a.out.h

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/*
 * format of the exec header
 * known by kernel and by user programs
 */
struct exec {
	unsigned short	a_machtype;	/* machine type */
	unsigned short	a_magic;	/* magic number */
	unsigned long	a_text;		/* size of text segment */
	unsigned long	a_data;		/* size of initialized data */
	unsigned long	a_bss;		/* size of uninitialized data */
	unsigned long	a_syms;		/* size of symbol table */
	unsigned long	a_entry;	/* entry point */
	unsigned long	a_trsize;	/* size of text relocation */
	unsigned long	a_drsize;	/* size of data relocation */
};

#define	OMAGIC	0407		/* old impure format */
#define	NMAGIC	0410		/* read-only text */
#define	ZMAGIC	0413		/* demand load format */

/* machine types */

#define M_OLDSUN2	0	/* old sun-2 executable files */
#define M_68010		1	/* runs on either 68010 or 68020 */
#define M_68020		2	/* runs only on 68020 */


/*
 * memory management parameters
 */

#define	PAGSIZ		0x2000
#define	SEGSIZ		0x20000
#define	OLD_PAGSIZ	0x800	/* THIS DISAPPEARS IN RELEASE 4.0 */
#define	OLD_SEGSIZ	0x8000	/* THIS DISAPPEARS IN RELEASE 4.0 */


/*
 * returns 1 if an object file type is invalid, i.e., if the other macros
 * defined below will not yield the correct offsets.  Note that a file may
 * have N_BADMAG(x) = 0 and may be fully linked, but still may not be
 * executable.
 */

#define	N_BADMAG(x) \
	((x).a_magic!=OMAGIC && (x).a_magic!=NMAGIC && (x).a_magic!=ZMAGIC)

/*
 * relocation parameters. These are architecture-dependent
 * and can be deduced from the machine type.  They are used
 * to calculate offsets of segments within the object file;
 * See N_TXTOFF(x), etc. below.
 */

#define	N_PAGSIZ(x) \
	((x).a_machtype == M_OLDSUN2? OLD_PAGSIZ : PAGSIZ)
#define	N_SEGSIZ(x) \
	((x).a_machtype == M_OLDSUN2? OLD_SEGSIZ : SEGSIZ)


/*
 * offsets of various sections of an object file.
 */

#define	N_TXTOFF(x) \
	/* text segment */ \
	( (x).a_machtype == M_OLDSUN2 \
	? ((x).a_magic==ZMAGIC ? N_PAGSIZ(x) : sizeof (struct exec)) \
	: ((x).a_magic==ZMAGIC ? 0 : sizeof (struct exec)) )


#define	N_SYMOFF(x) \
	/* symbol table */ \
	(N_TXTOFF(x)+(x).a_text+(x).a_data+(x).a_trsize+(x).a_drsize)

#define	N_STROFF(x) \
	/* string table */ \
	(N_SYMOFF(x) + (x).a_syms)

/*
 * Macros which take exec structures as arguments and tell where the
 * various pieces will be loaded.
 */

#define N_TXTADDR(x) \
	((x).a_machtype == M_OLDSUN2? N_SEGSIZ(x) : N_PAGSIZ(x))


#define N_DATADDR(x) \
	(((x).a_magic==OMAGIC)? (N_TXTADDR(x)+(x).a_text) \
	: (N_SEGSIZ(x)+((N_TXTADDR(x)+(x).a_text-1) & ~(N_SEGSIZ(x)-1))))

#define N_BSSADDR(x)  (N_DATADDR(x)+(x).a_data)

/*
 * Format of a relocation datum.
 */

struct relocation_info {
	long	r_address;	/* address which is relocated */
unsigned int	r_symbolnum:24,	/* local symbol ordinal */
		r_pcrel:1, 	/* was relocated pc relative already */
		r_length:2,	/* 0=byte, 1=word, 2=long */
		r_extern:1,	/* does not include value of sym referenced */
		:4;		/* nothing, yet */
};

/*
 * Format of a symbol table entry
 */
struct	nlist {
	union {
		char	*n_name;	/* for use when in-core */
		long	n_strx;		/* index into file string table */
	} n_un;
	unsigned char	n_type;		/* type flag (N_TEXT,..)  */
	char	n_other;		/* unused */
	short	n_desc;			/* see <stab.h> */
	unsigned long	n_value;	/* value of symbol (or sdb offset) */
};

/*
 * Simple values for n_type.
 */
#define	N_UNDF	0x0		/* undefined */
#define	N_ABS	0x2		/* absolute */
#define	N_TEXT	0x4		/* text */
#define	N_DATA	0x6		/* data */
#define	N_BSS	0x8		/* bss */
#define	N_COMM	0x12		/* common (internal to ld) */
#define	N_FN	0x1f		/* file name symbol */

#define	N_EXT	01		/* external bit, or'ed in */
#define	N_TYPE	0x1e		/* mask for all the type bits */

/*
 * Dbx entries have some of the N_STAB bits set.
 * These are given in <stab.h>
 */
#define	N_STAB	0xe0		/* if any of these bits set, a dbx symbol */

/*
 * Format for namelist values.
 */
#define	N_FORMAT	"%08x"