This enables rocket-chip to upgrade to 2.12

* add small div/sqrt unit

* Chisel3 doesn't permit mixed UInt/SInt muxing/assignment

* Fix control bug in DivSqrtRecFN_small

After an uncommon-case operation, outValid would remain high until
another inValid was presented, instead of going low after one cycle.

integers.

'RoundAnyRawFNToRecFN'.

integer values in module 'DivSqrtRecF64_mulAddZ31'.

of 'var'.

If you use a 'val' in an object, it is only run once.  This makes the first
elaboration of a Module different from subsequent elaboration runs, breaking
deduplication.

known as jamming).

rounding mode so that it rounds to minimum magnitude instead, same as
'minMag'.

Newer releases of berkeley-softfloat-3 allow users to set the
SPECIALIZE_TYPE variable without applying a patch.  This commit removes
the patch and sets the variable on the make commandline instead.

Note that there's no dependency checking for berkeley-softfloat-3 when
checked out locally, so you might have to "make distclean" to get the
new version.

These are downloaded by the Makefile so they should really get removed
on "make clean".

nearest, or to maximum magnitude on ties) and with tests for detecting
underflow tininess after rounding.

"near_maxMag" (round to nearest, or to maximum magnitude on ties) and
"odd" (round to value with least-significant bit set), and with support
for choosing tininess detection on underflow (tininess detected either
before or after rounding).

source code.

modes "near_maxMag" (round to nearest, or to maximum magnitude on ties) and
"odd" (round to value with least-significant bit set).

of a result is now done by the shared rounding module, 'RoundRawFNToRecFN'.

conventions.

separate module and adding more rounding control options (not yet truly
supported).

more cases correctly.

the input floating-point value is zero.

Stop comparing Bits

Chisel 3 doesn't support comparison on Bits.

the output is an unsigned integer.

first macrostage of module `DivSqrtRecF64_mulAddZ31'.

This builds correctly for me

Chisel 3 compatibility.

They differ in their effects on width inference.

x >> 3 results in a node that's 3 bits narrower than x.
x >> UInt(3) results in a node with the same width as x.