1 /* 2 * This file is a modified version of 'a.out.h'. It is to be used in all 3 * GNU tools modified to support the i80960 (or tools that operate on 4 * object files created by such tools). 5 * 6 * All i80960 development is done in a CROSS-DEVELOPMENT environment. I.e., 7 * object code is generated on, and executed under the direction of a symbolic 8 * debugger running on, a host system. We do not want to be subject to the 9 * vagaries of which host it is or whether it supports COFF or a.out format, 10 * or anything else. We DO want to: 11 * 12 * o always generate the same format object files, regardless of host. 13 * 14 * o have an 'a.out' header that we can modify for our own purposes 15 * (the 80960 is typically an embedded processor and may require 16 * enhanced linker support that the normal a.out.h header can't 17 * accommodate). 18 * 19 * As for byte-ordering, the following rules apply: 20 * 21 * o Text and data that is actually downloaded to the target is always 22 * in i80960 (little-endian) order. 23 * 24 * o All other numbers (in the header, symbols, relocation directives) 25 * are in host byte-order: object files CANNOT be lifted from a 26 * little-end host and used on a big-endian (or vice versa) without 27 * modification. 28 * ==> THIS IS NO LONGER TRUE USING BFD. WE CAN GENERATE ANY BYTE ORDER 29 * FOR THE HEADER, AND READ ANY BYTE ORDER. PREFERENCE WOULD BE TO 30 * USE LITTLE-ENDIAN BYTE ORDER THROUGHOUT, REGARDLESS OF HOST. <== 31 * 32 * o The downloader ('comm960') takes care to generate a pseudo-header 33 * with correct (i80960) byte-ordering before shipping text and data 34 * off to the NINDY monitor in the target systems. Symbols and 35 * relocation info are never sent to the target. 36 */ 37 38 39 #define BMAGIC 0415 40 /* We don't accept the following (see N_BADMAG macro). 41 * They're just here so GNU code will compile. 42 */ 43 #define OMAGIC 0407 /* old impure format */ 44 #define NMAGIC 0410 /* read-only text */ 45 #define ZMAGIC 0413 /* demand load format */ 46 47 /* FILE HEADER 48 * All 'lengths' are given as a number of bytes. 49 * All 'alignments' are for relinkable files only; an alignment of 50 * 'n' indicates the corresponding segment must begin at an 51 * address that is a multiple of (2**n). 52 */ 53 struct external_exec { 54 /* Standard stuff */ 55 unsigned char e_info[4]; /* Identifies this as a b.out file */ 56 unsigned char e_text[4]; /* Length of text */ 57 unsigned char e_data[4]; /* Length of data */ 58 unsigned char e_bss[4]; /* Length of uninitialized data area */ 59 unsigned char e_syms[4]; /* Length of symbol table */ 60 unsigned char e_entry[4]; /* Runtime start address */ 61 unsigned char e_trsize[4]; /* Length of text relocation info */ 62 unsigned char e_drsize[4]; /* Length of data relocation info */ 63 64 /* Added for i960 */ 65 unsigned char e_tload[4]; /* Text runtime load address */ 66 unsigned char e_dload[4]; /* Data runtime load address */ 67 unsigned char e_talign[1]; /* Alignment of text segment */ 68 unsigned char e_dalign[1]; /* Alignment of data segment */ 69 unsigned char e_balign[1]; /* Alignment of bss segment */ 70 unsigned char e_relaxable[1]; /* Assembled with enough info to allow linker to relax */ 71 }; 72 73 #define EXEC_BYTES_SIZE (sizeof (struct external_exec)) 74 75 /* These macros use the a_xxx field names, since they operate on the exec 76 structure after it's been byte-swapped and realigned on the host machine. */ 77 #define N_BADMAG(x) (((x).a_info)!