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      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 (C) 2001-2014 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 3 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,
     20    MA 02110-1301, USA.  */
     21 
     22 /* All i80960 development is done in a CROSS-DEVELOPMENT environment.  I.e.,
     23    object code is generated on, and executed under the direction of a symbolic
     24    debugger running on, a host system.  We do not want to be subject to the
     25    vagaries of which host it is or whether it supports COFF or a.out format,
     26    or anything else.  We DO want to:
     27 
     28   	o always generate the same format object files, regardless of host.
     29 
     30  	o have an 'a.out' header that we can modify for our own purposes
     31  	  (the 80960 is typically an embedded processor and may require
     32  	  enhanced linker support that the normal a.out.h header can't
     33  	  accommodate).
     34 
     35   As for byte-ordering, the following rules apply:
     36 
     37  	o Text and data that is actually downloaded to the target is always
     38  	  in i80960 (little-endian) order.
     39 
     40  	o All other numbers (in the header, symbols, relocation directives)
     41  	  are in host byte-order:  object files CANNOT be lifted from a
     42  	  little-end host and used on a big-endian (or vice versa) without
     43  	  modification.
     44   ==> THIS IS NO LONGER TRUE USING BFD.  WE CAN GENERATE ANY BYTE ORDER
     45       FOR THE HEADER, AND READ ANY BYTE ORDER.  PREFERENCE WOULD BE TO
     46       USE LITTLE-ENDIAN BYTE ORDER THROUGHOUT, REGARDLESS OF HOST.  <==
     47 
     48  	o The downloader ('comm960') takes care to generate a pseudo-header
     49  	  with correct (i80960) byte-ordering before shipping text and data
     50  	  off to the NINDY monitor in the target systems.  Symbols and
     51  	  relocation info are never sent to the target.  */
     52 
     53 #define BMAGIC	0415
     54 /* We don't accept the following (see N_BADMAG macro).
     55    They're just here so GNU code will compile.  */
     56 #define	OMAGIC	0407		/* old impure format */
     57 #define	NMAGIC	0410		/* read-only text */
     58 #define	ZMAGIC	0413		/* demand load format */
     59 
     60 /* FILE HEADER
     61   	All 'lengths' are given as a number of bytes.
     62   	All 'alignments' are for relinkable files only;  an alignment of
     63   		'n' indicates the corresponding segment must begin at an
     64   		address that is a multiple of (2**n).  */
     65 struct external_exec
     66   {
     67     /* Standard stuff */
     68     unsigned char e_info[4];	/* Identifies this as a b.out file */
     69     unsigned char e_text[4];	/* Length of text */
     70     unsigned char e_data[4];	/* Length of data */
     71     unsigned char e_bss[4];	/* Length of uninitialized data area */
     72     unsigned char e_syms[4];	/* Length of symbol table */
     73     unsigned char e_entry[4];	/* Runtime start address */
     74     unsigned char e_trsize[4];	/* Length of text relocation info */
     75     unsigned char e_drsize[4];	/* Length of data relocation info */
     76 
     77     /* Added for i960 */
     78     unsigned char e_tload[4];	/* Text runtime load address */
     79     unsigned char e_dload[4];	/* Data runtime load address */
     80     unsigned char e_talign[1];	/* Alignment of text segment */
     81     unsigned char e_dalign[1];	/* Alignment of data segment */
     82     unsigned char e_balign[1];	/* Alignment of bss segment */
     83     unsigned char e_relaxable[1];/* Assembled with enough info to allow linker to relax */
     84   };
     85 
     86 #define	EXEC_BYTES_SIZE	(sizeof (struct external_exec))
     87 
     88 /* These macros use the a_xxx field names, since they operate on the exec
     89    structure after it's been byte-swapped and realigned on the host machine.  */
     90 #define N_BADMAG(x)	(((x).a_info)!=BMAGIC)
     91 #define N_TXTOFF(x)	EXEC_BYTES_SIZE
     92 #define N_DATOFF(x)	( N_TXTOFF(x) + (x).a_text )
     93 #define N_TROFF(x)	( N_DATOFF(x) + (x).a_data )
