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1.1 root 1: #ifndef lint
2: static char sccsid[] = "@(#)expr.c 4.8 8/11/83";
3: #endif
4: /*
5: *
6: * UNIX debugger
7: *
8: */
9:
10: #include "defs.h"
11:
12: MSG BADSYM;
13: MSG BADVAR;
14: MSG BADKET;
15: MSG BADSYN;
16: MSG NOCFN;
17: MSG NOADR;
18: MSG BADLOC;
19:
20: ADDR lastframe;
21: ADDR savlastf;
22: ADDR savframe;
23: ADDR savpc;
24: ADDR callpc;
25:
26:
27:
28: CHAR *lp;
29: INT radix;
30: STRING errflg;
31: L_INT localval;
32: CHAR isymbol[1024];
33:
34: CHAR lastc,peekc;
35:
36: L_INT dot;
37: L_INT ditto;
38: INT dotinc;
39: L_INT var[];
40: L_INT expv;
41:
42:
43:
44:
45: expr(a)
46: { /* term | term dyadic expr | */
47: INT rc;
48: L_INT lhs;
49:
50: rdc(); lp--; rc=term(a);
51:
52: WHILE rc
53: DO lhs = expv;
54:
55: switch ((int)readchar()) {
56:
57: case '+':
58: term(a|1); expv += lhs; break;
59:
60: case '-':
61: term(a|1); expv = lhs - expv; break;
62:
63: case '#':
64: term(a|1); expv = round(lhs,expv); break;
65:
66: case '*':
67: term(a|1); expv *= lhs; break;
68:
69: case '%':
70: term(a|1); expv = lhs/expv; break;
71:
72: case '&':
73: term(a|1); expv &= lhs; break;
74:
75: case '|':
76: term(a|1); expv |= lhs; break;
77:
78: case ')':
79: IF (a&2)==0 THEN error(BADKET); FI
80:
81: default:
82: lp--;
83: return(rc);
84: }
85: OD
86: return(rc);
87: }
88:
89: term(a)
90: { /* item | monadic item | (expr) | */
91:
92: switch ((int)readchar()) {
93:
94: case '*':
95: term(a|1); expv=chkget(expv,DSP); return(1);
96:
97: case '@':
98: term(a|1); expv=chkget(expv,ISP); return(1);
99:
100: case '-':
101: term(a|1); expv = -expv; return(1);
102:
103: case '~':
104: term(a|1); expv = ~expv; return(1);
105:
106: case '#':
107: term(a|1); expv = !expv; return(1);
108:
109: case '(':
110: expr(2);
111: IF *lp!=')'
112: THEN error(BADSYN);
113: ELSE lp++; return(1);
114: FI
115:
116: default:
117: lp--;
118: return(item(a));
119: }
120: }
121:
122: item(a)
123: { /* name [ . local ] | number | . | ^ | <var | <register | 'x | | */
124: INT base, d;
125: CHAR savc;
126: BOOL hex;
127: L_INT frame;
128: register struct nlist *symp;
129: int regptr;
130:
131: hex=FALSE;
132:
133: readchar();
134: IF symchar(0)
135: THEN readsym();
136: IF lastc=='.'
137: THEN frame= *(ADDR *)(((ADDR)&u)+FP); lastframe=0;
138: callpc= *(ADDR *)(((ADDR)&u)+PC);
139: WHILE errflg==0
140: DO savpc=callpc;
141: findsym(callpc,ISYM);
142: IF eqsym(cursym->n_un.n_name,isymbol,'~')
143: THEN break;
144: FI
145: callpc=get(frame+16, DSP);
146: lastframe=frame;
147: frame=get(frame+12,DSP)&EVEN;
148: IF frame==0
149: THEN error(NOCFN);
150: FI
151: OD
152: savlastf=lastframe; savframe=frame;
153: readchar();
154: IF symchar(0)
155: THEN chkloc(expv=frame);
156: FI
157: ELIF (symp=lookup(isymbol))==0 THEN error(BADSYM);
158: ELSE expv = symp->n_value;
159: FI
160: lp--;
161:
162: ELIF getnum(readchar)
163: THEN ;
164: ELIF lastc=='.'
