1 # 2 /* 3 * 4 * UNIX debugger 5 * 6 */ 7 8 #include "defs.h" 9 static char sccsid[] = "@(#)expr.c 4.1 05/14/81"; 10 11 MSG BADSYM; 12 MSG BADVAR; 13 MSG BADKET; 14 MSG BADSYN; 15 MSG NOCFN; 16 MSG NOADR; 17 MSG BADLOC; 18 19 ADDR lastframe; 20 ADDR savlastf; 21 ADDR savframe; 22 ADDR savpc; 23 ADDR callpc; 24 25 26 27 CHAR *lp; 28 INT radix; 29 STRING errflg; 30 L_INT localval; 31 CHAR isymbol[BSIZE]; 32 33 CHAR lastc,peekc; 34 35 L_INT dot; 36 L_INT ditto; 37 INT dotinc; 38 L_INT var[]; 39 L_INT expv; 40 41 42 43 44 expr(a) 45 { /* term | term dyadic expr | */ 46 INT rc; 47 L_INT lhs; 48 49 rdc(); lp--; rc=term(a); 50 51 WHILE rc 52 DO lhs = expv; 53 54 switch ((int)readchar()) { 55 56 case '+': 57 term(a|1); expv += lhs; break; 58 59 case '-': 60 term(a|1); expv = lhs - expv; break; 61 62 case '#': 63 term(a|1); expv = round(lhs,expv); break; 64 65 case '*': 66 term(a|1); expv *= lhs; break; 67 68 case '%': 69 term(a|1); expv = lhs/expv; break; 70 71 case '&': 72 term(a|1); expv &= lhs; break; 73 74 case '|': 75 term(a|1); expv |= lhs; break; 76 77 case ')': 78 IF (a&2)==0 THEN error(BADKET); FI 79 80 default: 81 lp--; 82 return rc); 83 } 84 OD 85 return(rc); 86 } 87 88 term(a) 89 { /* item | monadic item | (expr) | */ 90 91 switch ((int)readchar()) { 92 93 case '*': 94 term(a|1); expv=chkget(expv,DSP); return(1); 95 96 case '@': 97 term(a|1); expv=chkget(expv,ISP); return(1); 98 99 case '-': 100 term(a|1); expv = -expv; return(1); 101 102 case '~': 103 term(a|1); expv = ~expv; return(1); 104 105 case '#': 106 term(a|1); expv = !expv; return(1); 107 108 case '(': 109 expr(2); 110 IF *lp!=')' 111 THEN error(BADSYN); 112 ELSE lp++; return(1); 113 FI 114 115 default: 116 lp--; 117 return(item(a)); 118 } 119 } 120 121 item(a) 122 { /* name [ . local ] | number | . | ^ | <var | <register | 'x | | */ 123 INT base, d, regptr; 124 CHAR savc; 125 BOOL hex; 126 L_INT frame; 127 register struct nlist *symp; 128 129 hex=FALSE; 130 131 readchar(); 132 IF symchar(0) 133 THEN readsym(); 134 IF lastc=='.' 135 THEN frame= *(ADDR *)(((ADDR)&u)+FP); lastframe=0; 136 callpc= *(ADDR *)(((ADDR)&u)+PC); 137 WHILE errflg==0 138 DO savpc=callpc; 139 findsym(callpc,ISYM); 140 IF eqsym(cursym->n_un.n_name,isymbol,'~') 141 THEN break; 142 FI 143 callpc=get(frame+16, DSP); 144 lastframe=frame; 145 frame=get(frame+12,DSP)&EVEN; 146 IF frame==0 147 THEN error(NOCFN); 148 FI 149 OD 150 savlastf=lastframe; savframe=frame; 151 readchar(); 152 IF symchar(0) 153 THEN chkloc(expv=frame); 154 FI 155 ELIF (symp=lookup(isymbol))==0 THEN error(BADSYM); 156 ELSE expv = symp->n_value; 157 FI 158 lp--; 159 160 161 ELIF getnum(readchar) 162 THEN ; 163 ELIF lastc=='.' 