1 /* b.out object file format
2 Copyright (C) 1989, 1990, 1991, 1992 Free Software Foundation, Inc.
4 This file is part of GAS, the GNU Assembler.
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.
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.
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
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).
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:
32 * o always generate the same format object files, regardless of host.
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
39 * As for byte-ordering, the following rules apply:
41 * o Text and data that is actually downloaded to the target is always
42 * in i80960 (little-endian) order.
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
49 * o The downloader ('comm960') takes care to generate a pseudo-header
50 * with correct (i80960) byte-ordering before shipping text and data
51 * off to the NINDY monitor in the target systems. Symbols and
52 * relocation info are never sent to the target.
60 /* bout uses host byte order for headers */
63 #endif /* CROSS_COMPILE */
68 #define OBJ_DEFAULT_OUTPUT_FILE_NAME "b.out"
70 extern const short seg_N_TYPE[];
71 extern const segT N_TYPE_seg[];
74 /* We don't accept the following (see N_BADMAG macro).
75 * They're just here so GNU code will compile.
77 #define OMAGIC 0407 /* old impure format */
78 #define NMAGIC 0410 /* read-only text */
79 #define ZMAGIC 0413 /* demand load format */
82 * All 'lengths' are given as a number of bytes.
83 * All 'alignments' are for relinkable files only; an alignment of
84 * 'n' indicates the corresponding segment must begin at an
85 * address that is a multiple of (2**n).
89 unsigned long a_magic; /* Identifies this as a b.out file */
90 unsigned long a_text; /* Length of text */
91 unsigned long a_data; /* Length of data */
92 unsigned long a_bss; /* Length of runtime uninitialized data area */
93 unsigned long a_syms; /* Length of symbol table */
94 unsigned long a_entry; /* Runtime start address */
95 unsigned long a_trsize; /* Length of text relocation info */
96 unsigned long a_drsize; /* Length of data relocation info */
99 unsigned long a_tload; /* Text runtime load address */
100 unsigned long a_dload; /* Data runtime load address */
101 unsigned char a_talign; /* Alignment of text segment */
102 unsigned char a_dalign; /* Alignment of data segment */
103 unsigned char a_balign; /* Alignment of bss segment */
104 unsigned char unused; /* (Just to make struct size a multiple of 4) */
107 #define N_BADMAG(x) (((x).a_magic) != BMAGIC)
108 #define N_TXTOFF(x) ( sizeof(struct exec) )
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 )
115 /* A single entry in the symbol table
120 struct nlist *n_next;
121 long n_strx; /* Index into string table */
123 unsigned char n_type; /* See below */
124 char n_other; /* Used in i80960 support -- see below */
126 unsigned long n_value;
129 typedef struct nlist obj_symbol_type;
131 /* Legal values of n_type
133 #define N_UNDF 0 /* Undefined symbol */
134 #define N_ABS 2 /* Absolute symbol */
135 #define N_TEXT 4 /* Text symbol */
136 #define N_DATA 6 /* Data symbol */
137 #define N_BSS 8 /* BSS symbol */
138 #define N_FN 31 /* Filename symbol */
140 #define N_EXT 1 /* External symbol (OR'd in with one of above) */
141 #define N_TYPE 036 /* Mask for all the type bits */
142 #define N_STAB 0340 /* Mask for all bits used for SDB entries */
144 #ifndef CUSTOM_RELOC_FORMAT
145 struct relocation_info {
146 int r_address; /* File address of item to be relocated */
148 r_index:24,/* Index of symbol on which relocation is based*/
149 r_pcrel:1, /* 1 => relocate PC-relative; else absolute
150 * On i960, pc-relative implies 24-bit
151 * address, absolute implies 32-bit.
