Upload

Digital Research

CPM OPERATING SYSTEMS/CPM 68K/1.0X SOURCES/v101/newas/pass1a.c

@@ -0,0 +1,109 @@
+/*
+	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*/
+		}
+	}
+}