The pipeline will have various parallel segments.  One of those
segments will include the basic FP operations.  Based on the C code I
committed and posted about earlier, I have compared the MUL and ADDSUB
pipelines and rearranged them so that what's the same between them is
combined.

Below is a sequence of pipeline stages.  "---" separates pipeline
stages.  If addsub and mul do the same thing, just that one thing is
listed.  If they do different things, then the format is "mul /
addsub".  There are two input operands, A, and B.



-----------
denormalize
add exponents   /  subtract exponents, subtract mantissas
compute sign of product  /  compute if this is an add or subtract
-----------
multiplier stage 1  /  swap operands so that A >= B
-----------
multiplier stage 2  /  shift B.mant right such that B.exp == A.exp
-----------
multiplier stage 3  /  addsub
-----------
multiplier stage 4  /  compute left shift for normalization (priority encoder)
-----------
[nothing]  /  shift mantissa left to normalize
-----------
round
-----------
shift right if round caused carry
-----------
overflow to infinity
underflow to zero
-----------


-- 
Timothy Normand Miller
http://www.cse.ohio-state.edu/~millerti
Open Graphics Project
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