1: /* This file is a modified version of 'a.out.h'.  It is to be used in all
    2:    GNU tools modified to support the i80960 (or tools that operate on
    3:    object files created by such tools).
    4:    
    5:    Copyright 2001 Free Software Foundation, Inc.
    6: 
    7:    This program is free software; you can redistribute it and/or modify
    8:    it under the terms of the GNU General Public License as published by
    9:    the Free Software Foundation; either version 2 of the License, or
   10:    (at your option) any later version.
   11:    
   12:    This program is distributed in the hope that it will be useful,
   13:    but WITHOUT ANY WARRANTY; without even the implied warranty of
   14:    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   15:    GNU General Public License for more details.
   16:    
   17:    You should have received a copy of the GNU General Public License
   18:    along with this program; if not, write to the Free Software
   19:    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
   20:  
   21: /* All i80960 development is done in a CROSS-DEVELOPMENT environment.  I.e.,
   22:    object code is generated on, and executed under the direction of a symbolic
   23:    debugger running on, a host system.  We do not want to be subject to the
   24:    vagaries of which host it is or whether it supports COFF or a.out format,
   25:    or anything else.  We DO want to:
   26:   
   27:         o always generate the same format object files, regardless of host.
   28:  
   29:         o have an 'a.out' header that we can modify for our own purposes
   30:           (the 80960 is typically an embedded processor and may require
   31:           enhanced linker support that the normal a.out.h header can't
   32:           accommodate).
   33:  
   34:   As for byte-ordering, the following rules apply:
   35:  
   36:         o Text and data that is actually downloaded to the target is always
   37:           in i80960 (little-endian) order.
   38:  
   39:         o All other numbers (in the header, symbols, relocation directives)
   40:           are in host byte-order:  object files CANNOT be lifted from a
   41:           little-end host and used on a big-endian (or vice versa) without
   42:           modification.
   43:   ==> THIS IS NO LONGER TRUE USING BFD.  WE CAN GENERATE ANY BYTE ORDER
   44:       FOR THE HEADER, AND READ ANY BYTE ORDER.  PREFERENCE WOULD BE TO
   45:       USE LITTLE-ENDIAN BYTE ORDER THROUGHOUT, REGARDLESS OF HOST.  <==
   46:  
   47:         o The downloader ('comm960') takes care to generate a pseudo-header
   48:           with correct (i80960) byte-ordering before shipping text and data
   49:           off to the NINDY monitor in the target systems.  Symbols and
   50:           relocation info are never sent to the target.  */
   51: 
   52: #define BMAGIC  0415
   53: /* We don't accept the following (see N_BADMAG macro).
   54:    They're just here so GNU code will compile.  */
   55: #define OMAGIC  0407             /* old impure format */
   56: #define NMAGIC  0410             /* read-only text */
   57: #define ZMAGIC  0413             /* demand load format */
   58: 
   59: /* FILE HEADER
   60:         All 'lengths' are given as a number of bytes.
   61:         All 'alignments' are for relinkable files only;  an alignment of
   62:                 'n' indicates the corresponding segment must begin at an
   63:                 address that is a multiple of (2**n).  */
   64: struct external_exec
   65:   {
   66:     /* Standard stuff */
   67:     unsigned char e_info[4];    /* Identifies this as a b.out file */
   68:     unsigned char e_text[4];    /* Length of text */
   69:     unsigned char e_data[4];    /* Length of data */
   70:     unsigned char e_bss[4];     /* Length of uninitialized data area */
   71:     unsigned char e_syms[4];    /* Length of symbol table */
   72:     unsigned char e_entry[4];   /* Runtime start address */
   73:     unsigned char e_trsize[4];  /* Length of text relocation info */
   74:     unsigned char e_drsize[4];  /* Length of data relocation info */
   75: 
   76:     /* Added for i960 */
   77:     unsigned char e_tload[4];   /* Text runtime load address */
   78:     unsigned char e_dload[4];   /* Data runtime load address */
   79:     unsigned char e_talign[1];  /* Alignment of text segment */
   80:     unsigned char e_dalign[1];  /* Alignment of data segment */
   81:     unsigned char e_balign[1];  /* Alignment of bss segment */
   82:     unsigned char e_relaxable[1];/* Assembled with enough info to allow linker to relax */
   83:   };
   84: 
   85: #define EXEC_BYTES_SIZE (sizeof (struct external_exec))
   86: 
   87: /* These macros use the a_xxx field names, since they operate on the exec
   88:    structure after it's been byte-swapped and realigned on the host machine.  */
   89: #define N_BADMAG(x)     (((x).a_info)!=BMAGIC)
