fixup.h

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/****************************************************************************
*
*                            Open Watcom Project
*
*    Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
*
*  ========================================================================
*
*    This file contains Original Code and/or Modifications of Original
*    Code as defined in and that are subject to the Sybase Open Watcom
*    Public License version 1.0 (the 'License'). You may not use this file
*    except in compliance with the License. BY USING THIS FILE YOU AGREE TO
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*    provided with the Original Code and Modifications, and is also
*    available at www.sybase.com/developer/opensource.
*
*    The Original Code and all software distributed under the License are
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* Description:  WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
*               DESCRIBE IT HERE!
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****************************************************************************/


#ifndef FIXUP_H
#define FIXUP_H 1
/*
    A lot of this file assumes you're familiar with the Intel OMF book...
*/


typedef struct {
    uint_16 frame;          /* frame number of physical reference       */
    uint_32 offset;         /* offset into reference                    */
} physref;

typedef struct {
    uint_8  frame       :3; /* F_ types from pcobj.h                    */
    uint_8  target      :3; /* T_ types from pcobj.h (only T0-T3)       */
    uint_8  is_secondary:1; /* can write target in a secondary manner   */

    uint_16 frame_datum;    /* datum for different frame methods        */
    uint_16 target_datum;   /* datum for different target methods       */
    int_32  target_offset;  /* offset of target for target method       */
} logref;

typedef union {
    logref  log;
    physref phys;
} logphys;

typedef struct fixup fixup;
typedef struct fixinfo fixinfo;

#include "pcobj.h"
#include "objio.h"

/*
    The ordering of this enumerated type is depended on in several places.
*/
enum {                      /* method of fixing up location:            */
    FIX_LO_BYTE,            /* relocate lo byte of offset               */
    FIX_OFFSET,             /* relocate offset (2 bytes)                */
    FIX_BASE,               /* relocate base (2 bytes)                  */
    FIX_POINTER,            /* relocate pointer (base:offset 4 bytes)   */
    FIX_HI_BYTE,            /* relocate hi byte of offset               */
    FIX_OFFSET386,          /* relocate offset (4 bytes)                */
    FIX_POINTER386,         /* relocate pointer (base:offset 6 bytes)   */
    /* don't define more than 8 values without changing bit field */
};

struct fixup {
    fixup   *next;          /* useful for placing in linked list        */
    uint_8  loc_method      :3;
    uint_8  self_relative   :1; /* self or seg relative                 */
    uint_8  loader_resolved :1; /* loader resolved relocation           */
    uint_32 loc_offset;     /* see note below                           */
    logref  lr;             /* logical reference data                   */
};

/*
    fixup.loc_offset has two purposes:  when the fixup is built by FixGetFix,
    this field will contain the value of the "data_rec_offset" 10-bit offset
    into the previous LE/LIDATA.  When the fixup is written, this field must
    contain a similar value (10-bit number which is offset from beginning of
    most recent LE/LIDATA).  However, it is a full 32-bit wide field to allow
    other routines room to play.  i.e., in the WATCOM parser uses the 32-bit
    field as a full offset into the debugging information segments ($$TYPES or
    $$SYMBOLS); this is handled by WAT2CAN0.C.
*/

struct fixinfo {
    /* caller should not touch these fields */
    struct {
        uint_8  method;
        uint_16 datum;
    } trd[ 8 ];
};

enum fixgen_types {
    FIX_GEN_INTEL,
    FIX_GEN_PHARLAP,
    FIX_GEN_MS386
};
#define FIX_GEN_MAX     11          /* max number of bytes FixGenFix requires */

extern void FixInit( void );
extern void FixFini( void );
/*
    FixInit must be called before any other routines in this modules.
    FixFini free's any memory used by this module, along with all the
    outstanding fixups.
*/

extern fixup *FixNew( void );
/*
    Allocate memory for a new fixup.
*/


extern fixup *FixDup( const fixup *fix );
/*
    Allocate a new fixup, and copy fix into it.
*/


extern void FixKill( fixup *fix );
/*
    Free the memory used by fix.
*/


/********** the following are used for parsing fixups *************/

extern fixinfo *FixBegin( void );
/*
    Begin parsing fixups.  The structure returned contains state
    information to deal with threads.
*/

extern fixup *FixGetFix( fixinfo *info, obj_rec *objr );
/*
    Read a fixup.
*/


extern void FixGetLRef( fixinfo *info, obj_rec *objr, logref *log );
/*
    Read a logical reference.
*/


extern void FixGetPRef( fixinfo *info, obj_rec *objr, physref *phys );
/*
    Read a physical reference.
*/


extern void FixGetRef( fixinfo *info, obj_rec *objr, logphys *lp,
        int is_logical );
/*
    Read a logical or a physical reference depending on is_logical.
*/


extern void FixEnd( fixinfo *info );
/*
    Called to free the memory allocated by FixBegin.
*/


/********** the following are used for generating fixups *************/

extern size_t FixGenFix( fixup *fix, char *buf, int type );
/*
    Create the binary representation of fix, for the OMF described by
    fixgen_type type, into buf.  Returns the number of bytes written.
    buf must be at least FIX_GEN_MAX bytes large.
*/


extern size_t FixGenLRef( logref *log, char *buf, int type );
extern size_t FixGenPRef( physref *phys, char *buf, int type );
extern size_t FixGenRef( logphys *lp, int is_logical, char *buf, int type );
/*
    Generate references.  See FixGenFix comment for details.
*/


#endif