+#
+/*
+ *
+ * UNIX debugger
+ *
+ */
+
+#include "defs.h"
+static char sccsid[] = "@(#)expr.c.bad 4.1 %G%";
+
+MSG BADSYM;
+MSG BADVAR;
+MSG BADKET;
+MSG BADSYN;
+MSG NOCFN;
+MSG NOADR;
+MSG BADLOC;
+
+ADDR lastframe;
+ADDR savlastf;
+ADDR savframe;
+ADDR savpc;
+ADDR callpc;
+
+
+
+CHAR *lp;
+INT radix;
+STRING errflg;
+L_INT localval;
+CHAR isymbol[BSIZE];
+
+CHAR lastc,peekc;
+
+L_INT dot;
+L_INT ditto;
+INT dotinc;
+L_INT var[];
+L_INT expv;
+
+
+
+
+expr(a)
+{ /* term | term dyadic expr | */
+ INT rc;
+ L_INT lhs;
+
+ rdc(); lp--; rc=term(a);
+
+ WHILE rc
+ DO lhs = expv;
+
+ switch ((int)readchar()) {
+
+ case '+':
+ term(a|1); expv += lhs; break;
+
+ case '-':
+ term(a|1); expv = lhs - expv; break;
+
+ case '#':
+ term(a|1); expv = round(lhs,expv); break;
+
+ case '*':
+ term(a|1); expv *= lhs; break;
+
+ case '%':
+ term(a|1); expv = lhs/expv; break;
+
+ case '&':
+ term(a|1); expv &= lhs; break;
+
+ case '|':
+ term(a|1); expv |= lhs; break;
+
+ case ')':
+ IF (a&2)==0 THEN error(BADKET); FI
+
+ default:
+ lp--;
+ \19return rc);
+ }
+ OD
+ return(rc);
+}
+
+term(a)
+{ /* item | monadic item | (expr) | */
+
+ switch ((int)readchar()) {
+
+ case '*':
+ term(a|1); expv=chkget(expv,DSP); return(1);
+
+ case '@':
+ term(a|1); expv=chkget(expv,ISP); return(1);
+
+ case '-':
+ term(a|1); expv = -expv; return(1);
+
+ case '~':
+ term(a|1); expv = ~expv; return¨±);
+
+ case '#':
+ term(a|1); expv = !expv; return(1);
+
+ case '(':
+ expr(2);
+ IF *lp!=')'
+ THEN error(BADSYN);
+ ELSE lp++; return(1);
+ FI
+
+ default:
+ lp--;
+ return(item(a));
+ }
+}
+
+item(a)
+{ /* name [ . local ] | number | . | ^ | <var | <register | 'x | | */
+ INT base, d, regptr;
+ CHAR savc;
+ BOOL hex;
+ L_INT frame;
+ register struct nlist *symp;
+
+ hex=FALSE;
+
+ readchar();
+ IF symchar(0)
+ THEN readsym();
+ IF lastc=='.'
+ THEN frame= *(ADDR *)(((ADDR)&u)+FP); lastframe=0;
+ callpc= *(ADDR *)(((ADDR)&u)+PC);
+ WHILE errflg==0
+ DO savpc=callpc;
+ findsym(callpc,ISYM);
+ IF eqsym(cursym->n_un.n_name,isymbol,'~')
+ THEN break;
+ FI
+ callpc=get(frame+16, DSP);
+ lastframe=frame;
+ frame=get(frame+12,DSP)&EVEN;
+ IF frame==0
+ THEN error(NOCFN);
+ FI
+ OD
+ savlastf=lastframe; savframe=frame;
+ readchar();
+ IF symchar(0)
+ THEN chkloc(expv=frame);
+ FI
+ ELIF (symp=lookup(isymbol))==0 THEN error(BADSYM);
+ ELSE expv = symp->n_value;
+ FI
+ lp--;
+
+
+ ELIF getnum(readchar)
+ THEN ;
+ ELIF lastc=='.'
