source: trunk/libs/newlib/src/include/aout/encap.h

Last change on this file was 444, checked in by satin@…, 6 years ago

add newlib,libalmos-mkh, restructure shared_syscalls.h and mini-libc

File size: 4.6 KB
Line 
1/* Yet Another Try at encapsulating bfd object files in coff.
2   Copyright 1988, 1989, 1991, 2010 Free Software Foundation, Inc.
3   Written by Pace Willisson 12/9/88
4
5   This file is obsolete.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
7
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.
12
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.
17
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.  */
22
23/*
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.
29 *
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.
35 *
36 * The only problem is to track down the bsd exec header.  The
37 * macros HEADER_OFFSET, etc do this.
38 */
39
40#define N_FLAGS_COFF_ENCAPSULATE 0x20 /* coff header precedes bsd header */
41
42/* Describe the COFF header used for encapsulation.  */
43
44struct coffheader
45{
46  /* filehdr */
47  unsigned short f_magic;
48  unsigned short f_nscns;
49  long f_timdat;
50  long f_symptr;
51  long f_nsyms;
52  unsigned short f_opthdr;
53  unsigned short f_flags;
54  /* aouthdr */
55  short magic;
56  short vstamp;
57  long tsize;
58  long dsize;
59  long bsize;
60  long entry;
61  long text_start;
62  long data_start;
63  struct coffscn
64    {
65      char s_name[8];
66      long s_paddr;
67      long s_vaddr;
68      long s_size;
69      long s_scnptr;
70      long s_relptr;
71      long s_lnnoptr;
72      unsigned short s_nreloc;
73      unsigned short s_nlnno;
74      long s_flags;
75    } scns[3];
76};
77
78/* Describe some of the parameters of the encapsulation,
79   including how to find the encapsulated BSD header.  */
80
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.  */
86   
87#define COFF_MAGIC_I386 0514 /* I386MAGIC */
88#define COFF_MAGIC_M68K 0520 /* MC68MAGIC */
89
90#ifdef COFF_MAGIC
91short __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)
97#else
98#define HEADER_OFFSET(f) 0
99#endif
100
101#define HEADER_SEEK(f) (fseek ((f), HEADER_OFFSET((f)), 1))
102
103/* Describe the characteristics of the BSD header
104   that appears inside the encapsulation.  */
105
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.
110
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.
115
116   The _N_HDROFF gets sizeof struct exec added to it, so we have
117   to compensate here.  See <a.out.gnu.h>.  */
118
119#undef _N_HDROFF
120#undef N_TXTADDR
121#undef N_DATADDR
122
123#define _N_HDROFF(x) ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \
124                      sizeof (struct coffheader) : 0)
125
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
131
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))
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