const
  up=true;
  down=false;
  topint=32767;                   { max allowed integer value }
  strnglen=600;   { max length of strings to represent hreals }
  exmax=10000;          { max exponent, smaller than topint/2 }
  zdim=80;                      { a number between 79 and 100 }

type
  longstring=varying[strnglen] of char;
  hint=array[0..hdim] of integer;
  hreal=record
    si: integer;                                       { sign }
    ma: hint;                                      { mantissa }
    ex: integer;                       { exponent, base 10000 }
  end;
  scalar=record
    l: hreal;                                   { lower bound }
    u: hreal;                                   { upper bound }
  end;
  vector=array[0..vdim] of scalar;
  ltuple=array[0..lmax] of scalar;
  matrix=array[0..lmax,0..lmax] of scalar;
  vtuple=array[0..lmax] of vector;
  zeros=array[0..zdim] of scalar;

var
  trunc,underflow,overflow: boolean;
  e: array[0..edim] of integer;               { used by rquot }
  sone,stwo,shalf: scalar;              { the numbers 1,2,1/2 }