BSD 4_3 development

[unix-history] / usr / src / usr.bin / efl / field.c

#include "defs"



ptr mkfield(q)
register ptr q;
{
register ptr p;

if(!instruct)
       goto err;
else if(q->upperb == 0)
       dclerr("must have upper bound in field spcification", "");
else
       {
       p = ALLOC(fieldspec);
       p->tag = TFIELD;
       if(q->lowerb)
               {
               p->flbound = q->lowerb;
               p->frange = mknode(TAROP,OPPLUS,mknode(TAROP,OPMINUS,
                               q->upperb, cpexpr(q->lowerb)),
                               mkconst(TYINT,"1") );
               }
       else    {
               p->flbound = mkconst(TYINT,"1");
               p->frange = q->upperb;
               }
       p->frange = simple(RVAL,p->frange);
       if(p->frange->tag != TCONST)
               {
               dclerr("field range must be constant", "");
               cfree(p);
               goto err;
               }
       cfree(q);
       return(p);
       }

err:
       cfree(q);
       return( errnode() );
}





ptr extrfield(p)
register ptr p;
{
register ptr t;

t = p->vtypep;
p->vtype = TYINT;
p->vtypep = 0;

if(t->frshift)
       p = mknode(TAROP,OPSLASH, p, cpexpr(t->frshift));
if(t->fanymore)
       p = mkcall(builtin(TYINT, "mod"), arg2(p, cpexpr(t->frange)) );
p = mknode(TAROP,OPPLUS, p, cpexpr(t->flbound));
return(p);
}




ptr setfield(e)
ptr e;
{
ptr lp, rp;
register ptr f, p;
int subt;

lp = cpexpr(e->leftp);
rp = e->rightp;
subt = e->subtype;
f = lp->vtypep;
lp->vtype = TYINT;
lp->vtypep = 0;

if(subt==OPPLUS || subt==OPMINUS)
       {
       if(f->frshift)
               rp = mknode(TAROP,OPSTAR,rp,cpexpr(f->frshift));
       }
else    {
       if(subt != OPASGN)
               {
               rp = mknode(TAROP,subt, extrfield(cpexpr(e->leftp)), rp);
               subt = OPASGN;
               }
       rp = coerce(TYINT,rp);
       if(f->flbound)
               rp = simple(RVAL, mknode(TAROP,OPMINUS,rp,cpexpr(f->flbound)) );
       
       if(f->frshift==0)
               {
               if(f->fanymore)
                       {
                       p = mknode(TAROP,OPSLASH,cpexpr(lp),cpexpr(f->frange));
                       p->needpar = YES;
                       p = mknode(TAROP,OPSTAR,cpexpr(f->frange),p);
                       rp = mknode(TAROP,OPPLUS,p,rp);
                       }
               }
       else if(f->fanymore==0)
               {
               rp = mknode(TAROP,OPSTAR,cpexpr(f->frshift),rp);
               p = mkcall(builtin(TYINT,"mod"),
                       arg2(cpexpr(lp),cpexpr(f->frshift)) );
               rp = mknode(TAROP,OPPLUS, p,rp);
               }
       else    {
               p = mknode(TAROP,OPSLASH,cpexpr(lp),cpexpr(f->frshift));
               p = mkcall(builtin(TYINT,"mod"), 
                       arg2(p, cpexpr(f->frange)) );
               if( rp->tag!=TCONST || !equals(rp->leftp, "0") )
                       p = mknode(TAROP,OPMINUS, p, rp);
               rp = mknode(TAROP,OPSTAR, cpexpr(f->frshift), p);
               rp = mknode(TAROP,OPMINUS, cpexpr(lp), rp);
               }
       }
frexpr( simple(LVAL, mknode(TASGNOP,subt,lp,rp) ));
return(extrfield(e->leftp));
}