summaryrefslogtreecommitdiff
path: root/docs/src/wiki-deprecated/experimental-features.md
diff options
context:
space:
mode:
authorJack Koenig2021-02-04 10:07:56 -0800
committerGitHub2021-02-04 10:07:56 -0800
commit8fa46071c382b6fdecba86a9bab729526fa4fbe2 (patch)
tree41123124a8f27ec482693527c5140a8771b8881c /docs/src/wiki-deprecated/experimental-features.md
parentf45216effc573d33d4aa4e525cff955ab332efbd (diff)
Minor docs improvements (#1774)
* Fix some botched formatting (replace ```mdoc scala with ```scala mdoc) * Replace some unnecessary uses of triple backticks with single backticks * Move appendix docs from wiki-deprecated/ to appendix/ * This will require an update on the website as well * Update Bundle literal docs
Diffstat (limited to 'docs/src/wiki-deprecated/experimental-features.md')
-rw-r--r--docs/src/wiki-deprecated/experimental-features.md119
1 files changed, 0 insertions, 119 deletions
diff --git a/docs/src/wiki-deprecated/experimental-features.md b/docs/src/wiki-deprecated/experimental-features.md
deleted file mode 100644
index d36b2946..00000000
--- a/docs/src/wiki-deprecated/experimental-features.md
+++ /dev/null
@@ -1,119 +0,0 @@
----
-layout: docs
-title: "Experimental Features"
-section: "chisel3"
----
-
-Chisel has a number of new features that are worth checking out. This page is an informal list of these features and projects.
-
-### FixedPoint
-FixedPoint numbers are basic *Data* type along side of UInt, SInt, etc. Most common math and logic operations
-are supported. Chisel allows both the width and binary point to be inferred by the Firrtl compiler which can simplify
-circuit descriptions. See [FixedPointSpec](https://github.com/freechipsproject/chisel3/tree/master/src/test/scala/chiselTests/FixedPointSpec.scala)
-
-### Module Variants
-The standard Chisel *Module* requires a ```val io = IO(...)```, the experimental package introduces several
-new ways of defining Modules
-- BaseModule: no contents, instantiable
-- BlackBox extends BaseModule
-- UserDefinedModule extends BaseModule: this module can contain Chisel RTL. No default clock or reset lines. No default IO. - User should be able to specify non-io ports, ideally multiple of them.
-- ImplicitModule extends UserModule: has clock, reset, and io, essentially current Chisel Module.
-- RawModule: will be the user-facing version of UserDefinedModule
-- Module: type-aliases to ImplicitModule, the user-facing version of ImplicitModule.
-
-### Bundle Literals
-
-Chisel 3.2 introduces an experimental mechanism for Bundle literals in #820, but this feature is largely incomplete and not ready for user code yet. The following is provided as documentation for library writers who want to take a stab at using this mechanism for their library's bundles.
-
-```mdoc scala
-class MyBundle extends Bundle {
- val a = UInt(8.W)
- val b = Bool()
-
- // Bundle literal constructor code, which will be auto-generated using macro annotations in
- // the future.
- import chisel3.core.BundleLitBinding
- import chisel3.internal.firrtl.{ULit, Width}
-
- // Full bundle literal constructor
- def Lit(aVal: UInt, bVal: Bool): MyBundle = {
- val clone = cloneType
- clone.selfBind(BundleLitBinding(Map(
- clone.a -> litArgOfBits(aVal),
- clone.b -> litArgOfBits(bVal)
- )))
- clone
- }
-
- // Partial bundle literal constructor
- def Lit(aVal: UInt): MyBundle = {
- val clone = cloneType
- clone.selfBind(BundleLitBinding(Map(
- clone.a -> litArgOfBits(aVal)
- )))
- clone
- }
-}
-```
-
-Example usage:
-
-```scala
-val outsideBundleLit = (new MyBundle).Lit(42.U, true.B)
-```
-
-### Interval Type
-
-**Intervals** are a new experimental numeric type that comprises UInt, SInt and FixedPoint numbers.
-It augments these types with range information, i.e. upper and lower numeric bounds.
-This information can be used to exercise tighter programmatic control over the ultimate widths of
-signals in the final circuit. The **Firrtl** compiler can infer this range information based on
-operations and earlier values in the circuit. Intervals support all the ordinary bit and arithmetic operations
-associated with UInt, SInt, and FixedPoint and adds the following methods for manipulating the range of
-a **source** Interval with the IntervalRange of **target** Interval
-
-#### Clip -- Fit the value **source** into the IntervalRange of **target**, saturate if out of bounds
-The clip method applied to an interval creates a new interval based on the argument to clip,
-and constructs the necessary hardware so that the source Interval's value will be mapped into the new Interval.
-Values that are outside the result range will be pegged to either maximum or minimum of result range as appropriate.
-
-> Generates necessary hardware to clip values, values greater than range are set to range.high, values lower than range are set to range min.
-
-#### Wrap -- Fit the value **source** into the IntervalRange of **target**, wrapping around if out of bounds
-The wrap method applied to an interval creates a new interval based on the argument to wrap,
-and constructs the necessary
-hardware so that the source Interval's value will be mapped into the new Interval.
-Values that are outside the result range will be wrapped until they fall within the result range.
-
-> Generates necessary hardware to wrap values, values greater than range are set to range.high, values lower than range are set to range min.
-
-> Does not handle out of range values that are less than half the minimum or greater than twice maximum
-
-#### Squeeze -- Fit the value **source** into the smallest IntervalRange based on source and target.
-The squeeze method applied to an interval creates a new interval based on the argument to clip, the two ranges must overlap
-behavior of squeeze with inputs outside of the produced range is undefined.
-
-> Generates no hardware, strictly a sizing operation
-
-##### Range combinations
-
-| Condition | A.clip(B) | A.wrap(B) | A.squeeze(B) |
-| --------- | --------------- | --------------- | --------------- |
-| A === B | max(Alo, Blo), min(Ahi, Bhi) | max(Alo, Blo), min(Ahi, Bhi) | max(Alo, Blo), min(Ahi, Bhi) |
-| A contains B | max(Alo, Blo), min(Ahi, Bhi) | max(Alo, Blo), min(Ahi, Bhi) | max(Alo, Blo), min(Ahi, Bhi) |
-| B contains A | max(Alo, Blo), min(Ahi, Bhi) | max(Alo, Blo), min(Ahi, Bhi) | max(Alo, Blo), min(Ahi, Bhi) |
-| A min < B min, A max in B | max(Alo, Blo), min(Ahi, Bhi) | max(Alo, Blo), min(Ahi, Bhi) | max(Alo, Blo), min(Ahi, Bhi) |
-| A min in B, A max > B max | max(Alo, Blo), min(Ahi, Bhi) | max(Alo, Blo), min(Ahi, Bhi) | max(Alo, Blo), min(Ahi, Bhi) |
-| A strictly less than B | error | error | error |
-| A strictly greater than B | error | error | error |
-
-
-#### Applying binary point operators to an Interval
-
-Consider a Interval with a binary point of 3: aaa.bbb
-
-| operation | after operation | binary point | lower | upper | meaning |
-| --------- | --------------- | ------------ | ----- | ----- | ------- |
-| setBinaryPoint(2) | aaa.bb | 2 | X | X | set the precision |
-| shiftLeftBinaryPoint(2) | a.aabbb | 5 | X | X | increase the precision |
-| shiftRighBinaryPoint(2) | aaaa.b | 1 | X | X | reduce the precision |