Difference between revisions of "Instruction Set/fmafe"
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− | <div style="font-size:80%;line-height:90%;margin-bottom:2em">[[Speculation| | + | <div style="font-size:80%;line-height:90%;margin-bottom:2em">[[Speculation|speculable]] [[Encoding|exu stream]] [[Decode|exu block]] [[Phasing|compute phase]] operation [[Domains|in the binary floating point value domain]] [[Rounding|and rounds to nearest, ties toward even adjacent value]]<br /> |
'''native on:''' [[Cores/Silver|Silver]] [[Cores/Gold|Gold]] <br /> | '''native on:''' [[Cores/Silver|Silver]] [[Cores/Gold|Gold]] <br /> | ||
</div> | </div> |
Revision as of 09:32, 9 February 2015
speculable exu stream exu block compute phase operation in the binary floating point value domain and rounds to nearest, ties toward even adjacent value
Binary floating point fused multiply-add. As usual for those, it yields a higher precision than doing it separately, and is faster too. Rounds towards even.
operands: like Addf [ff:f]
Returns x*y+z on the belt.
encoding:
fmafe(f x)
,
exuArgs(op arg0, op arg1)
Core | In Slots | Latencies |
---|---|---|
Silver | E0 E1 | w,w:w=6 wv,wv:wv=6 d,d:d=7 dv,dv:dv=7 q,q:q=8 qv,qv:qv=8 |
Gold | E0 E1 E2 E3 | w,w:w=6 wv,wv:wv=6 d,d:d=7 dv,dv:dv=7 q,q:q=8 qv,qv:qv=8 |
fmafe(f x, f y, f z, f w) → f r0, f r1
operands: like Fmasf [ff:f]
This is a fused multiply-add-subtract. An excellent way to make full use of all Functional Units in the 2 Slots.
r0 is x*y+z*w
r1 is x*y-z*w
encoding:
fmafe(f x, f y)
,
exuArgs(op arg0, op arg1)
Core | In Slots | Latencies |
---|---|---|
Silver | E0 | w,w:w,w=6,6 wv,wv:wv,wv=6,6 d,d:d,d=7,7 dv,dv:dv,dv=7,7 q,q:q,q=8,8 qv,qv:qv,qv=8,8 |
Gold | E0 E2 | w,w:w,w=6,6 wv,wv:wv,wv=6,6 d,d:d,d=7,7 dv,dv:dv,dv=7,7 q,q:q,q=8,8 qv,qv:qv,qv=8,8 |
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