tree 04551664899d82f874ae5cd22026a037ec786368
parent bc4b90122bd3e281f8086a83ef0616357c1f5d33
author Szabolcs Nagy <szabolcs.nagy@arm.com> 1530694469 +0100
committer Szabolcs Nagy <szabolcs.nagy@arm.com> 1530715521 +0100

Change the return type of converttoint and document the semantics

The roundtoint and converttoint internal functions are only called with small
values, so 32 bit result is enough for converttoint and it is a signed int
conversion so the natural return type is int32_t.

The original idea was to help the compiler keeping the result in uint64_t,
then it's clear that no sign extension is needed and there is no accidental
undefined or implementation defined signed int arithmetics.

But it turns out gcc does a good job with inlining so changing the type has
no overhead and the semantics of the conversion is less surprising this way.
Since we want to allow the asuint64 (x + 0x1.8p52) style conversion, the top
bits were never usable and the existing code ensures that only the bottom
32 bits of the conversion result are used.