bit manipulation functions

[Steve Kargl]

Gang,

It seems that our bit manipulation functions are more
restrictive than implied by the language of the standard 
(where I only have a PDF of the May 2004 working draft of
the newest standard).  Anyway, the language for IBSET is

------------------------------------------------------
13.7.49   IBSET(I, POS)

  Description.  Sets one bit to one.

  Class.        Elemental function.

  Arguments.
    I           shall be of type integer.
    POS         shall be of type integer. It shall be nonnegative and 
                less than BIT_SIZE(I).

  Result Characteristics.  Same as I.

  Result Value.  The result has the value of the sequence of bits of 
                 I, except that bit POS is one.
------------------------------------------------------

Note I and POS "shall be of type integer".  The kind parameter is
not specified.  We currently restrict POS to default integer
kind with an implied restriction of I to default integer kind.
The restriction is in check.c

try
gfc_check_ibset (gfc_expr * i, gfc_expr * pos)
{

  if (type_check (i, 0, BT_INTEGER) == FAILURE
      || type_check (pos, 1, BT_INTEGER) == FAILURE
      || kind_value_check (pos, 1, gfc_default_integer_kind) == FAILURE)
    return FAILURE;

  return SUCCESS;
}

If I remove the kind_value_check() from the above.  The attached
program produces the following output:
kargl[205] ./bits
  8 16 32 64
  6  6  6  6
 20 20 20 20
   12 4108 4108 4108
This agrees with both G77 and NAG's Fortran 95 compiler.  So, do
we want to loosen the restrictions?

-- 
Steve
-------------- next part --------------
      program bits

      integer b1, b2, b4, b8
      integer*1 i1, j1
      integer*2 i2, j2
      integer*4 i4, j4
      integer*8 i8, j8

      b1 = bit_size(i1)
      b2 = bit_size(i2)
      b4 = bit_size(i4)
      b8 = bit_size(i8)
      write(*,'(4I3)') b1, b2, b4, b8

      i1 = 2
      j1 = ibset(i1,i1)
      i2 = 2
      j2 = ibset(i2,i2)
      i4 = 2
      j4 = ibset(i4,i4)
      i8 = 2
      j8 = ibset(i8,i8)
      write(*,'(4I3)') j1, j2, j4, j8

      i1 = 4
      j1 = ibset(i1,i1)
      i2 = 4
      j2 = ibset(i2,i1)
      i4 = 4
      j4 = ibset(i4,i1)
      i8 = 4
      j8 = ibset(i8,i1)
      write(*,'(4I3)') j1, j2, j4, j8

      i1 = 12
      j1 = ibset(i1,i1)
      i2 = 12
      j2 = ibset(i2,i1)
      i4 = 12
      j4 = ibset(i4,i1)
      i8 = 12
      j8 = ibset(i8,i1)
      write(*,'(4I5)') j1, j2, j4, j8

      end