/*
	Copyright 1981
	Alcyon Corporation
	8716 Production Ave.
	San Diego, Ca.  92121
*/

/* reduce long relative branches to short if possible*/

#include "as68.h"
int  nitleft;
char tfilname[];
int p2gi();
long lseek();
pass1a()
{
	register long reduced;
	register int i, wsize;
	register long oldpos,newpos;	/* Old and new file seek pointers */
	register j;			/* temp				  */

	pitix = itbuf;
	nitleft = 0;
	reduced = 0; itoffset = 0; stbuf[0].itrl = 0;
	wsize = 3*sizeof stbuf[0];	/* [vlh] don't calculate many times */
	close(itfn);
	LASTCHTFN = itfnc;
	itfn = openfi(tfilname,2,1);	/*open it for update*/
	while(ristb()) {
		opcpt = stbuf[2].itop.ptrw2;	/*ptr to opcode entry in main tab*/
		if(!(opcpt->flags&OPDR)) {	/*not a directive*/
			format = (opcpt->flags)&OPFF;
			p1inlen = stbuf[1].itrl;	/*pass 1 instr length guess*/
			if(((format==6 && p1inlen==4) || opcpt==jsrptr) &&
			  (rlflg=stbuf[3].itrl)==TEXT) {
				nite = stbuf[0].itrl & 0377;/* # of it entries */
				pnite = &stbuf[nite].itty;	/*ptr to end of stmt*/
				modelen = stbuf[2].itrl;	/*instr mode length*/
				opdix = ITOP1;				/*first operand*/
				pitw = &stbuf[ITOP1].itty;	/*ptr to first operand*/
				loctr = stbuf[3].itop - reduced;
				expr(&p2gi);
				ival =- loctr+2L;
				if(itype==ITCN && !extflg && reloc!=ABS) {
					if(format==9) {		/*jsr*/
						i = (ival>= -128 && ival<=127) ? p1inlen-2 :
							(ival>= -32768 && ival<=32767) ? p1inlen-4 : 0;
						if (!i)
							continue;
						stbuf[2].itop.ptrw2 = bsrptr;	/*chng to bsr*/
					}
					else if(ival>= -128 && ival<=127) {
						i = 2;		/*[vlh]was 4 for ival=2*/
						if (!ival) stbuf[2].itop.ptrw2 = nopptr;
					}
					else
						continue;
					fixsyadr(i);
					reduced =+ i;
					stbuf[1].itrl =- i;		/*reduced somewhat*/
					if(!stbuf[1].itrl)
						stbuf[1].itrl = -1;	/*ignore flag*/
					oldpos=lseek(itfn,0L,1); /* Remember current position */
					newpos= itoffset -
						(stbuf[0].itrl*sizeof stbuf[0]);
					if(lseek(itfn,newpos,0) < 0) {
						rpterr("seek error on it file\n");
						abort();
					}
					if(write(itfn,&stbuf[0],wsize) != wsize) {
						rpterr("write error on it file\n");
						abort();
					}
					lseek(itfn,oldpos,0);
				}
			}
		}
		else if(opcpt == endptr) {
			savelc[TEXT] =- reduced;
			return;
		}
	}
}

/* fix all symbol addresses that are text based and greater than loctr*/
/*   fix means subtract 2 from them*/
fixsyadr(al)
{
	register char **sx1, **sx2;
	register l;

	l = al;
/* loop thru symbol initial reference table*/
	for(sx1= sirt; sx1<&sirt[SZIRT-1]; sx1 =+ 2) {
		if(*(sx2 = sx1+1)==0)		/* this chain is empty*/
			continue;

/* symbols on one chain*/
		sx2 = *sx2;	/*first entry on this chain*/
		while(1) {
			if((sx2->flags&SYDF || sx2->flags&SYPC) && sx2->flags&SYRO &&
			    sx2->vl1 > loctr)		/* [vlh] */
				sx2->vl1 =- l;
			if(sx2 == *sx1)	/*end of chain*/
				break;
			sx2 = sx2->tlnk;	/*next entry in chain*/
		}
	}
}