=BMAGIC) 78 #define N_TXTOFF(x) EXEC_BYTES_SIZE 79 #define N_DATOFF(x) ( N_TXTOFF(x) + (x).a_text ) 80 #define N_TROFF(x) ( N_DATOFF(x) + (x).a_data ) 81 #define N_TRELOFF N_TROFF 82 #define N_DROFF(x) ( N_TROFF(x) + (x).a_trsize ) 83 #define N_DRELOFF N_DROFF 84 #define N_SYMOFF(x) ( N_DROFF(x) + (x).a_drsize ) 85 #define N_STROFF(x) ( N_SYMOFF(x) + (x).a_syms ) 86 #define N_DATADDR(x) ( (x).a_dload ) 87 88 /* Address of text segment in memory after it is loaded. */ 89 #if !defined (N_TXTADDR) 90 #define N_TXTADDR(x) 0 91 #endif 92 93 /* A single entry in the symbol table 94 */ 95 struct nlist { 96 union { 97 char *n_name; 98 struct nlist *n_next; 99 long n_strx; /* Index into string table */ 100 } n_un; 101 unsigned char n_type; /* See below */ 102 char n_other; /* Used in i80960 support -- see below */ 103 short n_desc; 104 unsigned long n_value; 105 }; 106 107 108 /* Legal values of n_type 109 */ 110 #define N_UNDF 0 /* Undefined symbol */ 111 #define N_ABS 2 /* Absolute symbol */ 112 #define N_TEXT 4 /* Text symbol */ 113 #define N_DATA 6 /* Data symbol */ 114 #define N_BSS 8 /* BSS symbol */ 115 #define N_FN 31 /* Filename symbol */ 116 117 #define N_EXT 1 /* External symbol (OR'd in with one of above) */ 118 #define N_TYPE 036 /* Mask for all the type bits */ 119 #define N_STAB 0340 /* Mask for all bits used for SDB entries */ 120 121 /* MEANING OF 'n_other' 122 * 123 * If non-zero, the 'n_other' fields indicates either a leaf procedure or 124 * a system procedure, as follows: 125 * 126 * 1 <= n_other <= 32 : 127 * The symbol is the entry point to a system procedure. 128 * 'n_value' is the address of the entry, as for any other 129 * procedure. The system procedure number (which can be used in 130 * a 'calls' instruction) is (n_other-1). These entries come from 131 * '.sysproc' directives. 132 * 133 * n_other == N_CALLNAME 134 * the symbol is the 'call' entry point to a leaf procedure. 135 * The *next* symbol in the symbol table must be the corresponding 136 * 'bal' entry point to the procedure (see following). These 137 * entries come from '.leafproc' directives in which two different 138 * symbols are specified (the first one is represented here). 139 * 140 * 141 * n_other == N_BALNAME 142 * the symbol is the 'bal' entry point to a leaf procedure. 143 * These entries result from '.leafproc' directives in which only 144 * one symbol is specified, or in which the same symbol is 145 * specified twice. 146 * 147 * Note that an N_CALLNAME entry *must* have a corresponding N_BALNAME entry, 148 * but not every N_BALNAME entry must have an N_CALLNAME entry. 149 */ 150 #define N_CALLNAME ((char)-1) 151 #define N_BALNAME ((char)-2) 152 #define IS_CALLNAME(x) (N_CALLNAME == (x)) 153 #define IS_BALNAME(x) (N_BALNAME == (x)) 154 #define IS_OTHER(x) ((x)>0 && (x) <=32) 155 156 #define b_out_relocation_info relocation_info 157 struct relocation_info { 158 int r_address; /* File address of item to be relocated */ 159 unsigned 160 #define r_index r_symbolnum 161 r_symbolnum:24,/* Index of symbol on which relocation is based, 162 * if r_extern is set. Otherwise set to 163 * either N_TEXT, N_DATA, or N_BSS to 164 * indicate section on which relocation is 165 * based. 166 */ 167 r_pcrel:1, /* 1 => relocate PC-relative; else absolute 168 * On i960, pc-relative implies 24-bit 169 * address, absolute implies 32-bit. 170 */ 171 r_length:2, /* Number of bytes to relocate: 172 * 0 => 1 byte 173 * 1 => 2 bytes -- used for 13 bit pcrel 174 * 2 => 4 bytes 175 */ 176 r_extern:1, 177 r_bsr:1, /* Something for the GNU NS32K assembler */ 178 r_disp:1, /* Something for the GNU NS32K assembler */ 179 r_callj:1, /* 1 if relocation target is an i960 'callj' */ 180 r_relaxable:1; /* 1 if enough info is left to relax 181 the data */ 182 }; 183