as.h

<B>Digital的Unix操作系统VAX 4.2源码</B>

 *
 *	For one byte opcodes in the basic arhitecture,
 *		I_eopcode is CORE
 *	For one byte opcodes in the new architecture definition,
 *		I_eopcode is NEW
 *	For the two byte opcodes, I_eopcode is the escape byte.
 *
 *	The assembler checks if a NEW or two byte opcode is used,
 *	and issues a warning diagnostic.
 */
/*
 *	For upward compatability reasons, we can't have the two opcodes
 *	forming an operator specifier byte(s) be physically adjacent
 *	in the instruction table.
 *	We define a structure and a constructor that is used in
 *	the instruction generator.
 */
struct Opcode{
	u_char	Op_eopcode;
	u_char	Op_popcode;
};

#define	BADPOINT	0xAAAAAAAA
/*
 *	See if a structured opcode is bad
 */
#define	ITABCHECK(o)	((itab[o.Op_eopcode] != (Iptr*)BADPOINT) && (itab[o.Op_eopcode][o.Op_popcode] != (Iptr)BADPOINT))
/*
 *	Index the itab by a structured opcode
 */
#define	ITABFETCH(o)	itab[o.Op_eopcode][o.Op_popcode]

struct	Instab{
	char	*I_name;
	u_char	I_popcode;		/* basic op code */
	char	I_nargs;
	char	I_args[6];
	u_char	I_s_tag;
	u_char	I_eopcode;
	char    I_format;               /* vector instruction format number */
	u_char	I_ctrlcode;    		/* vector instruction CMP/CVT code */
};
/*
 *	Redefinitions of fields in the struct nlist for instructions so that
 *	one saves typing, and conforms to the old naming conventions
 */
#define	i_popcode	s_nm.n_type	/* use the same field as symtab.type */
#define	i_eopcode	s_eopcode
#define	i_ctrlcode	s_ctrlcode
#define	i_nargs		s_nm.n_other	/* number of arguments */
#define	fetcharg(ptr, n) ((struct Instab *)ptr)->I_args[n]

struct	arg {				/*one argument to an instruction*/
	char	a_atype;
	char	a_areg1;
	char	a_areg2;
	char	a_dispsize;		/*usually d124, unless have B^, etc*/
	struct	exp *a_xp;
};
/*
 *	Definitions for numbers and expressions.
 */
#include "asnumber.h"
struct	exp {
	Bignum	e_number;	/* 128 bits of #, plus tag */
	char	e_xtype;
	char	e_xloc;
	struct	symtab		*e_xname;
};
#define	e_xvalue	e_number.num_num.numIl_int.Il_long
#define	e_xwvalue	e_number.num_num.numIl_int.Iw_short

#define		MINLIT		0
#define		MAXLIT		63

#define		MINBYTE		-128
#define		MAXBYTE		127
#define		MINUBYTE	0
#define		MAXUBYTE	255

#define		MINWORD		-32768
#define		MAXWORD		32767
#define		MINUWORD	0
#define		MAXUWORD	65535

#define		ISLIT(x)	(((x) >= MINLIT) && ((x) <= MAXLIT))
#define		ISBYTE(x)	(((x) >= MINBYTE) && ((x) <= MAXBYTE))
#define		ISUBYTE(x)	(((x) >= MINUBYTE) && ((x) <= MAXUBYTE))
#define		ISWORD(x)	(((x) >= MINWORD) && ((x) <= MAXWORD))
#define		ISUWORD(x)	(((x) >= MINUWORD) && ((x) <= MAXUWORD))
/*
 *	Definitions for strings.
 *
 *	Strings are stored in the string pool; see strsave(str, length)
 *	Strings are known by their length and values.
 *	A string pointer points to the beginning of the value bytes;
 *
 *	If this structure is changed, change insts also.
 */
struct	strdesc{
	int	sd_stroff;	/* offset into string file */
	short	sd_place;	/* where string is */
	u_short	sd_strlen;	/* string length */
	char	sd_string[1];	/* the string itself, flexible length */
};
/*
 *	Where a string can be.  If these are changed, also change instrs.
 */
#define	STR_FILE	0x1
#define	STR_CORE	0x2
#define	STR_BOTH	0x3

struct strdesc *savestr();