164 THEN readchar(); 165 IF symchar(0) 166 THEN lastframe=savlastf; callpc=savpc; 167 chkloc(savframe); 168 ELSE expv=dot; 169 FI 170 lp--; 171 172 ELIF lastc=='"' 173 THEN expv=ditto; 174 175 ELIF lastc=='+' 176 THEN expv=inkdot(dotinc); 177 178 ELIF lastc=='^' 179 THEN expv=inkdot(-dotinc); 180 181 ELIF lastc=='<' 182 THEN savc=rdc(); 183 IF regptr=getreg(savc) 184 THEN expv= * (ADDR *)(((ADDR)&u)+regptr); 185 ELIF (base=varchk(savc)) != -1 186 THEN expv=var[base]; 187 ELSE error(BADVAR); 188 FI 189 190 ELIF lastc=='\'' 191 THEN d=4; expv=0; 192 WHILE quotchar() 193 DO IF d-- 194 THEN IF d==1 THEN expv <<=16; FI 195 expv |= ((d&1)?lastc:lastc<<8); 196 ELSE error(BADSYN); 197 FI 198 OD 199 200 ELIF a 201 THEN error(NOADR); 202 ELSE lp--; return(0); 203 FI 204 return(1); 205 } 206 207 /* service routines for expression reading */ 208 getnum(rdf) int (*rdf)(); 209 { 210 INT base,d,frpt; 211 BOOL hex; 212 UNION{REAL r; L_INT i;} real; 213 IF isdigit(lastc) ORF (hex=TRUE, lastc=='#' ANDF isxdigit((*rdf)())) 214 THEN expv = 0; 215 base = (hex ? 16 : radix); 216 WHILE (base>10 ? isxdigit(lastc) : isdigit(lastc)) 217 DO expv = (base==16 ? expv<<4 : expv*base); 218 IF (d=convdig(lastc))>=base THEN error(BADSYN); FI 219 expv += d; (*rdf)(); 220 IF expv==0 221 THEN IF (lastc=='x' ORF lastc=='X') 222 THEN hex=TRUE; base=16; (*rdf)(); 223 ELIF (lastc=='t' ORF lastc=='T') 224 THEN hex=FALSE; base=10; (*rdf)(); 225 ELIF (lastc=='o' ORF lastc=='O') 226 THEN hex=FALSE; base=8; (*rdf)(); 227 FI 228 FI 229 OD 230 IF lastc=='.' ANDF (base==10 ORF expv==0) ANDF !hex 231 THEN real.r=expv; frpt=0; base=10; 232 WHILE isdigit((*rdf)()) 233 DO real.r *= base; frpt++; 234 real.r += lastc-'0'; 235 OD 236 WHILE frpt-- 237 DO real.r /= base; OD 238 expv = real.i; 239 FI 240 peekc=lastc; 241 /* lp--; */ 242 return(1); 243 ELSE return(0); 244 FI 245 } 246 247 readsym() 248 { 249 REG char *p; 250 251 p = isymbol; 252 REP IF p < &isymbol[sizeof(isymbol)-1] 253 THEN *p++ = lastc; 254 FI 255 readchar(); 256 PER symchar(1) DONE 257 *p++ = 0; 258 } 259 260 convdig(c) 261 CHAR c; 262 { 263 IF isdigit(c) 264 THEN return(c-'0'); 265 ELIF isxdigit(c) 266 THEN return(c-'a'+10); 267 ELSE return(17); 268 FI 269 } 270 271 symchar(dig) 272 { 273 IF lastc=='\\' THEN readchar(); return(TRUE); FI 274 return( isalpha(lastc) ORF lastc=='_' ORF dig ANDF isdigit(lastc) ); 275 } 276 277 varchk(name) 278 { 279 IF isdigit(name) THEN return(name-'0'); FI 280 IF isalpha(name) THEN return((name&037)-1+10); FI 281 return(-1); 282 } 283 284 chkloc(frame) 285 L_INT frame; 286 { 287 readsym(); 288 REP IF localsym(frame)==0 THEN error(BADLOC); FI 289 expv=localval; 290 PER !eqsym(cursym->n_un.n_name,isymbol,'~') DONE 291 } 292 293 eqsym(s1, s2, c) 294 register char *s1, *s2; 295 { 296 297 if (!strcmp(s1,s2)) 298 return (1); 299 if (*s1 == c && !strcmp(s1+1, s2)) 300 return (1); 301 return (0); 302 } 303