Difference between revisions of "Instruction Set/narrowus"
From Mill Computing Wiki
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| − | + | Half the width of an unsigned integer value. Saturating on overflow. | |
| + | |||
| + | 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. | ||
| + | |||
---- | ---- | ||
<code style="font-size:130%"><b style="color:#050">narrowus</b>(<span style="color:#009">[[Domains#u|u]]</span> <span title="belt operand from ops window">v</span>) → [[Domains#u|u]] r<sub>0</sub></code> | <code style="font-size:130%"><b style="color:#050">narrowus</b>(<span style="color:#009">[[Domains#u|u]]</span> <span title="belt operand from ops window">v</span>) → [[Domains#u|u]] r<sub>0</sub></code> | ||
Revision as of 00:05, 3 January 2015
realizing exu stream exu block compute phase operation in the unsigned integer value domain using saturating overflow behavior
native on: all
Half the width of an unsigned integer value. Saturating on overflow.
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.
operands: like Narrow [xx:½x]
| Core | In Slots | Latencies |
|---|---|---|
| Tin | E0 | 2 |
| Copper | E0 E1 | 2 |
| Silver | E0 E1 E2 E3 | 2 |
| Gold | E0 E1 E2 E3 E4 E5 E6 E7 | 2 |
| Decimal8 | E0 E1 E2 E3 | 2 |
| Decimal16 | E0 E1 E2 E3 | 2 |
operands: like Narrowv [XX:½x]
| Core | In Slots | Latencies |
|---|---|---|
| Tin | E0 | 2 |
| Copper | E0 E1 | 2 |
| Silver | E0 E1 E2 E3 | 2 |
| Gold | E0 E1 E2 E3 E4 E5 E6 E7 | 2 |
| Decimal8 | E0 E1 E2 E3 | 2 |
| Decimal16 | E0 E1 E2 E3 | 2 |
Instruction Set, alphabetical, Instruction Set by Category, Instruction Set, sortable, filterable
