1 /* Yet Another Try at encapsulating bfd object files in coff.
2 Copyright (C) 1988-2020 Free Software Foundation, Inc.
3 Written by Pace Willisson 12/9/88
5 This file is obsolete. It needs to be converted to just define a bunch
6 of stuff that BFD can use to do coff-encapsulated files. --gnu@cygnus.com
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 MA 02110-1301, USA. */
24 * We only use the coff headers to tell the kernel
25 * how to exec the file. Therefore, the only fields that need to
26 * be filled in are the scnptr and vaddr for the text and data
27 * sections, and the vaddr for the bss. As far as coff is concerned,
28 * there is no symbol table, relocation, or line numbers.
30 * A normal bsd header (struct exec) is placed after the coff headers,
31 * and before the real text. I defined a the new fields 'a_machtype'
32 * and a_flags. If a_machtype is M_386, and a_flags & A_ENCAP is
33 * true, then the bsd header is preceeded by a coff header. Macros
34 * like N_TXTOFF and N_TXTADDR use this field to find the bsd header.
36 * The only problem is to track down the bsd exec header. The
37 * macros HEADER_OFFSET, etc do this.
40 #define N_FLAGS_COFF_ENCAPSULATE 0x20 /* coff header precedes bsd header */
42 /* Describe the COFF header used for encapsulation. */
47 unsigned short f_magic
;
48 unsigned short f_nscns
;
52 unsigned short f_opthdr
;
53 unsigned short f_flags
;
72 unsigned short s_nreloc
;
73 unsigned short s_nlnno
;
78 /* Describe some of the parameters of the encapsulation,
79 including how to find the encapsulated BSD header. */
81 /* FIXME, this is dumb. The same tools can't handle a.outs for different
82 architectures, just because COFF_MAGIC is different; so you need a
83 separate GNU nm for every architecture!!? Unfortunately, it needs to
84 be this way, since the COFF_MAGIC value is determined by the kernel
85 we're trying to fool here. */
87 #define COFF_MAGIC_I386 0514 /* I386MAGIC */
88 #define COFF_MAGIC_M68K 0520 /* MC68MAGIC */
91 short __header_offset_temp
;
92 #define HEADER_OFFSET(f) \
93 (__header_offset_temp = 0, \
94 fread ((char *)&__header_offset_temp, sizeof (short), 1, (f)), \
95 fseek ((f), -sizeof (short), 1), \
96 __header_offset_temp==COFF_MAGIC ? sizeof(struct coffheader) : 0)
98 #define HEADER_OFFSET(f) 0
101 #define HEADER_SEEK(f) (fseek ((f), HEADER_OFFSET((f)), 1))
103 /* Describe the characteristics of the BSD header
104 that appears inside the encapsulation. */
106 /* Encapsulated coff files that are linked ZMAGIC have a text segment
107 offset just past the header (and a matching TXTADDR), excluding
108 the headers from the text segment proper but keeping the physical
109 layout and the virtual memory layout page-aligned.
111 Non-encapsulated a.out files that are linked ZMAGIC have a text
112 segment that starts at 0 and an N_TXTADR similarly offset to 0.
113 They too are page-aligned with each other, but they include the
114 a.out header as part of the text.
116 The _N_HDROFF gets sizeof struct exec added to it, so we have
117 to compensate here. See <a.out.gnu.h>. */
123 #define _N_HDROFF(x) ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \
124 sizeof (struct coffheader) : 0)
126 /* Address of text segment in memory after it is loaded. */
127 #define N_TXTADDR(x) \
128 ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \
129 sizeof (struct coffheader) + sizeof (struct exec) : 0)
130 #define SEGMENT_SIZE 0x400000
132 #define N_DATADDR(x) \
133 ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \
134 (SEGMENT_SIZE + ((N_TXTADDR(x)+(x)->a_text-1) & ~(SEGMENT_SIZE-1))) : \
135 (N_TXTADDR(x)+(x)->a_text))