ISO/IEC JTC1/SC22/WG5 N1695

                       Bit Manipulation Features

                              Bill Long

Even though the BITS intrinsic data type is recommended for removal
from the Fortran 2008 draft standard, these related features are
recommended for retention or addition:


1) Retain these intrinsics beyond those in Fortran 2003:
   DSHIFTL
   DSHIFTR
   IALL
   IANY
   IPARITY
   LEADZ
   MASKL
   MASKR
   MERGE_BITS
   PARITY
   POPCNT
   POPPAR
   SHIFTA
   SHIFTL
   SHIFTR
   TRAILZ


2) Add four new intrinsic function that provide relational bit   
sequence comparisons of integer values based on their   
interpretation as bit sequences:

   BGE (I,J) - bits compare greater or equal
   BGT (I,J) - bits compare greater
   BLE (I,J) - bits compare less or equal
   BLT (I,J) - bits compare less

The result value is computed by the algorithm in paragraph 12 of   
7.1.5.6.1 Interpretation of relational intrinsic operations,   
[162:20-22], in N1678. Either or both of the arguments may be BOZ   
literal constants.


3) Retain the ability for formatted input and output of values of type   
REAL or COMPLEX using the Z, O, or B edit descriptors. 

Subclause 10.7.2.4 Bits editing, [285:1-24], in N1678 is the basis   
for this capability, with edits to restrict the allowed data types   
to integer, real, and complex (as a pair of reals), to change the   
description of how the objects are interpreted as bit sequences, and   
to change the subclause heading to "BOZ editing".


4) Retain BOZ literal constants as allowed arguments to these   
intrinsic functions:

   DSHIFTL (I,J,SHIFT)
   DSHIFTR (I,J,SHIFT)
   IAND (I,J)
   IEOR (I,J)
   IOR (I,J)
   MERGE_BITS (I,J,MASK)

For each of these functions, either, but not both, of the I or J   
arguments may be a BOZ literal constant. If I is of type integer   
and J is a BOZ literal constant, then the result of IAND (I,J) is   
equal to IAND (I, INT(J, KIND=KIND(I))), with corresponding results   
for the other functions. Similarly for J of type integer and I a   
BOZ literal constant.  In the case of MERGE_BITS, the MASK argument   
may also be a BOZ literal constant. The result value is computed as   
if the MASK were converted to type integer with the same effective   
kind type parameter as the I and J arguments.