import "io"
import "os1"

manifest
{ ptn_bits = selector 10 : 22,
  pn_bits = selector 11 : 11,
  offset_bits = selector 11 : 0 }

manifest
{ iv_none = 0,        iv_memory = 1,      iv_pagefault = 2,   iv_unimpop = 3,
  iv_halt = 4,        iv_divzero = 5,     iv_unwrop = 6,      iv_timer = 7,
  iv_privop = 8,      iv_keybd = 9,       iv_badcall = 10,    iv_pagepriv = 11,
  iv_debug = 12,      iv_intrfault = 13 }


let ihandle_pf(intcode, address, info, pc) be
{
  let ptn = ptn_bits from address,
       pn = pn_bits from address,
      off = offset_bits from address;

  let pt_physaddr = pgdir_va ! ptn >> 11;

  out("Page Fault for %08x: PT:%d, PN:%d, OFF:%d\n", address, ptn, pn, off);
  out("PC was %08x = %d\n", pc, pc);
  out("relevant page table is phys page %d\n", pt_physaddr);

  ptspec_va ! spec_p1e := (pt_physaddr << 11) bitor 1;
  p1_va ! pn := (13 << 11) bitor 1;

  ireturn 
}


let start() be
{ let addr = 0x80003210, n;

  assembly
  { getsr r1, $flags
    cbit      $ip
    setsr r1, $flags }

  intvec_va ! iv_pagefault := ihandle_pf;

  outs("number? ");
  n := inno();
  outs("storing...");
  ! addr := n;
  outs("...stored\n");
  out("%d\n", ! addr) }