On 9/9/22 10:43 AM, John wrote:
>
> On most machines -1-huge(0) is representable, but should
> OUT_OF_RANGE(-1-huge(0)) return .FALSE.?
>
> Since how a negative integer is represented at the bit level is processor
> dependent, should the range (for example) of a 1-byte integer be treated
> as -127 to 127 or -128 to 127?
[...]

You may already know this, but this is the example in the f2018 standard:

Examples. If INT8 is the kind value for an 8-bit binary integer type,
OUT_OF_RANGE (-128.5, 0_INT8) will have the value false and
OUT_OF_RANGE (-128.5, 0_INT8, .TRUE.) will have the value true.

The first case is rounded toward zero, -128, while the second is rounded
the other way to -129.

The description of the function only refers to whether the value is
representable, so I think -128 is intended to satisfy that. This is not
the same as the fortran integer model, which does not include the value
-128. The integer model is defined in Section 16.4.

$.02 -Ron Shepard

In the case of the example if the first argument was a one byte integer of value -128 ABS would be problematic because it would be trying to return 128, which is out of bounds, but for most other types or if you have a larger type to promote it to with INT it would work. For the time being we made a function called OUT_OF_MODEL_RANGE that does what he wants. After going through the standard again with the references sited here in hand it does look like OUT_OF_RANGE is determining if a value is represent-able, not that it fits the model, as you note -- so no bug reports.