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

#
/*
*
*      UNIX debugger
*
*/

#include "defs.h"


MSG             BADSYM;
MSG             BADVAR;
MSG             BADKET;
MSG             BADSYN;
MSG             NOCFN;
MSG             NOADR;
MSG             BADLOC;

SYMTAB          symbol;
INT             lastframe;
INT             savlastf;
L_INT           savframe;
INT             savpc;
INT             callpc;



CHAR            *lp;
INT             octal;
STRING          errflg;
L_INT           localval;
CHAR            isymbol[8];

CHAR            lastc;
POS             *endhdr;

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 (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--;
                       return(rc);
           }
       OD
       return(rc);
}

term(a)
{       /* item | monadic item | (expr) | */

       switch (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 '(':
                       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, frpt, regptr;
       CHAR            savc;
       BOOL            hex;
       L_INT           frame;
       UNION{REAL r; L_INT i;} real;
       SYMPTR          symp;

       hex=FALSE;

       readchar();
       IF symchar(0)
       THEN    readsym();
               IF lastc=='.'
               THEN    frame=endhdr[r5]&EVEN; lastframe=0; callpc=endhdr[pc];
                       WHILE errflg==0
                       DO  savpc=callpc;
                           findroutine(frame);
                           IF  eqsym(symbol.symc,isymbol,'~')
                           THEN break;
                           FI
                           lastframe=frame;
                           frame=get(frame,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=lookupsym(isymbol))==0 THEN error(BADSYM);
               ELSE expv = symp->symv;
               FI
               lp--;


       ELIF digit(lastc) ORF (hex=TRUE, lastc=='#' ANDF hexdigit(readchar()))
       THEN    expv = 0;
               base = (lastc == '0' ORF octal ? 8 : (hex ? 16 : 10));
               WHILE (hex ? hexdigit(lastc) : digit(lastc))
               DO  expv *= base;
                   IF (d=convdig(lastc))>=base THEN error(BADSYN); FI
                   expv += d; readchar();
                   IF expv==0 ANDF (lastc=='x' ORF lastc=='X')
                   THEN hex=TRUE; base=16; readchar();
                   FI
               OD
               IF lastc=='.' ANDF (base==10 ORF expv==0) ANDF !hex
               THEN    real.r=expv; frpt=0; base=10;
                       WHILE digit(readchar())
                       DO      real.r *= base; frpt++;
                               real.r += lastc-'0';
                       OD
                       WHILE frpt--
                       DO      real.r /= base; OD
                       expv = real.i;
               FI
               lp--;

       ELIF lastc=='.'
       THEN    readchar();
               IF symchar(0)
               THEN    lastframe=savlastf; callpc=savpc; findroutine(savframe);
                       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=endhdr[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 */

readsym()
{
       REG char        *p;

       p = isymbol;
       REP IF p < &isymbol[8]
           THEN *p++ = lastc;
           FI
           readchar();
       PER symchar(1) DONE
       WHILE p < &isymbol[8] DO *p++ = 0; OD
}

SYMPTR  lookupsym(symstr)
STRING  symstr;
{
       SYMPTR          symp;
       symset();
       WHILE (symp=symget())
       DO IF (symp->symf&SYMCHK)==symp->symf
          ANDF eqsym(symp->symc, symstr,'_')
           THEN return(symp);
           FI
       OD
       return(0);
}

hexdigit(c)
CHAR c;
{       return((c>='0' ANDF c<='9') ORF (c>='a' ANDF c<='f'));
}

convdig(c)
CHAR c;
{
       IF digit(c)
       THEN    return(c-'0');
       ELIF hexdigit(c)
       THEN    return(c-'a'+10);
       ELSE    return(17);
       FI
}

digit(c) char c;        {return(c>='0' ANDF c<='9');}

letter(c) char c;       {return(c>='a' ANDF c<='z' ORF c>='A' ANDF c<='Z');}

symchar(dig)
{
       IF lastc=='\\' THEN readchar(); return(TRUE); FI
       return( letter(lastc) ORF lastc=='_' ORF dig ANDF digit(lastc) );
}

varchk(name)
{
       IF digit(name) THEN return(name-'0'); FI
       IF letter(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(symbol.symc,isymbol,'~') DONE
}

eqsym(s1, s2, c)
REG STRING      s1, s2;
CHAR            c;
{
       IF eqstr(s1,s2)
       THEN    return(TRUE);
       ELIF *s1==c
       THEN    CHAR            s3[8];
               REG INT         i;

               s3[0]=c;
               FOR i=1; i<8; i++
               DO s3[i] = *s2++; OD

               return(eqstr(s1,s3));
       FI
}