/*
 *	Global variables
 */
	extern	struct	arg	arglist[NARG];	/*building operands in instructions*/
	extern	struct	arg	varglist[NARG];	/*building operands in vector instructions*/
	extern	struct	exp	explist[NEXP];	/*building up a list of expressions*/
	extern	struct	exp	*xp;		/*current free expression*/
	/*
	 *	Communication between the scanner and the jxxx handlers.
	 *	lastnam:	the last name seen on the input
	 *	lastjxxx:	pointer to the last symbol table entry for
	 *			a jump from
	 */
	extern	struct	symtab	*lastnam;
	extern	struct	symtab	*lastjxxx;	
	/*
	 *	Lgensym is used to make up funny names for local labels.
	 *	lgensym[i] is the current funny number to put after
	 *	references to if, lgensym[i]-1 is for ib.
	 *	genref[i] is set when the label is referenced before
	 *	it is defined (i.e. 2f) so that we can be sure these
	 *	labels are always defined to avoid weird diagnostics
	 *	from the loader later.
	 */
	extern	int	lgensym[10];
	extern	char	genref[10];

	extern	struct	exp	*dotp;		/* the current dot location */
	extern	int	loctr;

	extern	struct	exec	hdr;		/* a.out header */
	extern	u_long	tsize;			/* total text size */
	extern	u_long	dsize;			/* total data size */
	extern	u_long	trsize;			/* total text relocation size */
	extern	u_long	drsize;			/* total data relocation size */
	extern	u_long	datbase;		/* base of the data segment */
	/*
	 *	Bitoff and bitfield keep track of the packing into 
	 *	bytes mandated by the expression syntax <expr> ':' <expr>
	 */
	extern	int	bitoff;	
	extern	long	bitfield;
	
	/*
	 *	The lexical analyzer builds up symbols in yytext.  Lookup
	 *	expects its argument in this buffer
	 */
	extern	char	yytext[NCPName+2];	/* text buffer for lexical */
	/*
	 *	Variables to manage the input assembler source file
	 */
	extern	int	lineno;			/*the line number*/
	extern	char	*dotsname;		/*the name of the as source*/

	extern	FILE	*tokfile;		/* temp token communication*/
	extern	FILE	*strfile;		/* temp string file*/
	extern	char	tokfilename[TNAMESIZE];	/* token file name */
	extern	char	strfilename[TNAMESIZE];	/* string file name */
	extern	int	strfilepos;		/* position in string file */

	extern	int	passno;			/* 1 or 2 */

	extern	int	anyerrs;		/*errors as'ing arguments*/
	extern	int	anywarnings;		/*warnings as'ing arguments*/
	extern	int	silent;			/*don't mention the errors*/
	extern	int	savelabels;		/*save labels in a.out*/
	extern	int	orgwarn;		/* questionable origin ? */
	extern	int	useVM;			/*use virtual memory temp file*/
	extern	int	jxxxJUMP;		/*use jmp instead of brw for jxxx */
	extern	int	readonlydata;		/*initialized data into text space*/
	extern	int	nGHnumbers;		/* GH numbers used */
	extern	int	nGHopcodes;		/* GH opcodes used */
	extern	int	nnewopcodes;		/* new opcodes used */
#ifdef DEBUG
	extern	int	debug;
	extern	int	toktrace;
#endif
	/*
	 *	Information about the instructions
	 */
	extern	struct	instab	**itab[NINST];	/*maps opcodes to instructions*/
	extern  readonly struct Instab instab[];

	extern	int	curlen;			/*current literal storage size*/
	extern	int	d124;			/*current pointer storage size*/
	
	struct	symtab	**lookup();		/*argument in yytext*/
	struct 	symtab	*symalloc();

	char	*Calloc();
	char	*ClearCalloc();

#define outb(val) {dotp->e_xvalue++; if (passno==2) bputc((val), (txtfil));}

#define outs(cp, lg) dotp->e_xvalue += (lg); if (passno == 2) bwrite((cp), (lg), (txtfil))

#define	Outb(o)	outb(o)
/*
 *	Most of the time, the argument to flushfield is a power of two constant,
 *	the calculations involving it can be optimized to shifts.
 */
#define flushfield(n) if (bitoff != 0)  Flushfield( ( (bitoff+n-1) /n ) * n)

