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Digital-Research-Source-Code/CPM OPERATING SYSTEMS/CPM 68K/1.0X SOURCES/v102/as68/pass1a.lis
Sepp J Morris 31738079c4 Upload
Digital Research
2020-11-06 18:50:37 +01:00

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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 }