asmain.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

	for (cp = (char *)&environ, ub = sbrk(0); cp < ub; cp++){
		if (cp[0] != '@') continue;
		if (cp[1] != '(') continue;
		if (cp[2] != '#') continue;
		if (cp[3] != ')') continue;
		fputc('\t', place);
		for (cp += 4; cp < ub; cp++){
			if (*cp == 0) break;
			if (*cp == '>') break;
			if (*cp == '\n') break;
			fputc(*cp, place);
		}
		fputc('\n', place);
	}
}

initialize()
{
	if (signal(SIGINT, SIG_IGN) != SIG_IGN)
		signal(SIGINT, delexit);
	/*
	 *	Install symbols in the table
	 */
	symtabinit();
	syminstall();
	/*
	 *	Build the expression parser accelerator token sets
	 */
	buildtokensets();		
}

zeroorigins()
{
	register	int	locindex;
	/*
	 *	Mark usedot: the first NLOC slots are for named text segments,
	 *	the next for named data segments.
	 */
	for (locindex = 0; locindex < NLOC; locindex++){
		usedot[locindex].e_xtype = XTEXT;
		usedot[NLOC + locindex].e_xtype = XDATA;
		usedot[locindex].e_xvalue = 0;
		usedot[NLOC + locindex].e_xvalue = 0;
	}
}

zerolocals()
{
	register	int	i;

	for (i = 0; i <= 9; i++) {
		lgensym[i] = 1;
		genref[i] = 0;
	}
}

i_pass1()
{
	FILE	*tempopen();
	if (useVM == 0)
		tokfile = tempopen(tokfilename, "T");
	strfile = tempopen(strfilename, "S");
	/*
	 *	write out the string length.
	 *	This will be overwritten when the
	 *	strings are tacked onto the growing a.out file
	 */
	strfilepos = sizeof(int);
	fwrite(&strfilepos, sizeof(int), 1, strfile);

	inittokfile();
	initijxxx();
}

FILE *tempopen(tname, part)
	char	*tname;
	char	*part;
{
	FILE	*file;
	sprintf(tname, "%s%sas%s%05d",
		tmpdirprefix,
		(tmpdirprefix[strlen(tmpdirprefix)-1] != '/') ? "/" : 0,
		part,
		getpid());
	file = fopen(tname, "w");
	if (file == NULL) {
		yyerror("Bad pass 1 temporary file for writing %s", tname);
		delexit();
	}
	return(file);
}

pass1()
{
	register	int	i;

	passno = 1;
	dotp = &usedot[0];
	txtfil = (BFILE *)0;
	relfil = (struct relbufdesc *)0;

	if (ninfiles == 0){		/*take the input from stdin directly*/
		lineno = 1;
		dotsname = "<stdin>";

		yyparse();
	} else {		/*we have the names tanked*/
		for (i = 0; i < ninfiles; i++){
			new_dot_s(innames[i]);
			if (freopen(innames[i], "r", stdin) == NULL) {
				yyerror( "Can't open source file %s\n",
					innames[i]);
				exit(2);
			}
			/* stdio is NOT used to read the input characters */
			/* we use read directly, into our own buffers */
			yyparse();
		}
	}

	closetokfile();		/*kick out the last buffered intermediate text*/
}

testlocals()
{
	register	int	i;
	for (i = 0; i <= 9; i++) {
		if (genref[i])
			yyerror("Reference to undefined local label %df", i);
		lgensym[i] = 1;
		genref[i] = 0;
	}
}

pass1_5()
{
	sortsymtab();
#ifdef DEBUG
	if (debug) dumpsymtab();
#endif
	jxxxfix();
#ifdef DEBUG
	if (debug) dumpsymtab();
#endif
}

open_a_out()
{
	struct stat stb;
	/*
	 *	Open up the a.out file now, and get set to build
	 *	up offsets into it for all of the various text,data
	 *	text relocation and data relocation segments.
	 */
	a_out_file = fopen(outfile, "w");
	if (a_out_file == NULL) {
		yyerror("Cannot create %s", outfile);
		delexit();
	}
	biofd = a_out_file->_file;
	fstat(biofd,&stb);
	biobufsize = stb.st_blksize;
	a_out_off = 0;
}

