Wrong result for ADD operation: (-0) + (-0) returns +0 instead of (-0)

[ntuszynski]

Hello, FPU module computes wrong results for the ADD operation of (-0) and (-0). The returned result is (+0) instead of (-0) according to the IEEE standard BR, Nicolae

[ntuszynski]

Same is valid for SUB operation

[tovine]

This might be a similar problem to https://github.com/pulp-platform/fpu/issues/5 - it seems that there have been done some aggressive optimizations.