153 r_length:2, /* Number of bytes to relocate:
156 * 2 => 4 bytes -- only value used for i960
159 r_bsr:1, /* Something for the GNU NS32K assembler */
160 r_disp:1, /* Something for the GNU NS32K assembler */
161 r_callj:1, /* 1 if relocation target is an i960 'callj' */
162 nuthin:1; /* Unused */
164 #endif /* CUSTOM_RELOC_FORMAT */
167 * Macros to extract information from a symbol table entry.
168 * This syntaxic indirection allows independence regarding a.out or coff.
169 * The argument (s) of all these macros is a pointer to a symbol table entry.
173 /* True if the symbol is external */
174 #define S_IS_EXTERNAL(s) ((s)->sy_symbol.n_type & N_EXT)
176 /* True if symbol has been defined, ie is in N_{TEXT,DATA,BSS,ABS} or N_EXT */
177 #define S_IS_DEFINED(s) ((S_GET_TYPE(s) != N_UNDF) || (S_GET_DESC(s) != 0))
178 #define S_IS_REGISTER(s) ((s)->sy_symbol.n_type == N_REGISTER)
180 /* True if a debug special symbol entry */
181 #define S_IS_DEBUG(s) ((s)->sy_symbol.n_type & N_STAB)
182 /* True if a symbol is local symbol name */
183 /* A symbol name whose name begin with ^A is a gas internal pseudo symbol
184 nameless symbols come from .stab directives. */
185 #define S_IS_LOCAL(s) (S_GET_NAME(s) && \
187 (S_GET_NAME(s)[0] == '\001' || \
188 (S_LOCAL_NAME(s) && !flagseen['L'])))
189 /* True if a symbol is not defined in this file */
190 #define S_IS_EXTERN(s) ((s)->sy_symbol.n_type & N_EXT)
191 /* True if the symbol has been generated because of a .stabd directive */
192 #define S_IS_STABD(s) (S_GET_NAME(s) == NULL)
195 /* The value of the symbol */
196 #define S_GET_VALUE(s) ((unsigned long) ((s)->sy_symbol.n_value))
197 /* The name of the symbol */
198 #define S_GET_NAME(s) ((s)->sy_symbol.n_un.n_name)
199 /* The pointer to the string table */
200 #define S_GET_OFFSET(s) ((s)->sy_symbol.n_un.n_strx)
201 /* The type of the symbol */
202 #define S_GET_TYPE(s) ((s)->sy_symbol.n_type & N_TYPE)
203 /* The numeric value of the segment */
204 #define S_GET_SEGMENT(s) (N_TYPE_seg[S_GET_TYPE(s)])
205 /* The n_other expression value */
206 #define S_GET_OTHER(s) ((s)->sy_symbol.n_other)
207 /* The n_desc expression value */
208 #define S_GET_DESC(s) ((s)->sy_symbol.n_desc)
211 /* Set the value of the symbol */
212 #define S_SET_VALUE(s,v) ((s)->sy_symbol.n_value = (unsigned long) (v))
213 /* Assume that a symbol cannot be simultaneously in more than on segment */
215 #define S_SET_SEGMENT(s,seg) ((s)->sy_symbol.n_type &= ~N_TYPE,(s)->sy_symbol.n_type|=SEGMENT_TO_SYMBOL_TYPE(seg))
216 /* The symbol is external */
217 #define S_SET_EXTERNAL(s) ((s)->sy_symbol.n_type |= N_EXT)
218 /* The symbol is not external */
219 #define S_CLEAR_EXTERNAL(s) ((s)->sy_symbol.n_type &= ~N_EXT)
220 /* Set the name of the symbol */
221 #define S_SET_NAME(s,v) ((s)->sy_symbol.n_un.n_name = (v))
222 /* Set the offset in the string table */
