Isaac Marino Bavaresco wrote:
> I may be wrong, but the C standard states that operands must be promoted
> "at least" to int, or to the type of the operand with highest precision.
>=20
> Also, the OP could use:
>=20
> #define S2_MIN  90u
> #define S2_MAX  125u
> #define S2_STEP  5u

I think there may be a more subtle issue going on here. The expression
(S2_MAX + S2_STEP) is evaluated at compile time, not run time, as we can se=
e
from the generated code.

My memory's a little hazy on this point, but doesn't the C standard state t=
hat
compile-time operations are to be done with the largest available size of e=
ach
type; i.e., longs for integers and doubles for floating-point?

It looks like the compiler in this case assumed that a compile-time constan=
t
calculation was to be done with signed char, which it then sign-extended to
16 bits for the run-time comparison. At the very least, this violates the
principle of "least surprise".

-- Dave Tweed
--=20
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