165: THEN readchar();
166: IF symchar(0)
167: THEN lastframe=savlastf; callpc=savpc;
168: chkloc(savframe);
169: ELSE expv=dot;
170: FI
171: lp--;
172:
173: ELIF lastc=='"'
174: THEN expv=ditto;
175:
176: ELIF lastc=='+'
177: THEN expv=inkdot(dotinc);
178:
179: ELIF lastc=='^'
180: THEN expv=inkdot(-dotinc);
181:
182: ELIF lastc=='<'
183: THEN savc=rdc();
184: IF regptr=getreg(savc)
185: THEN IF kcore THEN expv = *(int *)regptr;
186: ELSE expv= * (ADDR *)(((ADDR)&u)+regptr); FI
187: ELIF (base=varchk(savc)) != -1
188: THEN expv=var[base];
189: ELSE error(BADVAR);
190: FI
191:
192: ELIF lastc=='\''
193: THEN d=4; expv=0;
194: WHILE quotchar()
195: DO IF d--
196: THEN expv = (expv << 8) | lastc;
197: ELSE error(BADSYN);
198: FI
199: OD
200:
201: ELIF a
202: THEN error(NOADR);
203: ELSE lp--; return(0);
204: FI
205: return(1);
206: }
207:
208: /* service routines for expression reading */
209: getnum(rdf) int (*rdf)();
210: {
211: INT base,d,frpt;
212: BOOL hex;
213: UNION{REAL r; L_INT i;} real;
214: IF isdigit(lastc) ORF (hex=TRUE, lastc=='#' ANDF isxdigit((*rdf)()))
215: THEN expv = 0;
216: base = (hex ? 16 : radix);
217: WHILE (base>10 ? isxdigit(lastc) : isdigit(lastc))
218: DO expv = (base==16 ? expv<<4 : expv*base);
219: IF (d=convdig(lastc))>=base THEN error(BADSYN); FI
220: expv += d; (*rdf)();
221: IF expv==0
222: THEN IF (lastc=='x' ORF lastc=='X')
223: THEN hex=TRUE; base=16; (*rdf)();
224: ELIF (lastc=='t' ORF lastc=='T')
225: THEN hex=FALSE; base=10; (*rdf)();
226: ELIF (lastc=='o' ORF lastc=='O')
227: THEN hex=FALSE; base=8; (*rdf)();
228: FI
229: FI
230: OD
231: IF lastc=='.' ANDF (base==10 ORF expv==0) ANDF !hex
232: THEN real.r=expv; frpt=0; base=10;
233: WHILE isdigit((*rdf)())
234: DO real.r *= base; frpt++;
235: real.r += lastc-'0';
236: OD
237: WHILE frpt--
238: DO real.r /= base; OD
239: expv = real.i;
240: FI
241: peekc=lastc;
242: /* lp--; */
243: return(1);
244: ELSE return(0);
245: FI
246: }
247:
248: readsym()
249: {
250: REG char *p;
251:
252: p = isymbol;
253: REP IF p < &isymbol[sizeof(isymbol)-1]
254: THEN *p++ = lastc;
255: FI
256: readchar();
257: PER symchar(1) DONE
258: *p++ = 0;
259: }
260:
261: convdig(c)
262: CHAR c;
263: {
264: IF isdigit(c)
265: THEN return(c-'0');
266: ELIF isxdigit(c)
267: THEN return(c-'a'+10);
268: ELSE return(17);
269: FI
270: }
271:
272: symchar(dig)
273: {
274: IF lastc=='\\' THEN readchar(); return(TRUE); FI
275: return( isalpha(lastc) ORF lastc=='_' ORF dig ANDF isdigit(lastc) );
276: }
277:
278: varchk(name)
279: {
280: IF isdigit(name) THEN return(name-'0'); FI
281: IF isalpha(name) THEN return((name&037)-1+10); FI
282: return(-1);
283: }
284:
285: chkloc(frame)
286: L_INT frame;
287: {
288: readsym();
289: REP IF localsym(frame)==0 THEN error(BADLOC); FI
290: expv=localval;
291: PER !eqsym(cursym->n_un.n_name,isymbol,'~') DONE
292: }
293:
294: eqsym(s1, s2, c)
295: register char *s1, *s2;
296: {
297:
298: if (!strcmp(s1,s2))
299: return (1);
300: if (*s1 == c && !strcmp(s1+1, s2))
301: return (1);
302: return (0);
303: }
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