roundsegments()
{
	register	int	locindex;
	register	long	v;
	/*
	 *	round and assign text segment origins
	 *	the exec header always goes in usefile[0]
	 */
	tsize = 0;
	for (locindex=0; locindex<NLOC; locindex++) {
		v = round(usedot[locindex].e_xvalue, FW);
		usedot[locindex].e_xvalue = tsize;
		if ((locindex == 0) || (v != 0) ){
			usefile[locindex] = (BFILE *)Calloc(1, sizeof(BFILE));
			bopen(usefile[locindex], a_out_off);
			if (locindex == 0)
				a_out_off = sizeof (struct exec);
		} else {
			usefile[locindex] = (BFILE *)-1;
		}
		tsize += v;
		a_out_off += v;
	}
	/*
	 *		Round and assign data segment origins.
	 */
	datbase = round(tsize, FW);
	for (locindex=0; locindex<NLOC; locindex++) {
		v = round(usedot[NLOC+locindex].e_xvalue, FW);
		usedot[NLOC+locindex].e_xvalue = datbase + dsize;
		if (v != 0){
			usefile[NLOC + locindex] = (BFILE *)Calloc(1,sizeof(BFILE));
			bopen(usefile[NLOC + locindex], a_out_off);
		} else {
			usefile[NLOC + locindex] = (BFILE *)-1;
		}
		dsize += v;
		a_out_off += v;
	}
	/*
	 *	Assign final values to symbols
	 */
	hdr.a_bss = dsize;
	freezesymtab();		/* this touches hdr.a_bss */
	stabfix();
	/*
	 *	Set up the relocation information "files" to
	 *	be zero; outrel takes care of the rest
	 */
	for (locindex = 0; locindex < NLOC + NLOC; locindex++){
		rusefile[locindex] = (struct relbufdesc *)0;
	}
}

build_hdr()
{
	/*
	 *	Except for the text and data relocation sizes,
	 *	calculate the final values for the header
	 *	
	 *	Write out the initial copy; we to come 
	 *	back later and patch up a_trsize and a_drsize,
	 *	and overwrite this first version of the header.
	 */
	hdr.a_magic = MAGIC;
	hdr.a_text = tsize;
	hdr.a_data = dsize;
	hdr.a_bss -= dsize;
	hdr.a_syms = sizesymtab();	/* Does not include string pool length */
	hdr.a_entry = 0;
	hdr.a_trsize = 0;
	hdr.a_drsize = 0;

	bwrite((char *)&hdr, sizeof(hdr), usefile[0]);
}

i_pass2()
{
	if (useVM == 0) {
		fclose(tokfile);
		tokfile = fopen(tokfilename, "r");
		if (tokfile==NULL) {
		   yyerror("Bad pass 2 temporary file for reading %s", tokfilename);
		   delexit();
		}
	}
	fclose(strfile);
	strfile = fopen(strfilename, "r");
}

pass2()
{
#ifdef DEBUG
	if (debug)
		printf("\n\n\n\t\tPASS 2\n\n\n\n");
#endif DEBUG
	passno = 2;
	lineno = 1;
	dotp = &usedot[0];
	txtfil = usefile[0];	/* already opened (always!) */
	relfil = 0;		/* outrel takes care of the rest */
	initoutrel();

	inittokfile();

	yyparse();

	closetokfile();
}

fillsegments()
{
	int	locindex;
	/*
	 *	Round text and data segments to FW by appending zeros
	 */
	for (locindex = 0; locindex < NLOC + NLOC; locindex++) {
		if (usefile[locindex]) {
			txtfil = usefile[locindex];
			dotp = &usedot[locindex];
			while (usedot[locindex].e_xvalue & FW)
				outb(0);
		}
	}
}

reloc_syms()
{
	u_long	closerelfil();
	/*
	 *	Move the relocation information to a.out
	 *	a_out_off is the offset so far:
	 *	exec + text segments + data segments
	 */
	relocfile = (BFILE *)Calloc(1,sizeof(BFILE));
	bopen(relocfile, a_out_off);
	a_out_off += closeoutrel(relocfile);

	hdr.a_trsize = trsize;
	hdr.a_drsize = drsize;
	if (readonlydata) {
		hdr.a_text += hdr.a_data;
		hdr.a_data = 0;
		hdr.a_trsize += hdr.a_drsize;
		hdr.a_drsize = 0;
	}
	/*
	 *	Output the symbol table and the string pool
	 *
	 *	We must first rewind the string pool file to its beginning,
	 *	in case it was seek'ed into for fetching ascii and asciz
	 *	strings.
	 */
	fseek(strfile, 0, 0);
	symwrite(relocfile);
}

fix_a_out()
{
	if (lseek(a_out_file->_file, 0L, 0) < 0L)
		yyerror("Reposition for header rewrite fails");
	if (write(a_out_file->_file, (char *)&hdr, sizeof (struct exec)) < 0)
		yyerror("Rewrite of header fails");
}

delexit()
{
	delete();
	if (passno == 2){
		unlink(outfile);
	}
	exit(1);
}

delete()
{
	if (useVM == 0 || tokfilename[0])
		unlink(tokfilename);
	if (strfilename[0])
		unlink(strfilename);
}

sawabort()
{
	char	*fillinbuffer();
	while (fillinbuffer() != (char *)0)
		continue;
	delete();
	exit(1);	/*although the previous pass will also exit non zero*/
}

panic(fmt, a1, a2, a3, a4)
	char	*fmt;
	/*VARARGS 1*/
{
	yyerror("Assembler panic: bad internal data structure.");
	yyerror(fmt, a1, a2, a3, a4);
	delete();
	abort();
}