+ THEN readchar();
+ IF symchar(0)
+ THEN lastframe=savlastf; callpc=savpc;
+ chkloc(savframe);
+ ELSE expv=dot;
+ FI
+ lp--;
+
+ ELIF lastc=='"'
+ THEN expv=ditto;
+
+ ELIF lastc=='+'
+ THEN expv=inkdot(dotinc);
+
+ ELIF lastc=='^'
+ THEN expv=inkdot(-dotinc);
+
+ ELIF lastc=='<'
+ THEN savc=rdc();
+ IF regptr=getreg(savc)
+ THEN expv= * (ADDR *)(((ADDR)&u)+regptr);
+ ELIF (base=varchk(savc)) != -1
+ THEN expv=var[base];
+ ELSE error(BADVAR);
+ FI
+
+ ELIF lastc=='\''
+ THEN d=4; expv=0;
+ WHILE quotchar()
+ DO IF d--
+ THEN IF d==1 THEN expv <<=16; FI
+ expv |= ((d&1)?lastc:lastc<<8);
+ ELSE error(BADSYN);
+ FI
+ OD
+
+ ELIF a
+ THEN error(NOADR);
+ ELSE lp--; return(0);
+ FI
+ return(1);
+}
+
+/* service routines for expression reading */
+getnum(rdf) int (*rdf)();
+{
+ INT base,d,frpt;
+ BOOL hex;
+ UNION{REAL r; L_INT i;} real;
+ IF isdigit(lastc) ORF (hex=TRUE, lastc=='#' ANDF isxdigit((*rdf)()))
+ THEN expv = 0;
+ base = (hex ? 16 : radix);
+ WHILE (base>10 ? isxdigit(lastc) : isdigit(lastc))
+ DO expv = (base==16 ? expv<<4 : expv*base);
+ IF (d=convdig(lastc))>=base THEN error(BADSYN); FI
+ expv += d; (*rdf)();
+ IF expv==0
+ THEN IF (lastc=='x' ORF lastc=='X')
+ THEN hex=TRUE; base=16; (*rdf)();
+ ELIF (lastc=='t' ORF lastc=='T')
+ THEN hex=FALSE; base=10; (*rdf)();
+ ELIF (lastc=='o' ORF lastc=='O')
+ THEN hex=FALSE; base=8; (*rdf)();
+ FI
+ FI
+ OD
+ IF lastc=='.' ANDF (base==10 ORF expv==0) ANDF !hex
+ THEN real.r=expv; frpt=0; base=10;
+ WHILE isdigit((*rdf)())
+ DO real.r *= base; frpt++;
+ real.r += lastc-'0';
+ OD
+ WHILE frpt--
+ DO real.r /= base; OD
+ expv = real.i;
+ FI
+ peekc=lastc;
+/* lp--; */
+ return(1);
+ ELSE return(0);
+ FI
+}
+
+readsym()
+{
+ REG char *p;
+
+ p = isymbol;
+ REP IF p < &isymbol[sizeof(isymbol)-1]
+ THEN *p++ = lastc;
+ FI
+ readchar();
+ PER symchar(1) DONE
+ *p++ = 0;
+}
+
+convdig(c)
+CHAR c;
+{
+ IF isdigit(c)
+ THEN return(c-'0');
+ ELIF isxdigit(c)
+ THEN return(c-'a'+10);
+ ELSE return(17);
+ FI
+}
+
+symchar(dig)
+{
+ IF lastc=='\\' THEN readchar(); return(TRUE); FI
+ return( isalpha(lastc) ORF lastc=='_' ORF dig ANDF isdigit(lastc) );
+}
+
+varchk(name)
+{
+ IF isdigit(name) THEN return(name-'0'); FI
+ IF isalpha(name) THEN return((name&037)-1+10); FI
+ return(-1);
+}
+
+chkloc(frame)
+L_INT frame;
+{
+ readsym();
+ REP IF localsym(frame)==0 THEN error(BADLOC); FI
+ expv=localval;
+ PER !eqsym(cursym->n_un.n_name,isymbol,'~') DONE
+}
+
+eqsym(s1, s2, c)
+ register char *s1, *s2;
+{
+
+ if (!strcmp(s1,s2))
+ return (1);
+ if (*s1 == c && !strcmp(s1+1, s2))
+ return (1);
+ return (0);
+}
projects / unix-history / commitdiff