Difference between revisions of "Instruction Set/fmad"
From Mill Computing Wiki
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{{DISPLAYTITLE:fmad}} | {{DISPLAYTITLE:fmad}} | ||
| − | <div style="font-size:80%;line-height:90%;margin-bottom:2em">[[Speculation|realizing]] [[Encoding|exu stream]] [[Decode|exu block]] [[Phasing|compute phase]] operation [[Domains|in the decimal floating point value domain]] <br /> | + | <div style="font-size:80%;line-height:90%;margin-bottom:2em">[[Speculation|realizing]] [[Encoding|exu stream]] [[Decode|exu block]] [[Phasing|compute phase]] operation [[Domains|in the decimal floating point value domain]] [[Rounding|and rounds use current dynamic rounding mode]]<br /> |
'''native on:''' [[Cores/Decimal8|Decimal8]] [[Cores/Decimal16|Decimal16]] <br /> | '''native on:''' [[Cores/Decimal8|Decimal8]] [[Cores/Decimal16|Decimal16]] <br /> | ||
</div> | </div> | ||
| − | fused multiply-add | + | Decimal floating point fused multiply-add. |
| + | As usual for those, it yields a higher precision than doing it separately, and is faster too. | ||
| + | Uses current rounding behaviour. | ||
| + | |||
---- | ---- | ||
<code style="font-size:130%"><b style="color:#050">fmad</b>(<span style="color:#009">[[Domains#d|d]]</span> <span title="belt operand from ops window">x</span>, <span style="color:#009">[[Domains#d|d]]</span> <span title="belt operand from ops window">y</span>, <span style="color:#009">[[Domains#d|d]]</span> <span title="belt operand from ops | <code style="font-size:130%"><b style="color:#050">fmad</b>(<span style="color:#009">[[Domains#d|d]]</span> <span title="belt operand from ops window">x</span>, <span style="color:#009">[[Domains#d|d]]</span> <span title="belt operand from ops window">y</span>, <span style="color:#009">[[Domains#d|d]]</span> <span title="belt operand from ops | ||
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<div style="font-size:80%;line-height:90%;margin-bottom:2em">'''operands:''' [[Operands#likeAddd|like Addd [dd:d]]] | <div style="font-size:80%;line-height:90%;margin-bottom:2em">'''operands:''' [[Operands#likeAddd|like Addd [dd:d]]] | ||
</div> | </div> | ||
| − | <br /> | + | Returns x*y+z on the belt.<br /> |
'''encoding:''' | '''encoding:''' | ||
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<div style="font-size:80%;line-height:90%;margin-bottom:2em">'''operands:''' [[Operands#likeFmasd|like Fmasd [dd:d]]] | <div style="font-size:80%;line-height:90%;margin-bottom:2em">'''operands:''' [[Operands#likeFmasd|like Fmasd [dd:d]]] | ||
</div> | </div> | ||
| − | <br /> | + | This is a fused multiply-add-subtract. An excellent way to make full use of all [[Functional Unit]]s in the 2 [[Slot]]s.<br /> |
| + | r<sub>0</sub> is x*y+z*w<br /> | ||
| + | r<sub>1</sub> is x*y-z*w<br /><br /> | ||
'''encoding:''' | '''encoding:''' | ||
Revision as of 18:53, 20 December 2014
realizing exu stream exu block compute phase operation in the decimal floating point value domain and rounds use current dynamic rounding mode
Decimal floating point fused multiply-add. As usual for those, it yields a higher precision than doing it separately, and is faster too. Uses current rounding behaviour.
operands: like Addd [dd:d]
Returns x*y+z on the belt.
encoding:
fmad(d x)
,
exuArgs(op arg0, op arg1)
| Core | In Slots | Latencies |
|---|---|---|
| Decimal8 | E0 E1 | d,d:d=7 dv,dv:dv=7 q,q:q=8 qv,qv:qv=8 |
| Decimal16 | E0 E1 | d,d:d=7 dv,dv:dv=7 q,q:q=8 qv,qv:qv=8 |
fmad(d x, d y, d z, d w) → d r0, d r1
operands: like Fmasd [dd:d]
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:
fmad(d x, d y)
,
exuArgs(op arg0, op arg1)
| Core | In Slots | Latencies |
|---|---|---|
| Decimal8 | E0 | d,d:d,d=7,7 dv,dv:dv,dv=7,7 q,q:q,q=8,8 qv,qv:qv,qv=8,8 |
| Decimal16 | E0 | d,d:d,d=7,7 dv,dv:dv,dv=7,7 q,q:q,q=8,8 qv,qv:qv,qv=8,8 |
Instruction Set, alphabetical, Instruction Set by Category, Instruction Set, sortable, filterable