   90: #define N_TXTOFF(x)     EXEC_BYTES_SIZE
   91: #define N_DATOFF(x)     ( N_TXTOFF(x) + (x).a_text )
   92: #define N_TROFF(x)      ( N_DATOFF(x) + (x).a_data )
   93: #define N_TRELOFF       N_TROFF
   94: #define N_DROFF(x)      ( N_TROFF(x) + (x).a_trsize )
   95: #define N_DRELOFF       N_DROFF
   96: #define N_SYMOFF(x)     ( N_DROFF(x) + (x).a_drsize )
   97: #define N_STROFF(x)     ( N_SYMOFF(x) + (x).a_syms )
   98: #define N_DATADDR(x)    ( (x).a_dload )    
   99: 
  100: /* Address of text segment in memory after it is loaded.  */
  101: #if !defined (N_TXTADDR)
  102: #define N_TXTADDR(x) 0
  103: #endif
  104: 
  105: /* A single entry in the symbol table.  */
  106: struct nlist
  107:   {
  108:     union
  109:       {
  110:         char*          n_name;
  111:         struct nlist * n_next;
  112:         long          n_strx;    /* Index into string table */
  113:       } n_un;
  114: 
  115:     unsigned char n_type;       /* See below                          */
  116:     char          n_other;     /* Used in i80960 support -- see below      */
  117:     short         n_desc;
  118:     unsigned long n_value;
  119:   };
  120: 
  121: 
  122: /* Legal values of n_type.  */
  123: #define N_UNDF  0        /* Undefined symbol    */
  124: #define N_ABS   2 /* Absolute symbol      */
  125: #define N_TEXT  4        /* Text symbol         */
  126: #define N_DATA  6        /* Data symbol         */
  127: #define N_BSS   8 /* BSS symbol           */
  128: #define N_FN    31 /* Filename symbol      */
  129: 
  130: #define N_EXT   1 /* External symbol (OR'd in with one of above)  */
  131: #define N_TYPE  036      /* Mask for all the type bits                        */
  132: #define N_STAB  0340     /* Mask for all bits used for SDB entries   */
  133: 
  134: /* MEANING OF 'n_other'
  135:  
  136:   If non-zero, the 'n_other' fields indicates either a leaf procedure or
  137:   a system procedure, as follows:
  138:  
  139:         1 <= n_other <= 32 :
  140:                 The symbol is the entry point to a system procedure.
  141:                 'n_value' is the address of the entry, as for any other
  142:                 procedure.  The system procedure number (which can be used in
  143:                 a 'calls' instruction) is (n_other-1).  These entries come from
  144:                 '.sysproc' directives.
  145:  
  146:         n_other == N_CALLNAME
  147:                 the symbol is the 'call' entry point to a leaf procedure.
  148:                 The *next* symbol in the symbol table must be the corresponding
  149:                 'bal' entry point to the procedure (see following).  These
  150:                 entries come from '.leafproc' directives in which two different
  151:                 symbols are specified (the first one is represented here).
  152:         
  153:  
  154:         n_other == N_BALNAME
  155:                 the symbol is the 'bal' entry point to a leaf procedure.
  156:                 These entries result from '.leafproc' directives in which only
  157:                 one symbol is specified, or in which the same symbol is
  158:                 specified twice.
  159:  
  160:   Note that an N_CALLNAME entry *must* have a corresponding N_BALNAME entry,
  161:   but not every N_BALNAME entry must have an N_CALLNAME entry.  */
  162: #define N_CALLNAME      ((char)-1)
  163: #define N_BALNAME       ((char)-2)
  164: #define IS_CALLNAME(x)  (N_CALLNAME == (x))
  165: #define IS_BALNAME(x)   (N_BALNAME == (x))
  166: #define IS_OTHER(x)     ((x)>0 && (x) <=32)
  167: 
  168: #define b_out_relocation_info relocation_info
  169: struct relocation_info
  170:   {
  171:     int  r_address;     /* File address of item to be relocated.  */
  172:     unsigned
  173: #define r_index r_symbolnum
  174:     r_symbolnum:24,     /* Index of symbol on which relocation is based,
  175:                            if r_extern is set.  Otherwise set to
  176:                            either N_TEXT, N_DATA, or N_BSS to
  177:                            indicate section on which relocation is
  178:                            based.  */
  179:       r_pcrel:1,        /* 1 => relocate PC-relative; else absolute
  180:                            On i960, pc-relative implies 24-bit
  181:                            address, absolute implies 32-bit.  */
  182:       r_length:2,       /* Number of bytes to relocate:
  183:                            0 => 1 byte
  184:                            1 => 2 bytes -- used for 13 bit pcrel
  185:                            2 => 4 bytes.  */
  186:       r_extern:1,
  187:       r_bsr:1,          /* Something for the GNU NS32K assembler.  */
  188:       r_disp:1,         /* Something for the GNU NS32K assembler.  */
  189:       r_callj:1,        /* 1 if relocation target is an i960 'callj'.  */
  190:       r_relaxable:1;    /* 1 if enough info is left to relax the data.  */
  191: };