J3/16-164r1 To: J3 From: Van Snyder and Robert Corbett Subject: IEEE_REM Date: 2016 February 10 Reference: 16-007, 16-141 General: For the arithmetic functions with two arguments, e.g., IEEE_REM, are arguments with different radices supported? It should either be stated explicitly, or denied explicitly. /JOR: The two and three argument IEEE arithmetic functions that are new in Fortran 2015 require homogeneous operands. The IEEE arithmetic functions carried over from Fortran 2008, other than IEEE_REM, have well-defined semantics for arguments with different radices. IEEE_REM does not have well-defined semantics for some combinations of arguments of different radices. The definition of IEEE_REM given in 16-007 requires the result to be exact. For some combinations of mixed radix arguments, no exact result is possible. ISO/IEC 60559:2011 requires the operands of the remainder operation to be homogeneous. Although we envisaged supporting non-binary radices for IEEE kinds in Fortran 2008, we did not actually manage to permit them; so technically, there is no incompatibility. Edits are provided to require the arguments of IEEE_REM to have the same radix. Edits to 16-007 --------------- [xvii, Introduction] Insert in the item that lists changes to the IEEE modules: "The function IEEE_REM now requires its arguments to have the same radix." [443:3, 14.11.31p4] Replace "the value false." with "the value false, or if RADIX(X) is not equal to RADIX(Y)."