223 #define S_SET_OFFSET(s,v) ((s)->sy_symbol.n_un.n_strx = (v))
224 /* Set the n_other expression value */
225 #define S_SET_OTHER(s,v) ((s)->sy_symbol.n_other = (v))
226 /* Set the n_desc expression value */
227 #define S_SET_DESC(s,v) ((s)->sy_symbol.n_desc = (v))
229 /* File header macro and type definition */
231 #define H_GET_FILE_SIZE(h) (sizeof(struct exec) + \
232 H_GET_TEXT_SIZE(h) + H_GET_DATA_SIZE(h) + \
233 H_GET_SYMBOL_TABLE_SIZE(h) + \
234 H_GET_TEXT_RELOCATION_SIZE(h) + \
235 H_GET_DATA_RELOCATION_SIZE(h) + \
236 (h)->string_table_size)
238 #define H_GET_HEADER_SIZE(h) (sizeof(struct exec))
239 #define H_GET_TEXT_SIZE(h) ((h)->header.a_text)
240 #define H_GET_DATA_SIZE(h) ((h)->header.a_data)
241 #define H_GET_BSS_SIZE(h) ((h)->header.a_bss)
242 #define H_GET_TEXT_RELOCATION_SIZE(h) ((h)->header.a_trsize)
243 #define H_GET_DATA_RELOCATION_SIZE(h) ((h)->header.a_drsize)
244 #define H_GET_SYMBOL_TABLE_SIZE(h) ((h)->header.a_syms)
245 #define H_GET_MAGIC_NUMBER(h) ((h)->header.a_info)
246 #define H_GET_ENTRY_POINT(h) ((h)->header.a_entry)
247 #define H_GET_STRING_SIZE(h) ((h)->string_table_size)
248 #define H_GET_LINENO_SIZE(h) (0)
250 #ifdef EXEC_MACHINE_TYPE
251 #define H_GET_MACHINE_TYPE(h) ((h)->header.a_machtype)
252 #endif /* EXEC_MACHINE_TYPE */
254 #define H_GET_VERSION(h) ((h)->header.a_version)
255 #endif /* EXEC_VERSION */
257 #define H_SET_TEXT_SIZE(h,v) ((h)->header.a_text = (v))
258 #define H_SET_DATA_SIZE(h,v) ((h)->header.a_data = (v))
259 #define H_SET_BSS_SIZE(h,v) ((h)->header.a_bss = (v))
261 #define H_SET_RELOCATION_SIZE(h,t,d) (H_SET_TEXT_RELOCATION_SIZE((h),(t)),\
262 H_SET_DATA_RELOCATION_SIZE((h),(d)))
264 #define H_SET_TEXT_RELOCATION_SIZE(h,v) ((h)->header.a_trsize = (v))
265 #define H_SET_DATA_RELOCATION_SIZE(h,v) ((h)->header.a_drsize = (v))
266 #define H_SET_SYMBOL_TABLE_SIZE(h,v) ((h)->header.a_syms = (v) * \
267 sizeof(struct nlist))
269 #define H_SET_MAGIC_NUMBER(h,v) ((h)->header.a_magic = (v))
271 #define H_SET_ENTRY_POINT(h,v) ((h)->header.a_entry = (v))
272 #define H_SET_STRING_SIZE(h,v) ((h)->string_table_size = (v))
273 #ifdef EXEC_MACHINE_TYPE
274 #define H_SET_MACHINE_TYPE(h,v) ((h)->header.a_machtype = (v))
275 #endif /* EXEC_MACHINE_TYPE */
277 #define H_SET_VERSION(h,v) ((h)->header.a_version = (v))
278 #endif /* EXEC_VERSION */
281 * Current means for getting the name of a segment.
282 * This will change for infinite-segments support (e.g. COFF).
284 #define segment_name(seg) ( seg_name[(int)(seg)] )
285 extern char *const seg_name[];
288 struct exec header; /* a.out header */
289 long string_table_size; /* names + '\0' + sizeof(int) */
293 #define OBJ_EMIT_LINENO(a, b, c) {;}
297 void tc_aout_fix_to_chars(char *where, struct fix *fixP, relax_addressT segment_address);
298 #else /* not __STDC__ */
299 void tc_aout_fix_to_chars();
300 #endif /* not __STDC__ */
313 /* end of obj-bout.h */