1 /* Copyright 1992 Free Software Foundation, Inc.
3 * This file is a modified version of 'a.out.h'. It is to be used in all
4 * all GNU tools modified to support the i80960 (or tools that operate on
5 * object files created by such tools).
7 * All i80960 development is done in a CROSS-DEVELOPMENT environment. I.e.,
8 * object code is generated on, and executed under the direction of a symbolic
9 * debugger running on, a host system. We do not want to be subject to the
10 * vagaries of which host it is or whether it supports COFF or a.out format,
11 * or anything else. We DO want to:
13 * o always generate the same format object files, regardless of host.
15 * o have an 'a.out' header that we can modify for our own purposes
16 * (the 80960 is typically an embedded processor and may require
17 * enhanced linker support that the normal a.out.h header can't
20 * As for byte-ordering, the following rules apply:
22 * o Text and data that is actually downloaded to the target is always
23 * in i80960 (little-endian) order.
25 * o All other numbers (in the header, symbols, relocation directives)
26 * are in host byte-order: object files CANNOT be lifted from a
27 * little-end host and used on a big-endian (or vice versa) without
30 * o The downloader ('comm960') takes care to generate a pseudo-header
31 * with correct (i80960) byte-ordering before shipping text and data
32 * off to the NINDY monitor in the target systems. Symbols and
33 * relocation info are never sent to the target.
38 /* We don't accept the following (see N_BADMAG macro).
39 * They're just here so GNU code will compile.
41 #define OMAGIC 0407 /* old impure format */
42 #define NMAGIC 0410 /* read-only text */
43 #define ZMAGIC 0413 /* demand load format */
46 * All 'lengths' are given as a number of bytes.
47 * All 'alignments' are for relinkable files only; an alignment of
48 * 'n' indicates the corresponding segment must begin at an
49 * address that is a multiple of (2**n).
53 unsigned long a_magic
; /* Identifies this as a b.out file */
54 unsigned long a_text
; /* Length of text */
55 unsigned long a_data
; /* Length of data */
56 unsigned long a_bss
; /* Length of runtime uninitialized data area */
57 unsigned long a_syms
; /* Length of symbol table */
58 unsigned long a_entry
; /* Runtime start address */
59 unsigned long a_trsize
; /* Length of text relocation info */
60 unsigned long a_drsize
; /* Length of data relocation info */
63 unsigned long a_tload
; /* Text runtime load address */
64 unsigned long a_dload
; /* Data runtime load address */
65 unsigned char a_talign
; /* Alignment of text segment */
66 unsigned char a_dalign
; /* Alignment of data segment */
67 unsigned char a_balign
; /* Alignment of bss segment */
68 unsigned char unused
; /* (Just to make struct size a multiple of 4) */
71 #define N_BADMAG(x) (((x).a_magic)!=BMAGIC)
72 #define N_TXTOFF(x) ( sizeof(struct exec) )
73 #define N_DATOFF(x) ( N_TXTOFF(x) + (x).a_text )
74 #define N_TROFF(x) ( N_DATOFF(x) + (x).a_data )
75 #define N_DROFF(x) ( N_TROFF(x) + (x).a_trsize )
76 #define N_SYMOFF(x) ( N_DROFF(x) + (x).a_drsize )
77 #define N_STROFF(x) ( N_SYMOFF(x) + (x).a_syms )
79 /* A single entry in the symbol table
85 long n_strx
; /* Index into string table */
87 unsigned char n_type
; /* See below */
88 char n_other
; /* Used in i80960 support -- see below */
90 unsigned long n_value
;
94 /* Legal values of n_type
96 #define N_UNDF 0 /* Undefined symbol */
97 #define N_ABS 2 /* Absolute symbol */
98 #define N_TEXT 4 /* Text symbol */
99 #define N_DATA 6 /* Data symbol */
100 #define N_BSS 8 /* BSS symbol */
101 #define N_FN 31 /* Filename symbol */
103 #define N_EXT 1 /* External symbol (OR'd in with one of above) */
104 #define N_TYPE 036 /* Mask for all the type bits */
105 #define N_STAB 0340 /* Mask for all bits used for SDB entries */
107 /* MEANING OF 'n_other'
109 * If non-zero, the 'n_other' fields indicates either a leaf procedure or
110 * a system procedure, as follows:
112 * 1 <= n_other <= 32 :
113 * The symbol is the entry point to a system procedure.
114 * 'n_value' is the address of the entry, as for any other
115 * procedure. The system procedure number (which can be used in
116 * a 'calls' instruction) is (n_other-1). These entries come from
117 * '.sysproc' directives.
119 * n_other == N_CALLNAME
120 * the symbol is the 'call' entry point to a leaf procedure.
121 * The *next* symbol in the symbol table must be the corresponding
122 * 'bal' entry point to the procedure (see following). These
123 * entries come from '.leafproc' directives in which two different
124 * symbols are specified (the first one is represented here).
127 * n_other == N_BALNAME
128 * the symbol is the 'bal' entry point to a leaf procedure.
129 * These entries result from '.leafproc' directives in which only
130 * one symbol is specified, or in which the same symbol is
133 * Note that an N_CALLNAME entry *must* have a corresponding N_BALNAME entry,
134 * but not every N_BALNAME entry must have an N_CALLNAME entry.
136 #define N_CALLNAME -1
140 struct relocation_info
{
141 int r_address
; /* File address of item to be relocated */
143 r_symbolnum
:24,/* Index of symbol on which relocation is based*/
144 r_pcrel
:1, /* 1 => relocate PC-relative; else absolute
145 * On i960, pc-relative implies 24-bit
146 * address, absolute implies 32-bit.
148 r_length
:2, /* Number of bytes to relocate:
151 * 2 => 4 bytes -- only value used for i960
154 r_bsr
:1, /* Something for the GNU NS32K assembler */
155 r_disp
:1, /* Something for the GNU NS32K assembler */
156 r_callj
:1, /* 1 if relocation target is an i960 'callj' */
157 nuthin
:1; /* Unused */
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