/*
 * The biobuf structure and associated routines are used to write
 * into one file at several places concurrently.  Calling bopen
 * with a biobuf structure sets it up to write ``biofd'' starting
 * at the specified offset.  You can then use ``bwrite'' and/or ``bputc''
 * to stuff characters in the stream, much like ``fwrite'' and ``fputc''.
 * Calling bflush drains all the buffers and MUST be done before exit.
 */
struct	biobuf {
	short	b_nleft;		/* Number free spaces left in b_buf */
/* Initialize to be less than BUFSIZ initially, to boundary align in file */
	char	*b_ptr;			/* Next place to stuff characters */
	char	*b_buf;			/* Pointer to the buffer */
	off_t	b_off;			/* Current file offset */
	struct	biobuf *b_link;		/* Link in chain for bflush() */
};
#define	bputc(c,b) ((b)->b_nleft ? (--(b)->b_nleft, *(b)->b_ptr++ = (c)) \
		       : bflushc(b, c))
#define BFILE	struct biobuf

	extern	BFILE	*biobufs;	/* head of the block I/O buffer chain */
	extern	int	biofd;		/* file descriptor for block I/O file */
	extern	off_t	boffset;	/* physical position in logical file */
	extern	int	biobufsize;	/* optimal block size for I/O */
#define min(a,b) ((a) < (b) ? (a):(b))
#define movestr(to,from,len)	{register char *too = to, *fromm = from;\
				 register int length = len;\
				 if (length>0) bcopy(from,to,length);}

	/*
	 *	For each of the named .text .data segments
	 *	(introduced by .text <expr>), we maintain
	 *	the current value of the dot, and the BFILE where
	 *	the information for each of the segments is placed
	 *	during the second pass.
	 */
	extern	struct	exp	usedot[NLOC + NLOC];
	extern		BFILE	*usefile[NLOC + NLOC];
	extern		BFILE	*txtfil;/* file for text and data: into usefile */
	/*
	 *	Relocation information for each segment is accumulated
	 *	seperately from the others.  Writing the relocation
	 *	information is logically viewed as writing to one
	 *	relocation saving file for  each segment; physically
	 *	we have a bunch of buffers allocated internally that
	 *	contain the relocation information.
	 */
	struct	relbufdesc	*rusefile[NLOC + NLOC];
	struct	relbufdesc	*relfil;

struct Ctrl_word{
  unsigned vc_bits:4;             /* bits 0-3 */
  unsigned vb_bits:4;             /* bits 4-7 */
  unsigned va_bits:4;             /* bits 8-11 */
  unsigned unused_bit:1;          /* bit  12 */
  unsigned mod_bits:3  ;          /* bit  13-15 */
};

struct Vinst_arg {
  int               va_tag;       /* VCTRL, VOPND, VLTRL */
  char              va_args[3];   /* if va_tag = VCTRL: va,vb,vc */
                                  /* if va_tag = VOPND: src opnd # */
};

struct Vinst_fmt {
  u_short           vi_mod_mask;  /* modifier mask */
  u_short           vi_mod_dflt;  /* default modifiers */
  char              vi_nargs;     /* number of vector inst operands */
  struct Vinst_arg  vi_args[6];   /* up to 6 arguments per vinst */
};

union Vinst_mod {
  struct {
    short   mod_length;
    char    mod_ch[2];
  }mod_value;
  int     imod;
};

/* Definitions pertaining to vector instruction format.  */
#define         VCTRL 1
#define         VOPND 2
#define         VLTRL 3

#define         VARG1 1
#define         VARG2 (VARG1 + 1)
#define         VARG3 (VARG2 + 1)
#define         VARG4 (VARG3 + 1)
#define         VARG5 (VARG4 + 1)
#define         VARG6 (VARG5 + 1)
#define         VCODE (VARG6 + 1)

#define         VA    0
#define         VB    1
#define         VC    2

#define         mi_bit    (1)
#define         exc_bit   (1)
#define         mtf_bit   (1<<1)
#define         moe_bit   (1<<2)

#define         MOE 0x01
#define         MTF 0x02
#define         MI  0x04
#define         EXC 0x08