Difference between revisions of "Instruction Set/fmafn"
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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 toward negative infinity]]<br /> |
'''native on:''' [[Cores/Silver|Silver]] [[Cores/Gold|Gold]] <br /> | '''native on:''' [[Cores/Silver|Silver]] [[Cores/Gold|Gold]] <br /> | ||
</div> | </div> | ||
Revision as of 09:25, 9 February 2015
speculable exu stream exu block compute phase operation in the binary floating point value domain and rounds toward negative infinity
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 negative infinity.
operands: like Addf [ff:f]
Returns x*y+z on the belt.
encoding:
fmafn(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 |
fmafn(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:
fmafn(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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