00001 /* This file is a modified version of 'a.out.h'. It is to be used in all 00002 GNU tools modified to support the i80960 (or tools that operate on 00003 object files created by such tools). 00004 00005 Copyright 2001 Free Software Foundation, Inc. 00006 00007 This program is free software; you can redistribute it and/or modify 00008 it under the terms of the GNU General Public License as published by 00009 the Free Software Foundation; either version 2 of the License, or 00010 (at your option) any later version. 00011 00012 This program is distributed in the hope that it will be useful, 00013 but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00015 GNU General Public License for more details. 00016 00017 You should have received a copy of the GNU General Public License 00018 along with this program; if not, write to the Free Software 00019 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ 00020 00021 /* All i80960 development is done in a CROSS-DEVELOPMENT environment. I.e., 00022 object code is generated on, and executed under the direction of a symbolic 00023 debugger running on, a host system. We do not want to be subject to the 00024 vagaries of which host it is or whether it supports COFF or a.out format, 00025 or anything else. We DO want to: 00026 00027 o always generate the same format object files, regardless of host. 00028 00029 o have an 'a.out' header that we can modify for our own purposes 00030 (the 80960 is typically an embedded processor and may require 00031 enhanced linker support that the normal a.out.h header can't 00032 accommodate). 00033 00034 As for byte-ordering, the following rules apply: 00035 00036 o Text and data that is actually downloaded to the target is always 00037 in i80960 (little-endian) order. 00038 00039 o All other numbers (in the header, symbols, relocation directives) 00040 are in host byte-order: object files CANNOT be lifted from a 00041 little-end host and used on a big-endian (or vice versa) without 00042 modification. 00043 ==> THIS IS NO LONGER TRUE USING BFD. WE CAN GENERATE ANY BYTE ORDER 00044 FOR THE HEADER, AND READ ANY BYTE ORDER. PREFERENCE WOULD BE TO 00045 USE LITTLE-ENDIAN BYTE ORDER THROUGHOUT, REGARDLESS OF HOST. <== 00046 00047 o The downloader ('comm960') takes care to generate a pseudo-header 00048 with correct (i80960) byte-ordering before shipping text and data 00049 off to the NINDY monitor in the target systems. Symbols and 00050 relocation info are never sent to the target. */ 00051 00052 #define BMAGIC 0415 00053 /* We don't accept the following (see N_BADMAG macro). 00054 They're just here so GNU code will compile. */ 00055 #define OMAGIC 0407 /* old impure format */ 00056 #define NMAGIC 0410 /* read-only text */ 00057 #define ZMAGIC 0413 /* demand load format */ 00058 00059 /* FILE HEADER 00060 All 'lengths' are given as a number of bytes. 00061 All 'alignments' are for relinkable files only; an alignment of 00062 'n' indicates the corresponding segment must begin at an 00063 address that is a multiple of (2**n). */ 00064 struct external_exec 00065 { 00066 /* Standard stuff */ 00067 unsigned char e_info[4]; /* Identifies this as a b.out file */ 00068 unsigned char e_text[4]; /* Length of text */ 00069 unsigned char e_data[4]; /* Length of data */ 00070 unsigned char e_bss[4]; /* Length of uninitialized data area */ 00071 unsigned char e_syms[4]; /* Length of symbol table */ 00072 unsigned char e_entry[4]; /* Runtime start address */ 00073 unsigned char e_trsize[4]; /* Length of text relocation info */ 00074 unsigned char e_drsize[4]; /* Length of data relocation info */ 00075 00076 /* Added for i960 */ 00077 unsigned char e_tload[4]; /* Text runtime load address */ 00078 unsigned char e_dload[4]; /* Data runtime load address */ 00079 unsigned char e_talign[1]; /* Alignment of text segment */ 00080 unsigned char e_dalign[1]; /* Alignment of data segment */ 00081 unsigned char e_balign[1]; /* Alignment of bss segment */ 00082 unsigned char e_relaxable[1];/* Assembled with enough info to allow linker to relax */ 00083 }; 00084 00085 #define EXEC_BYTES_SIZE (sizeof (struct external_exec)) 00086 00087 /* These macros use the a_xxx field names, since they operate on the exec 00088 structure after it's been byte-swapped and realigned on the host machine. */ 00089 #define N_BADMAG(x) (((x).a_info)!