1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
|
/* Copyright 1992 Free Software Foundation, Inc.
*
* This file is a modified version of 'a.out.h'. It is to be used in all
* all GNU tools modified to support the i80960 (or tools that operate on
* object files created by such tools).
*
* All i80960 development is done in a CROSS-DEVELOPMENT environment. I.e.,
* object code is generated on, and executed under the direction of a symbolic
* debugger running on, a host system. We do not want to be subject to the
* vagaries of which host it is or whether it supports COFF or a.out format,
* or anything else. We DO want to:
*
* o always generate the same format object files, regardless of host.
*
* o have an 'a.out' header that we can modify for our own purposes
* (the 80960 is typically an embedded processor and may require
* enhanced linker support that the normal a.out.h header can't
* accommodate).
*
* As for byte-ordering, the following rules apply:
*
* o Text and data that is actually downloaded to the target is always
* in i80960 (little-endian) order.
*
* o All other numbers (in the header, symbols, relocation directives)
* are in host byte-order: object files CANNOT be lifted from a
* little-end host and used on a big-endian (or vice versa) without
* modification.
*
* o The downloader ('comm960') takes care to generate a pseudo-header
* with correct (i80960) byte-ordering before shipping text and data
* off to the NINDY monitor in the target systems. Symbols and
* relocation info are never sent to the target.
*/
#define BMAGIC 0415
/* We don't accept the following (see N_BADMAG macro).
* They're just here so GNU code will compile.
*/
#define OMAGIC 0407 /* old impure format */
#define NMAGIC 0410 /* read-only text */
#define ZMAGIC 0413 /* demand load format */
/* FILE HEADER
* All 'lengths' are given as a number of bytes.
* All 'alignments' are for relinkable files only; an alignment of
* 'n' indicates the corresponding segment must begin at an
* address that is a multiple of (2**n).
*/
struct exec {
/* Standard stuff */
unsigned long a_magic; /* Identifies this as a b.out file */
unsigned long a_text; /* Length of text */
unsigned long a_data; /* Length of data */
unsigned long a_bss; /* Length of runtime uninitialized data area */
unsigned long a_syms; /* Length of symbol table */
unsigned long a_entry; /* Runtime start address */
unsigned long a_trsize; /* Length of text relocation info */
unsigned long a_drsize; /* Length of data relocation info */
/* Added for i960 */
unsigned long a_tload; /* Text runtime load address */
unsigned long a_dload; /* Data runtime load address */
unsigned char a_talign; /* Alignment of text segment */
unsigned char a_dalign; /* Alignment of data segment */
unsigned char a_balign; /* Alignment of bss segment */
unsigned char unused; /* (Just to make struct size a multiple of 4) */
};
#define N_BADMAG(x) (((x).a_magic)!=BMAGIC)
#define N_TXTOFF(x) ( sizeof(struct exec) )
#define N_DATOFF(x) ( N_TXTOFF(x) + (x).a_text )
#define N_TROFF(x) ( N_DATOFF(x) + (x).a_data )
#define N_DROFF(x) ( N_TROFF(x) + (x).a_trsize )
#define N_SYMOFF(x) ( N_DROFF(x) + (x).a_drsize )
#define N_STROFF(x) ( N_SYMOFF(x) + (x).a_syms )
/* A single entry in the symbol table
*/
struct nlist {
union {
char *n_name;
struct nlist *n_next;
long n_strx; /* Index into string table */
} n_un;
unsigned char n_type; /* See below */
char n_other; /* Used in i80960 support -- see below */
short n_desc;
unsigned long n_value;
};
/* Legal values of n_type
*/
#define N_UNDF 0 /* Undefined symbol */
#define N_ABS 2 /* Absolute symbol */
#define N_TEXT 4 /* Text symbol */
#define N_DATA 6 /* Data symbol */
#define N_BSS 8 /* BSS symbol */
#define N_FN 31 /* Filename symbol */
#define N_EXT 1 /* External symbol (OR'd in with one of above) */
#define N_TYPE 036 /* Mask for all the type bits */
#define N_STAB 0340 /* Mask for all bits used for SDB entries */
/* MEANING OF 'n_other'
*
* If non-zero, the 'n_other' fields indicates either a leaf procedure or
* a system procedure, as follows:
*
* 1 <= n_other <= 32 :
* The symbol is the entry point to a system procedure.
* 'n_value' is the address of the entry, as for any other
* procedure. The system procedure number (which can be used in
* a 'calls' instruction) is (n_other-1). These entries come from
* '.sysproc' directives.
*
* n_other == N_CALLNAME
* the symbol is the 'call' entry point to a leaf procedure.
* The *next* symbol in the symbol table must be the corresponding
* 'bal' entry point to the procedure (see following). These
* entries come from '.leafproc' directives in which two different
* symbols are specified (the first one is represented here).
*
*
* n_other == N_BALNAME
* the symbol is the 'bal' entry point to a leaf procedure.
* These entries result from '.leafproc' directives in which only
* one symbol is specified, or in which the same symbol is
* specified twice.
*
* Note that an N_CALLNAME entry *must* have a corresponding N_BALNAME entry,
* but not every N_BALNAME entry must have an N_CALLNAME entry.
*/
#define N_CALLNAME -1
#define N_BALNAME -2
struct relocation_info {
int r_address; /* File address of item to be relocated */
unsigned
r_symbolnum:24,/* Index of symbol on which relocation is based*/
r_pcrel:1, /* 1 => relocate PC-relative; else absolute
* On i960, pc-relative implies 24-bit
* address, absolute implies 32-bit.
*/
r_length:2, /* Number of bytes to relocate:
* 0 => 1 byte
* 1 => 2 bytes
* 2 => 4 bytes -- only value used for i960
*/
r_extern:1,
r_bsr:1, /* Something for the GNU NS32K assembler */
r_disp:1, /* Something for the GNU NS32K assembler */
r_callj:1, /* 1 if relocation target is an i960 'callj' */
nuthin:1; /* Unused */
};
|
