View source for Instruction Set/narrowffz

{{DISPLAYTITLE:narrowffz}}
<div style="font-size:80%;line-height:90%;margin-bottom:2em">[[Speculation|realizing]]&nbsp;&nbsp;[[Encoding|exu stream]]&nbsp;&nbsp;[[Decode|exu block]]&nbsp;&nbsp;[[Phasing|compute phase]]&nbsp;&nbsp; operation&nbsp;&nbsp; [[Domains|in the binary floating point value domain]]&nbsp;&nbsp; [[Rounding|and rounds to nearest, ties away from zero]]<br />
'''native on:''' [[Cores/Silver|Silver]] <br />
</div>

Half the width of a binary float value. Rounding to nearest away from zero.

Can produce the [http://en.wikipedia.org/wiki/IEEE_floating_point IEEE 754] 16bit binary float interchange format.
  
This is not a [[Speculable]] operation. The reason for this is the impossibility to fit all of the [[NaR]] payload into values smaller than 32bit.
Nominally this would only require the narrowing of 32bit values to be not speculable, but for simplicity reasons in hardware and compiler this is not so.
If narrowing should prove a big bottleneck this can be revisited.

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<code style="font-size:130%"><b style="color:#050">narrowffz</b>(<span style="color:#009">[[Domains#f|f]]</span> <span title="belt operand from ops window">v1</span>, <span style="color:#009">[[Domains#f|f]]</span> <span title="belt operand from ops window">v2</span>) &#8594; [[Domains#f|f]] r<sub>0</sub></code>
<div style="font-size:80%;line-height:90%;margin-bottom:2em">'''operands:''' [[Operands#likeNarrowvf|like Narrowvf [FF:&#189;F]]]
</div>
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{| class="mw-collapsible mw-collapsed wikitable" data-expandtext="&#9656;" data-collapsetext="&#9662;"
! [[Cores|Core]] || [[Slot|In Slots]]|| [[Latency|Latencies]]
|-
| [[Cores/Silver/Encoding#narrowffz|Silver]] || E0 E1 || 
|}

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<code style="font-size:130%"><b style="color:#050">narrowffz</b>(<span style="color:#009">[[Domains#f|f]]</span> <span title="belt operand from ops window">op0</span>, <i><span style="color:#009">[[Immediates#width|width]]</span> <span title="data width and vector length (exu)">width0</span></i>) &#8594; [[Domains#f|f]] r<sub>0</sub></code>
<div style="font-size:80%;line-height:90%;margin-bottom:2em">'''operands:''' [[Operands#likeNarrowf|like Narrowf [ff:&#189;f]]]
</div>
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{| class="mw-collapsible mw-collapsed wikitable" data-expandtext="&#9656;" data-collapsetext="&#9662;"
! [[Cores|Core]] || [[Slot|In Slots]]|| [[Latency|Latencies]]
|-
| [[Cores/Silver/Encoding#narrowffz|Silver]] || E0 E1 || 
|}


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