BSD 4_3_Net_2 release

[unix-history] / usr / src / usr.bin / pascal / pdx / runtime / address.c

/*-
* Copyright (c) 1980 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*      This product includes software developed by the University of
*      California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#ifndef lint
static char sccsid[] = "@(#)address.c   5.2 (Berkeley) 4/16/91";
#endif /* not lint */

/*
* Some machine and runtime dependent manipulation of a symbol.
*/

#include "defs.h"
#include "runtime.h"
#include "sym.h"
#include "machine.h"
#include "process.h"
#include "object.h"
#include "mappings.h"
#include "sym/classes.h"
#include "frame.rep"
#include "sym/sym.rep"

/*
* Calculate the address of a symbol.
* If frame is not NIL, then it is the frame associated with the
* activation in which the symbol we're interested in is defined.
*/

ADDRESS address(s, frame)
register SYM *s;
FRAME *frame;
{
   SYM *f;
   FRAME *frp;
   ADDRESS r, *dp, *disp;
   short offs;

   f = s->func;
   if (s->class == FVAR) {
       offs = f->symvalue.offset;
   } else {
       offs = s->symvalue.offset;
   }
   if (f == program) {
       r = (ADDRESS) dispval(MAINBLK) + offs;
   } else if (f == curfunc && frame == NIL) {
       dp = curdp();
       disp = contents(dp);
       r = (ADDRESS) disp + offs;
   } else {
       if (frame == NIL) {
           frp = findframe(s->func);
           if (frp == NIL) {
               panic("address: findframe returned NIL");
           }
       } else {
           frp = frame;
       }
       r = stkaddr(frp, s->blkno) + offs;
   }
   return r;
}

/*
* The next three routines assume the procedure entry code is
*
*      f:  tra4    A
*          ...
*      A:  beg
*      B:  <code for first line>
*
* Pi gives f, we compute and store A with "findbeginning(f)",
* (retrieved by "codeloc(f)"), B is computed by "firstline(f)".
*
* The procedure "runtofirst" assumes you're at A and want to step to B.
* It should be changed to a nop if A is equal to B.
*/

/*
* Find the beginning of a procedure or function.  This is a destructive
* routine, it changes the value associated with the procedure symbol.
* Should only be called once per symbol.
*/

findbeginning(f)
SYM *f;
{
   f->symvalue.funcv.codeloc = nextaddr(f->symvalue.funcv.codeloc, FALSE);
}

/*
* Find the object code associated with the first line of a block.
*/

ADDRESS firstline(f)
SYM *f;
{
   ADDRESS addr;

   addr = codeloc(f);
   while (linelookup(addr) == 0) {
       if (isendofproc(addr)) {
           return -1;
       }
       addr = nextaddr(addr, FALSE);
   }
   return addr;
}

/*
* Catcher drops strike three ...
*/

runtofirst()
{
   stepto(firstline(curfunc));
}

/*
* Calculate the address of the last line in the program.
* This is assumed to be at the physical end.
*/

ADDRESS lastaddr()
{
   if (objsize == 0) {
       panic("lastaddr: objsize = 0!");
   }
   return(objsize - sizeof(short));
}