On 08.09.2014, at 19:44, David T. Lewis <lewis at mail.msen.com> wrote:

>> On 08.09.2014, at 18:28, Bert Freudenberg <bert at freudenbergs.de> wrote:
>> 
>>> https://github.com/bertfreudenberg/SqueakJS/commit/6d694d0733
>> 
>> Yikes. I just spotted another bug in that function. Can you see it, too?
> 
> I think it should be using an unsigned right shift like this:
> 
>   if ((shifted>>>shiftCount) === smallInt) return shifted;
> 
> Dave

No, "bitShift:" is supposed to be signed. This is my test if the result still fits in 32 bits, by reversing the shift. I *think* that part is correct ;)

E.g.
	-55 << 5 ==>  -1760
	-1760 >> 5 ==> -55

meaning we can use the result but

	-555555555 << 5 ==> -597908576
	-597908576 >> 5 ==> -18684643

so we cannot use the result because bits got dropped.

- Bert -

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