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c906108c SS |
1 | /* Copyright 1992 Free Software Foundation, Inc. |
2 | * | |
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). | |
6 | * | |
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: | |
12 | * | |
13 | * o always generate the same format object files, regardless of host. | |
14 | * | |
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 | |
18 | * accommodate). | |
19 | * | |
20 | * As for byte-ordering, the following rules apply: | |
21 | * | |
22 | * o Text and data that is actually downloaded to the target is always | |
23 | * in i80960 (little-endian) order. | |
24 | * | |
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 | |
28 | * modification. | |
29 | * | |
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. | |
34 | */ | |
35 | ||
36 | ||
37 | #define BMAGIC 0415 | |
38 | /* We don't accept the following (see N_BADMAG macro). | |
39 | * They're just here so GNU code will compile. | |
40 | */ | |
41 | #define OMAGIC 0407 /* old impure format */ | |
42 | #define NMAGIC 0410 /* read-only text */ | |
43 | #define ZMAGIC 0413 /* demand load format */ | |
44 | ||
45 | /* FILE HEADER | |
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). | |
50 | */ | |
51 | struct exec { | |
52 | /* Standard stuff */ | |
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 */ | |
61 | ||
62 | /* Added for i960 */ | |
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) */ | |
69 | }; | |
70 | ||
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 ) | |
78 | ||
79 | /* A single entry in the symbol table | |
80 | */ | |
81 | struct nlist { | |
82 | union { | |
83 | char *n_name; | |
84 | struct nlist *n_next; | |
85 | long n_strx; /* Index into string table */ | |
86 | } n_un; | |
87 | unsigned char n_type; /* See below */ | |
88 | char n_other; /* Used in i80960 support -- see below */ | |
89 | short n_desc; | |
90 | unsigned long n_value; | |
91 | }; | |
92 | ||
93 | ||
94 | /* Legal values of n_type | |
95 | */ | |
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 */ | |
102 | ||
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 */ | |
106 | ||
107 | /* MEANING OF 'n_other' | |
108 | * | |
109 | * If non-zero, the 'n_other' fields indicates either a leaf procedure or | |
110 | * a system procedure, as follows: | |
111 | * | |
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. | |
118 | * | |
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). | |
125 | * | |
126 | * | |
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 | |
131 | * specified twice. | |
132 | * | |
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. | |
135 | */ | |
136 | #define N_CALLNAME -1 | |
137 | #define N_BALNAME -2 | |
138 | ||
139 | ||
140 | struct relocation_info { | |
141 | int r_address; /* File address of item to be relocated */ | |
142 | unsigned | |
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. | |
147 | */ | |
148 | r_length:2, /* Number of bytes to relocate: | |
149 | * 0 => 1 byte | |
150 | * 1 => 2 bytes | |
151 | * 2 => 4 bytes -- only value used for i960 | |
152 | */ | |
153 | r_extern:1, | |
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 */ | |
158 | }; |