Add pipelining API documentation #226
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Co-authored-by: Andreas Wallner <[email protected]>
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| val PC = Payload(UInt(32 bits)) | ||
| n0(PC) := 0x42 | ||
| n0(PC, "true") := 0x42 |
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So is the above two lines represent different signals?
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| * - API | ||
| - Description | ||
| * - node.setAlwaysValid() |
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We have setIdle and setBlocked in Stream, if we need to provide a setAlwaysXXXX style function to keep consistency to lower study curve.
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It isn't realy the same use case.
setAlwaysValid isn't just valid := True, but also mean that the valid signal is always high in a static way, will never be False ever.
while setIdle is used to provide a value which can be overriden.
Still any sugestion for better API name is welcome :D
| val c01 = StageLink(n0, n1) | ||
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| S2mLink |
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So there are three types of link to represent the different Link strategy. How about add an apply function for the Link class and create different XXXLink by parameters. So that the code can be unchanged while Link type changing.
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Sure, this can be added as an tool on the top of the existing API. I didn't focussed much on that part of things yet
| * - throwWhen(Bool) | ||
| - Allows to cancel the current transaction from the pipeline (clear down.valid and c the transaction driver) | ||
| * - forgetOneWhen(Bool) | ||
| - Allows to request the upstream to forget the current transaction (but doesn't clear the down.valid) |
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What does the forget mean here, it will cancel the upstream's current transaction?
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yes, i'm replacing "the current" by "its current"
| - Allows to cancel the current transaction from the pipeline (clear down.valid and c the transaction driver) | ||
| * - forgetOneWhen(Bool) | ||
| - Allows to request the upstream to forget the current transaction (but doesn't clear the down.valid) | ||
| * - ignoreReadyWhen(Bool) |
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This name is hard to understand for me. What the purpose for this? I guess it is to hang on the downstream transaction and fire upstream's?
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forgetOneWhen ?
It will not hang anything, just make the upstream transaction driver "forget" about its current state.
That's a light weight to flush / remove something from the pipeline without having to manipulate the ready wire
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forgetOneWhen ? It will not hang anything, just make the upstream transaction driver "forget" about its current state. That's a light weight to flush / remove something from the pipeline without having to manipulate the ready wire
i mean the ignoreReadyWhen
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Ahhh. it is to fire the upstream.
It doesn't hang downstream
Its usage is to implement some logic to flush / remove elements of a pipeline.
You can do that for instance by combining ignoreReadyWhen and terminateWhen
| * - ignoreReadyWhen(Bool) | ||
| - Allows to ignore the downstream ready (set up.ready) | ||
| * - duplicateWhen(Bool) | ||
| - Allows to duplicate the current transaction (clear up.ready) |
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Does this mean split one transaction into two?
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Yes, it alows the transaction to eventualy duplicate downstream while holding a copy in the current node.
WIP
Document SpinalHDL/SpinalHDL#1237