     94 #define N_TRELOFF	N_TROFF
     95 #define N_DROFF(x)	( N_TROFF(x) + (x).a_trsize )
     96 #define N_DRELOFF	N_DROFF
     97 #define N_SYMOFF(x)	( N_DROFF(x) + (x).a_drsize )
     98 #define N_STROFF(x)	( N_SYMOFF(x) + (x).a_syms )
     99 #define N_DATADDR(x)	( (x).a_dload )
    100 
    101 /* Address of text segment in memory after it is loaded.  */
    102 #if !defined (N_TXTADDR)
    103 #define N_TXTADDR(x) 0
    104 #endif
    105 
    106 /* A single entry in the symbol table.  */
    107 struct nlist
    108   {
    109     union
    110       {
    111 	char*          n_name;
    112 	struct nlist * n_next;
    113 	long	       n_strx;	/* Index into string table	*/
    114       } n_un;
    115 
    116     unsigned char n_type;	/* See below				*/
    117     char	  n_other;	/* Used in i80960 support -- see below	*/
    118     short	  n_desc;
    119     unsigned long n_value;
    120   };
    121 
    122 
    123 /* Legal values of n_type.  */
    124 #define N_UNDF	0	/* Undefined symbol	*/
    125 #define N_ABS	2	/* Absolute symbol	*/
    126 #define N_TEXT	4	/* Text symbol		*/
    127 #define N_DATA	6	/* Data symbol		*/
    128 #define N_BSS	8	/* BSS symbol		*/
    129 #define N_FN	31	/* Filename symbol	*/
    130 
    131 #define N_EXT	1	/* External symbol (OR'd in with one of above)	*/
    132 #define N_TYPE	036	/* Mask for all the type bits			*/
    133 #define N_STAB	0340	/* Mask for all bits used for SDB entries 	*/
    134 
    135 /* MEANING OF 'n_other'
    136 
    137   If non-zero, the 'n_other' fields indicates either a leaf procedure or
    138   a system procedure, as follows:
    139 
    140  	1 <= n_other <= 32 :
    141  		The symbol is the entry point to a system procedure.
    142  		'n_value' is the address of the entry, as for any other
    143  		procedure.  The system procedure number (which can be used in
    144  		a 'calls' instruction) is (n_other-1).  These entries come from
    145  		'.sysproc' directives.
    146 
    147  	n_other == N_CALLNAME
    148  		the symbol is the 'call' entry point to a leaf procedure.
    149  		The *next* symbol in the symbol table must be the corresponding
    150  		'bal' entry point to the procedure (see following).  These
    151  		entries come from '.leafproc' directives in which two different
    152  		symbols are specified (the first one is represented here).
    153 
    154 
    155  	n_other == N_BALNAME
    156  		the symbol is the 'bal' entry point to a leaf procedure.
    157  		These entries result from '.leafproc' directives in which only
    158  		one symbol is specified, or in which the same symbol is
    159  		specified twice.
    160 
    161   Note that an N_CALLNAME entry *must* have a corresponding N_BALNAME entry,
    162   but not every N_BALNAME entry must have an N_CALLNAME entry.  */
    163 #define N_CALLNAME	((char)-1)
    164 #define N_BALNAME	((char)-2)
    165 #define IS_CALLNAME(x)	(N_CALLNAME == (x))
    166 #define IS_BALNAME(x)	(N_BALNAME == (x))
    167 #define IS_OTHER(x)	((x)>0 && (x) <=32)
    168 
    169 #define b_out_relocation_info relocation_info
    170 struct relocation_info
    171   {
    172     int	 r_address;	/* File address of item to be relocated.  */
    173     unsigned
    174 #define r_index r_symbolnum
    175     r_symbolnum:24,	/* Index of symbol on which relocation is based,
    176 			   if r_extern is set.  Otherwise set to
    177 			   either N_TEXT, N_DATA, or N_BSS to
    178 			   indicate section on which relocation is
    179 			   based.  */
    180       r_pcrel:1,	/* 1 => relocate PC-relative; else absolute
    181 			   On i960, pc-relative implies 24-bit
    182 			   address, absolute implies 32-bit.  */
    183       r_length:2,	/* Number of bytes to relocate:
    184 			   0 => 1 byte
    185 			   1 => 2 bytes -- used for 13 bit pcrel
    186 			   2 => 4 bytes.  */
    187       r_extern:1,
    188       r_bsr:1,		/* Something for the GNU NS32K assembler.  */
    189       r_disp:1,		/* Something for the GNU NS32K assembler.  */
    190       r_callj:1,	/* 1 if relocation target is an i960 'callj'.  */
    191       r_relaxable:1;	/* 1 if enough info is left to relax the data.  */
    192 };
    193