=BMAGIC) 00090 #define N_TXTOFF(x) EXEC_BYTES_SIZE 00091 #define N_DATOFF(x) ( N_TXTOFF(x) + (x).a_text ) 00092 #define N_TROFF(x) ( N_DATOFF(x) + (x).a_data ) 00093 #define N_TRELOFF N_TROFF 00094 #define N_DROFF(x) ( N_TROFF(x) + (x).a_trsize ) 00095 #define N_DRELOFF N_DROFF 00096 #define N_SYMOFF(x) ( N_DROFF(x) + (x).a_drsize ) 00097 #define N_STROFF(x) ( N_SYMOFF(x) + (x).a_syms ) 00098 #define N_DATADDR(x) ( (x).a_dload ) 00099 00100 /* Address of text segment in memory after it is loaded. */ 00101 #if !defined (N_TXTADDR) 00102 #define N_TXTADDR(x) 0 00103 #endif 00104 00105 /* A single entry in the symbol table. */ 00106 struct nlist 00107 { 00108 union 00109 { 00110 char* n_name; 00111 struct nlist * n_next; 00112 long n_strx; /* Index into string table */ 00113 } n_un; 00114 00115 unsigned char n_type; /* See below */ 00116 char n_other; /* Used in i80960 support -- see below */ 00117 short n_desc; 00118 unsigned long n_value; 00119 }; 00120 00121 00122 /* Legal values of n_type. */ 00123 #define N_UNDF 0 /* Undefined symbol */ 00124 #define N_ABS 2 /* Absolute symbol */ 00125 #define N_TEXT 4 /* Text symbol */ 00126 #define N_DATA 6 /* Data symbol */ 00127 #define N_BSS 8 /* BSS symbol */ 00128 #define N_FN 31 /* Filename symbol */ 00129 00130 #define N_EXT 1 /* External symbol (OR'd in with one of above) */ 00131 #define N_TYPE 036 /* Mask for all the type bits */ 00132 #define N_STAB 0340 /* Mask for all bits used for SDB entries */ 00133 00134 /* MEANING OF 'n_other' 00135 00136 If non-zero, the 'n_other' fields indicates either a leaf procedure or 00137 a system procedure, as follows: 00138 00139 1 <= n_other <= 32 : 00140 The symbol is the entry point to a system procedure. 00141 'n_value' is the address of the entry, as for any other 00142 procedure. The system procedure number (which can be used in 00143 a 'calls' instruction) is (n_other-1). These entries come from 00144 '.sysproc' directives. 00145 00146 n_other == N_CALLNAME 00147 the symbol is the 'call' entry point to a leaf procedure. 00148 The *next* symbol in the symbol table must be the corresponding 00149 'bal' entry point to the procedure (see following). These 00150 entries come from '.leafproc' directives in which two different 00151 symbols are specified (the first one is represented here). 00152 00153 00154 n_other == N_BALNAME 00155 the symbol is the 'bal' entry point to a leaf procedure. 00156 These entries result from '.leafproc' directives in which only 00157 one symbol is specified, or in which the same symbol is 00158 specified twice. 00159 00160 Note that an N_CALLNAME entry *must* have a corresponding N_BALNAME entry, 00161 but not every N_BALNAME entry must have an N_CALLNAME entry. */ 00162 #define N_CALLNAME ((char)-1) 00163 #define N_BALNAME ((char)-2) 00164 #define IS_CALLNAME(x) (N_CALLNAME == (x)) 00165 #define IS_BALNAME(x) (N_BALNAME == (x)) 00166 #define IS_OTHER(x) ((x)>0 && (x) <=32) 00167 00168 #define b_out_relocation_info relocation_info 00169 struct relocation_info 00170 { 00171 int r_address; /* File address of item to be relocated. */ 00172 unsigned 00173 #define r_index r_symbolnum 00174 r_symbolnum:24, /* Index of symbol on which relocation is based, 00175 if r_extern is set. Otherwise set to 00176 either N_TEXT, N_DATA, or N_BSS to 00177 indicate section on which relocation is 00178 based. */ 00179 r_pcrel:1, /* 1 => relocate PC-relative; else absolute 00180 On i960, pc-relative implies 24-bit 00181 address, absolute implies 32-bit. */ 00182 r_length:2, /* Number of bytes to relocate: 00183 0 => 1 byte 00184 1 => 2 bytes -- used for 13 bit pcrel 00185 2 => 4 bytes. */ 00186 r_extern:1, 00187 r_bsr:1, /* Something for the GNU NS32K assembler. */ 00188 r_disp:1, /* Something for the GNU NS32K assembler. */ 00189 r_callj:1, /* 1 if relocation target is an i960 'callj'. */ 00190 r_relaxable:1; /* 1 if enough info is left to relax the data. */ 00191 };
1.5.6