macros to extract information from a symbol table entry. 167 This syntactic indirection allows independence regarding a.out or coff. 168 The argument (s) of all these macros is a pointer to a symbol table entry. */ 169 170 /* Predicates. */ 171 /* True if the symbol is external. */ 172 #define S_IS_EXTERNAL(s) ((s)->sy_symbol.n_type & N_EXT) 173 174 /* True if symbol has been defined, ie is in N_{TEXT,DATA,BSS,ABS} or N_EXT. */ 175 #define S_IS_DEFINED(s) ((S_GET_TYPE(s) != N_UNDF) || (S_GET_DESC(s) != 0)) 176 177 /* Return true for symbols that should not be reduced to section 178 symbols or eliminated from expressions, because they may be 179 overridden by the linker. */ 180 #define S_FORCE_RELOC(s, strict) \ 181 (!SEG_NORMAL (S_GET_SEGMENT (s))) 182 183 #define S_IS_COMMON(s) \ 184 (S_GET_TYPE (s) == N_UNDF && S_GET_VALUE (s) != 0) 185 186 #define S_IS_REGISTER(s) ((s)->sy_symbol.n_type == N_REGISTER) 187 188 /* True if a debug special symbol entry. */ 189 #define S_IS_DEBUG(s) ((s)->sy_symbol.n_type & N_STAB) 190 /* True if a symbol is local symbol name. */ 191 #define S_IS_LOCAL(s) \ 192 ((S_GET_NAME (s) \ 193 && !S_IS_DEBUG (s) \ 194 && (strchr (S_GET_NAME (s), '\001') != NULL \ 195 || strchr (S_GET_NAME (s), '\002') != NULL \ 196 || (S_LOCAL_NAME(s) && !flag_keep_locals))) \ 197 || (flag_strip_local_absolute \ 198 && !S_IS_EXTERNAL(s) \ 199 && S_GET_SEGMENT(s) == absolute_section)) 200 /* True if the symbol has been generated because of a .stabd directive. */ 201 #define S_IS_STABD(s) (S_GET_NAME(s) == NULL) 202 203 /* Accessors. */ 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 /* Assume that a symbol cannot be simultaneously in more than on segment. */ 219 /* Set segment. */ 220 #define S_SET_SEGMENT(s,seg) ((s)->sy_symbol.n_type &= ~N_TYPE,(s)->sy_symbol.n_type |= SEGMENT_TO_SYMBOL_TYPE (seg)) 221 /* The symbol is external. */ 222 #define S_SET_EXTERNAL(s) ((s)->sy_symbol.n_type |= N_EXT) 223 /* The symbol is not external. */ 224 #define S_CLEAR_EXTERNAL(s) ((s)->sy_symbol.n_type &= ~N_EXT) 225 /* Set the name of the symbol. */ 226 #define S_SET_NAME(s,v) ((s)->sy_symbol.n_un.n_name = (v)) 227 /* Set the offset in the string table. */ 228 #define S_SET_OFFSET(s,v) ((s)->sy_symbol.n_un.n_strx = (v)) 229 /* Set the n_other expression value. */ 230 #define S_SET_OTHER(s,v) ((s)->sy_symbol.n_other = (v)) 231 /* Set the n_desc expression value. */ 232 #define S_SET_DESC(s,v) ((s)->sy_symbol.n_desc = (v)) 233 /* Set the n_type value. */ 234 #define S_SET_TYPE(s,v) ((s)->sy_symbol.n_type = (v)) 235 236 /* File header macro and type definition. */ 237 238 #define H_GET_FILE_SIZE(h) (EXEC_BYTES_SIZE \ 239 + H_GET_TEXT_SIZE (h) \ 240 + H_GET_DATA_SIZE(h) \ 241 + H_GET_SYMBOL_TABLE_SIZE (h) \ 242 + H_GET_TEXT_RELOCATION_SIZE (h) \ 243 + H_GET_DATA_RELOCATION_SIZE (h) \ 244 + (h)->string_table_size) 245 246 #define H_GET_HEADER_SIZE(h) EXEC_BYTES_SIZE 247 #define H_GET_TEXT_SIZE(h) ((h)->header.a_text) 248 #define H_GET_DATA_SIZE(h) ((h)->header.a_data) 249 #define H_GET_BSS_SIZE(h) ((h)->header.a_bss) 250 #define H_GET_TEXT_RELOCATION_SIZE(h) ((h)->header.a_trsize) 251 #define H_GET_DATA_RELOCATION_SIZE(h) ((h)->header.a_drsize) 252 #define H_GET_SYMBOL_TABLE_SIZE(h) ((h)->header.a_syms) 253 #define H_GET_MAGIC_NUMBER(h) ((h)->header.a_info) 254 #define H_GET_ENTRY_POINT(h) ((h)->header.a_entry) 255 #define H_GET_STRING_SIZE(h) ((h)->string_table_size) 256 #define H_GET_LINENO_SIZE(h) (0) 257 258 #ifdef EXEC_MACHINE_TYPE 259 #define H_GET_MACHINE_TYPE(h) ((h)->header.a_machtype) 260 #endif /* EXEC_MACHINE_TYPE. */ 261 #ifdef EXEC_VERSION 262 #define H_GET_VERSION(h) ((h)->header.a_version) 263 #endif /* EXEC_VERSION. */ 264 265 #define H_SET_TEXT_SIZE(h,v) ((h)->header.a_text = (v)) 266 #define H_SET_DATA_SIZE(h,v) ((h)->header.a_data = (v)) 267 #define H_SET_BSS_SIZE(h,v) ((h)->header.a_bss = (v)) 268 269 #define H_SET_RELOCATION_SIZE(h,t,d) (H_SET_TEXT_RELOCATION_SIZE((h),(t)),\ 270 H_SET_DATA_RELOCATION_SIZE((h),(d))) 271 272 #define H_SET_TEXT_RELOCATION_SIZE(h,v) ((h)->header.a_trsize = (v)) 273 #define H_SET_DATA_RELOCATION_SIZE(h,v) ((h)->header.a_drsize = (v)) 274 #define H_SET_SYMBOL_TABLE_SIZE(h,v) ((h)->header.a_syms = (v) * 12) 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 typedef struct 288 { 289 struct exec header; /* a.out header. */ 290 long string_table_size; /* names + '\0' + sizeof (int). */ 291 } 292 293 object_headers; 294 295 /* Unused hooks. */ 296 #define OBJ_EMIT_LINENO(a, b, c) {;} 297 #define obj_pre_write_hook(a) {;} 298 299 #if WORDS_BIGENDIAN 300 #define host_number_to_chars number_to_chars_bigendian 301 #else 302 #define host_number_to_chars number_to_chars_littleendian 303 #endif 304 305 struct fix; 306 307 extern void tc_aout_fix_to_chars (char *, struct fix *, relax_addressT); 308 extern void tc_bout_fix_to_chars (char *, struct fix *, relax_addressT); 309 310 #define AOUT_STABS 311