fix per rob pike

[unix-history] / usr / src / old / adb / adb.vax / expr.c

#
/*
*
*      UNIX debugger
*
*/

#include "defs.h"
static  char sccsid[] = "@(#)expr.c 4.5 %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[1024];

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(1);

                   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;
       CHAR            savc;
       BOOL            hex;
       L_INT           frame;
       register struct nlist *symp;
       int regptr;

       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    IF kcore THEN expv = *(int *)regptr;
                       ELSE expv= * (ADDR *)(((ADDR)&u)+regptr); FI
               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 expv = (expv << 8) | lastc;
                   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);
}