Double precision floating point unit is a FPU implementation different
from the FPU2000 in the following ways:
- it may be configured with only single or with both single and double
precision operations support;
- it may be configured with division and square root opcodes;
- FSR register accumulates inValid, division by Zero, Overflow,
Underflow and Inexact result flags of operations;
- QNaNs and SNaNs are handled properly;
- NaN propagation rules are different.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
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