1File: PASS1A.C                                                            Page       1
     1   /*
     2   	Copyright 1981
     3   	Alcyon Corporation
     4   	8716 Production Ave.
     5   	San Diego, Ca.  92121
     6   */
     7    
     8   /* reduce long relative branches to short if possible*/
     9    
    10   #include "as68.h"
    11   int  nitleft;
    12   char tfilname[];
    13   int p2gi();
    14   long lseek();
    15   pass1a()
    16   {
    17   	register long reduced;
    18   	register int i, wsize;
    19   	register long oldpos,newpos;	/* Old and new file seek pointers */
    20   	register j;			/* temp				  */
    21    
    22   	pitix = itbuf;
    23   	nitleft = 0;
    24   	reduced = 0; itoffset = 0; stbuf[0].itrl = 0;
    25   	wsize = 3*sizeof stbuf[0];	/* [vlh] don't calculate many times */
    26   	close(itfn);
    27   	LASTCHTFN = itfnc;
    28   	itfn = openfi(tfilname,2,1);	/*open it for update*/
    29   	while(ristb()) {
    30   		opcpt = stbuf[2].itop.ptrw2;	/*ptr to opcode entry in main tab*/
    31   		if(!(opcpt->flags&OPDR)) {	/*not a directive*/
    32   			format = (opcpt->flags)&OPFF;
    33   			p1inlen = stbuf[1].itrl;	/*pass 1 instr length guess*/
    34   			if(((format==6 && p1inlen==4) || opcpt==jsrptr) &&
    35   			  (rlflg=stbuf[3].itrl)==TEXT) {
    36   				nite = stbuf[0].itrl & 0377;/* # of it entries */
    37   				pnite = &stbuf[nite].itty;	/*ptr to end of stmt*/
    38   				modelen = stbuf[2].itrl;	/*instr mode length*/
    39   				opdix = ITOP1;				/*first operand*/
    40   				pitw = &stbuf[ITOP1].itty;	/*ptr to first operand*/
    41   				loctr = stbuf[3].itop - reduced;
    42   				expr(&p2gi);
    43   				ival =- loctr+2L;
    44   				if(itype==ITCN && !extflg && reloc!=ABS) {
    45   					if(format==9) {		/*jsr*/
    46   						i = (ival>= -128 && ival<=127) ? p1inlen-2 :
    47   							(ival>= -32768 && ival<=32767) ? p1inlen-4 : 0;
    48   						if (!i)
    49   							continue;
    50   						stbuf[2].itop.ptrw2 = bsrptr;	/*chng to bsr*/
    51   					}
    52   					else if(ival>= -128 && ival<=127) {
    53   						i = 2;		/*[vlh]was 4 for ival=2*/
    54   						if (!ival) stbuf[2].itop.ptrw2 = nopptr;
    55   					}
    56   					else
    57   						continue;
    58   					fixsyadr(i);
    59   					reduced =+ i;
1File: PASS1A.C                                                            Page       2
    60   					stbuf[1].itrl =- i;		/*reduced somewhat*/
    61   					if(!stbuf[1].itrl)
    62   						stbuf[1].itrl = -1;	/*ignore flag*/
    63   					oldpos=lseek(itfn,0L,1); /* Remember current position */
    64   					newpos= itoffset -
    65   						(stbuf[0].itrl*sizeof stbuf[0]);
    66   					if(lseek(itfn,newpos,0) < 0) {
    67   						rpterr("seek error on it file\n");
    68   						abort();
    69   					}
    70   					if(write(itfn,&stbuf[0],wsize) != wsize) {
    71   						rpterr("write error on it file\n");
    72   						abort();
    73   					}
    74   					lseek(itfn,oldpos,0);
    75   				}
    76   			}
    77   		}
    78   		else if(opcpt == endptr) {
    79   			savelc[TEXT] =- reduced;
    80   			return;
    81   		}
    82   	}
    83   }
    84    
    85   /* fix all symbol addresses that are text based and greater than loctr*/
    86   /*   fix means subtract 2 from them*/
    87   fixsyadr(al)
    88   {
    89   	register char **sx1, **sx2;
    90   	register l;
    91    
    92   	l = al;
    93   /* loop thru symbol initial reference table*/
    94   	for(sx1= sirt; sx1<&sirt[SZIRT-1]; sx1 =+ 2) {
    95   		if(*(sx2 = sx1+1)==0)		/* this chain is empty*/
    96   			continue;
    97    
    98   /* symbols on one chain*/
    99   		sx2 = *sx2;	/*first entry on this chain*/
   100   		while(1) {
   101   			if((sx2->flags&SYDF || sx2->flags&SYPC) && sx2->flags&SYRO &&
   102   			    sx2->vl1 > loctr)		/* [vlh] */
   103   				sx2->vl1 =- l;
   104   			if(sx2 == *sx1)	/*end of chain*/
   105   				break;
   106   			sx2 = sx2->tlnk;	/*next entry in chain*/
   107   		}
   108   	}
   109   }