To: J3                                                        08-118r2
From: Malcolm Cohen
Subject: UTI 149, INT/REAL with boz argument
Date: 2008 February 13

1. Introduction

Too much of INT(boz) has become processor dependent (more than in F2003).
In addition, the description needs to be modified to take into account the
padding and truncation of the boz argument that might take place.  The
padding and truncation modification is also needed for REAL.

2. Further considerations

The literal meaning of "if its value were the bit pattern" is "if false".
False implies anything, so it specifies nothing.

Also, truncating a bit sequence to fit it into the result is likely
going to produce an unexpected and inadvertant value.  There are
valid uses for INTEGER but it is surely a mistake for REAL, and
should be disallowed.

Also, padding a bit sequence to fit it into the result is only likely to be
harmless for INT (even there it will be harmful if the user was intending
to set the most significant bit and miscounted the number of digits).
We should consider disallowing this as well.

Fortran 2003 did not establish interpretations for these cases so we have
a free hand in ruling out obvious mistakes.


3. Edits to J3/08-007:

In 13.3.3, index "padding" and "truncation" as definitions.

[345:31+] New paragraph with constraint:
  "C13aa If a \si{boz-literal-constant} is truncated as an argument to the
         intrinsic function REAL, the discarded bits shall all be zero."
{Prevents user initialization mistakes.}

[390:33-36] Replace case (iv) of the Result Value section of 13.7.81
            INT(A [,KIND]) with
  "If A is a \si{boz-literal-constant}, the value of the result is
   the value whose bit sequence according to the model in
   \ref{D13:Bit model} is the same as that of A as modified by
   \mindex*{padding} or \mindex*{truncation} according to
   \ref{D13:Bit sequences as arguments to INT and REAL}.  The
   interpretation of a bit sequence whose most significant bit is 1 is
   processor dependent."

[416:24-27] Replace case(iii) of the Result Value section of 13.7.136
            REAL(A [,KIND]) with
  "If A is a \si{boz-literal-constant}, the value of the result is the
   value whose internal representation as a bit sequence is the same as
   that of A as modified by \mindex*{padding} or \mindex*{truncation}
   according to \ref{D13:Bit sequences as arguments to INT and REAL}.  The
   interpretation of the bit sequence is processor dependent."

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