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authorSteve Chamberlain <sac@cygnus>1991-12-01 02:29:45 +0000
committerSteve Chamberlain <sac@cygnus>1991-12-01 02:29:45 +0000
commit0227e9187ba62196cafdb14b5306d93e5cf3ed00 (patch)
tree5e2b8aa5903dfff07a9d2ee193d8355afa2d8e66 /include/aout/encap.h
parent1484208fc1a0a87506abf0b17fb5e7b929dbfb26 (diff)
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+/* Yet Another Try at encapsulating bsd object files in coff.
+ Copyright (C) 1988, 1989, 1991 Free Software Foundation, Inc.
+ Written by Pace Willisson 12/9/88
+
+ This file is obsolete. It needs to be converted to just define a bunch
+ of stuff that BFD can use to do coff-encapsulated files. --gnu@cygnus.com
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+/*
+ * We only use the coff headers to tell the kernel
+ * how to exec the file. Therefore, the only fields that need to
+ * be filled in are the scnptr and vaddr for the text and data
+ * sections, and the vaddr for the bss. As far as coff is concerned,
+ * there is no symbol table, relocation, or line numbers.
+ *
+ * A normal bsd header (struct exec) is placed after the coff headers,
+ * and before the real text. I defined a the new fields 'a_machtype'
+ * and a_flags. If a_machtype is M_386, and a_flags & A_ENCAP is
+ * true, then the bsd header is preceeded by a coff header. Macros
+ * like N_TXTOFF and N_TXTADDR use this field to find the bsd header.
+ *
+ * The only problem is to track down the bsd exec header. The
+ * macros HEADER_OFFSET, etc do this.
+ */
+
+#define N_FLAGS_COFF_ENCAPSULATE 0x20 /* coff header precedes bsd header */
+
+/* Describe the COFF header used for encapsulation. */
+
+struct coffheader
+{
+ /* filehdr */
+ unsigned short f_magic;
+ unsigned short f_nscns;
+ long f_timdat;
+ long f_symptr;
+ long f_nsyms;
+ unsigned short f_opthdr;
+ unsigned short f_flags;
+ /* aouthdr */
+ short magic;
+ short vstamp;
+ long tsize;
+ long dsize;
+ long bsize;
+ long entry;
+ long text_start;
+ long data_start;
+ struct coffscn
+ {
+ char s_name[8];
+ long s_paddr;
+ long s_vaddr;
+ long s_size;
+ long s_scnptr;
+ long s_relptr;
+ long s_lnnoptr;
+ unsigned short s_nreloc;
+ unsigned short s_nlnno;
+ long s_flags;
+ } scns[3];
+};
+
+/* Describe some of the parameters of the encapsulation,
+ including how to find the encapsulated BSD header. */
+
+/* FIXME, this is dumb. The same tools can't handle a.outs for different
+ architectures, just because COFF_MAGIC is different; so you need a
+ separate GNU nm for every architecture!!? Unfortunately, it needs to
+ be this way, since the COFF_MAGIC value is determined by the kernel
+ we're trying to fool here. */
+
+#define COFF_MAGIC_I386 0514 /* I386MAGIC */
+#define COFF_MAGIC_M68K 0520 /* MC68MAGIC */
+#define COFF_MAGIC_A29K 0x17A /* Used by asm29k cross-tools */
+
+#ifdef COFF_MAGIC
+short __header_offset_temp;
+#define HEADER_OFFSET(f) \
+ (__header_offset_temp = 0, \
+ fread ((char *)&__header_offset_temp, sizeof (short), 1, (f)), \
+ fseek ((f), -sizeof (short), 1), \
+ __header_offset_temp==COFF_MAGIC ? sizeof(struct coffheader) : 0)
+#else
+#define HEADER_OFFSET(f) 0
+#endif
+
+#define HEADER_SEEK(f) (fseek ((f), HEADER_OFFSET((f)), 1))
+
+/* Describe the characteristics of the BSD header
+ that appears inside the encapsulation. */
+
+/* Encapsulated coff files that are linked ZMAGIC have a text segment
+ offset just past the header (and a matching TXTADDR), excluding
+ the headers from the text segment proper but keeping the physical
+ layout and the virtual memory layout page-aligned.
+
+ Non-encapsulated a.out files that are linked ZMAGIC have a text
+ segment that starts at 0 and an N_TXTADR similarly offset to 0.
+ They too are page-aligned with each other, but they include the
+ a.out header as part of the text.
+
+ The _N_HDROFF gets sizeof struct exec added to it, so we have
+ to compensate here. See <a.out.gnu.h>. */
+
+#undef _N_HDROFF
+#undef N_TXTADDR
+#undef N_DATADDR
+
+#define _N_HDROFF(x) ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \
+ sizeof (struct coffheader) : 0)
+
+/* Address of text segment in memory after it is loaded. */
+#define N_TXTADDR(x) \
+ ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \
+ sizeof (struct coffheader) + sizeof (struct exec) : 0)
+#define SEGMENT_SIZE 0x400000
+
+#define N_DATADDR(x) \
+ ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \
+ (SEGMENT_SIZE + ((N_TXTADDR(x)+(x).a_text-1) & ~(SEGMENT_SIZE-1))) : \
+ (N_TXTADDR(x)+(x).a_text))