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[/] [or1k/] [trunk/] [insight/] [gdb/] [nindy-share/] [b.out.h] - Blame information for rev 1765

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1 578 markom
/*  Copyright 1992 Free Software Foundation, Inc.
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 *
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 * This file is a modified version of 'a.out.h'.  It is to be used in all
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 * all GNU tools modified to support the i80960 (or tools that operate on
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 * object files created by such tools).
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 *
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 * All i80960 development is done in a CROSS-DEVELOPMENT environment.  I.e.,
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 * object code is generated on, and executed under the direction of a symbolic
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 * debugger running on, a host system.  We do not want to be subject to the
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 * vagaries of which host it is or whether it supports COFF or a.out format,
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 * or anything else.  We DO want to:
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 *
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 *      o always generate the same format object files, regardless of host.
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 *
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 *      o have an 'a.out' header that we can modify for our own purposes
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 *        (the 80960 is typically an embedded processor and may require
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 *        enhanced linker support that the normal a.out.h header can't
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 *        accommodate).
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 *
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 * As for byte-ordering, the following rules apply:
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 *
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 *      o Text and data that is actually downloaded to the target is always
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 *        in i80960 (little-endian) order.
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 *
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 *      o All other numbers (in the header, symbols, relocation directives)
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 *        are in host byte-order:  object files CANNOT be lifted from a
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 *        little-end host and used on a big-endian (or vice versa) without
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 *        modification.
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 *
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 *      o The downloader ('comm960') takes care to generate a pseudo-header
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 *        with correct (i80960) byte-ordering before shipping text and data
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 *        off to the NINDY monitor in the target systems.  Symbols and
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 *        relocation info are never sent to the target.
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 */
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#define BMAGIC  0415
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/* We don't accept the following (see N_BADMAG macro).
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 * They're just here so GNU code will compile.
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 */
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#define OMAGIC  0407            /* old impure format */
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#define NMAGIC  0410            /* read-only text */
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#define ZMAGIC  0413            /* demand load format */
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/* FILE HEADER
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 *      All 'lengths' are given as a number of bytes.
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 *      All 'alignments' are for relinkable files only;  an alignment of
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 *              'n' indicates the corresponding segment must begin at an
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 *              address that is a multiple of (2**n).
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 */
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struct exec {
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        /* Standard stuff */
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        unsigned long a_magic;  /* Identifies this as a b.out file      */
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        unsigned long a_text;   /* Length of text                       */
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        unsigned long a_data;   /* Length of data                       */
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        unsigned long a_bss;    /* Length of runtime uninitialized data area */
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        unsigned long a_syms;   /* Length of symbol table               */
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        unsigned long a_entry;  /* Runtime start address                */
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        unsigned long a_trsize; /* Length of text relocation info       */
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        unsigned long a_drsize; /* Length of data relocation info       */
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        /* Added for i960 */
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        unsigned long a_tload;  /* Text runtime load address            */
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        unsigned long a_dload;  /* Data runtime load address            */
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        unsigned char a_talign; /* Alignment of text segment            */
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        unsigned char a_dalign; /* Alignment of data segment            */
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        unsigned char a_balign; /* Alignment of bss segment             */
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        unsigned char unused;   /* (Just to make struct size a multiple of 4) */
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};
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#define N_BADMAG(x)     (((x).a_magic)!=BMAGIC)
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#define N_TXTOFF(x)     ( sizeof(struct exec) )
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#define N_DATOFF(x)     ( N_TXTOFF(x) + (x).a_text )
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#define N_TROFF(x)      ( N_DATOFF(x) + (x).a_data )
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#define N_DROFF(x)      ( N_TROFF(x) + (x).a_trsize )
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#define N_SYMOFF(x)     ( N_DROFF(x) + (x).a_drsize )
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#define N_STROFF(x)     ( N_SYMOFF(x) + (x).a_syms )
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/* A single entry in the symbol table
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 */
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struct nlist {
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        union {
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                char    *n_name;
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                struct nlist *n_next;
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                long    n_strx;         /* Index into string table      */
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        } n_un;
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        unsigned char n_type;   /* See below                            */
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        char    n_other;        /* Used in i80960 support -- see below  */
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        short   n_desc;
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        unsigned long n_value;
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};
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/* Legal values of n_type
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 */
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#define N_UNDF  0        /* Undefined symbol     */
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#define N_ABS   2       /* Absolute symbol      */
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#define N_TEXT  4       /* Text symbol          */
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#define N_DATA  6       /* Data symbol          */
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#define N_BSS   8       /* BSS symbol           */
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#define N_FN    31      /* Filename symbol      */
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#define N_EXT   1       /* External symbol (OR'd in with one of above)  */
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#define N_TYPE  036     /* Mask for all the type bits                   */
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#define N_STAB  0340    /* Mask for all bits used for SDB entries       */
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/* MEANING OF 'n_other'
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 *
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 * If non-zero, the 'n_other' fields indicates either a leaf procedure or
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 * a system procedure, as follows:
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 *
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 *      1 <= n_other <= 32 :
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 *              The symbol is the entry point to a system procedure.
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 *              'n_value' is the address of the entry, as for any other
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 *              procedure.  The system procedure number (which can be used in
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 *              a 'calls' instruction) is (n_other-1).  These entries come from
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 *              '.sysproc' directives.
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 *
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 *      n_other == N_CALLNAME
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 *              the symbol is the 'call' entry point to a leaf procedure.
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 *              The *next* symbol in the symbol table must be the corresponding
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 *              'bal' entry point to the procedure (see following).  These
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 *              entries come from '.leafproc' directives in which two different
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 *              symbols are specified (the first one is represented here).
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 *
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 *
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 *      n_other == N_BALNAME
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 *              the symbol is the 'bal' entry point to a leaf procedure.
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 *              These entries result from '.leafproc' directives in which only
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 *              one symbol is specified, or in which the same symbol is
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 *              specified twice.
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 *
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 * Note that an N_CALLNAME entry *must* have a corresponding N_BALNAME entry,
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 * but not every N_BALNAME entry must have an N_CALLNAME entry.
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 */
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#define N_CALLNAME      -1
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#define N_BALNAME       -2
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struct relocation_info {
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        int      r_address;     /* File address of item to be relocated */
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        unsigned
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                r_symbolnum:24,/* Index of symbol on which relocation is based*/
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                r_pcrel:1,      /* 1 => relocate PC-relative; else absolute
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                                 *      On i960, pc-relative implies 24-bit
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                                 *      address, absolute implies 32-bit.
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                                 */
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                r_length:2,     /* Number of bytes to relocate:
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                                 *      0 => 1 byte
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                                 *      1 => 2 bytes
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                                 *      2 => 4 bytes -- only value used for i960
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                                 */
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                r_extern:1,
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                r_bsr:1,        /* Something for the GNU NS32K assembler */
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                r_disp:1,       /* Something for the GNU NS32K assembler */
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                r_callj:1,      /* 1 if relocation target is an i960 'callj' */
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                nuthin:1;       /* Unused                               */
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};

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