Possible bugs in ivm 0.33

[elnv]

Please, check the last changes in ivm 0.33, specially in the sigx implementation.
Some of our tests are failing. It seems related with the sign extension of words where the upper part are not filled with zeros (sigx1(0x1f00) is not always 0 in ivm 0.33, for example when this value comes from a memory load of size bigger than 1 byte).

At this stage of the development, we prefer continuing with the v0.32 version which is giving right results in all our test.

[ivar-rummelhoff]

You are right. I had not thought about that use case. sigx does not zero out any bits in v0.33. I can solve this with an extra AND for now, even though I suppose in most cases this will not be needed.