class GaloisLFSR extends PRNG with LFSR
Galois Linear Feedback Shift Register (LFSR) generator.
A Galois LFSR can be generated by defining a width and a set of tap points. Optionally, an initial seed and a reduction operation (XOR, the default, or XNOR) can be used to augment the generated hardware. The resulting hardware has support for a run-time programmable seed (via PRNGIO.seed) and conditional increment (via PRNGIO.increment).
If the user specifies a seed, then a compile-time check is added that they are not initializing the LFSR to a state which will cause it to lock up. If the user does not set a seed, then the least significant bit of the state will be set or reset based on the choice of reduction operator.
In the example below, a 4-bit LFSR Galois LFSR is constructed. The tap points are defined as four and three (using LFSR convention of indexing from one). This results in the hardware configuration shown in the diagram.
val lfsr4 = Module(new GaloisLFSR(4, Set(4, 3)) // +-----------------+---------------------------------------------------------+ // | | | // | +-------+ v +-------+ +-------+ +-------+ | // | | | +---+ | | | | | | | // +-->| x^4 |-->|XOR|-->| x^3 |---------->| x^2 |---------->| x^1 |---+ // | | +---+ | | | | | | // +-------+ +-------+ +-------+ +-------+
If you require a maximal period Galois LFSR of a specific width, you can use MaxPeriodGaloisLFSR. If you only require a pseudorandom UInt you can use the GaloisLFSR companion object.
- Source
- GaloisLFSR.scala
- See also
https://en.wikipedia.org/wiki/Linear-feedback_shift_register#Galois_LFSRs
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- GaloisLFSR
- LFSR
- PRNG
- Module
- ImplicitReset
- ImplicitClock
- RawModule
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- AnyRef
- Any
- by BaseModuleExtensions
- by IsInstantiableExtensions
- by any2stringadd
- by StringFormat
- by Ensuring
- by ArrowAssoc
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- Public
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Instance Constructors
- new GaloisLFSR(width: Int, taps: Set[Int], seed: Option[BigInt] = Some(1), reduction: LFSRReduce = XOR, step: Int = 1, updateSeed: Boolean = false)
- width
the width of the LFSR
- taps
a set of tap points to use when constructing the LFSR
- seed
an initial value for internal LFSR state. If None, then the LFSR state LSB will be set to a known safe value on reset (to prevent lock up).
- reduction
- step
the number of state updates per cycle
- updateSeed
if true, when loading the seed the state will be updated as if the seed were the current state, if false, the state will be set to the seed
Value Members
- final def !=(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- final def ##: Int
- Definition Classes
- AnyRef → Any
- def +(other: String): String
- Implicit
- This member is added by an implicit conversion from GaloisLFSR toany2stringadd[GaloisLFSR] performed by method any2stringadd in scala.Predef.
- Definition Classes
- any2stringadd
- def ->[B](y: B): (GaloisLFSR, B)
- Implicit
- This member is added by an implicit conversion from GaloisLFSR toArrowAssoc[GaloisLFSR] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @inline()
- final def ==(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- def IO[T <: Data](iodef: => T)(implicit sourceInfo: SourceInfo): T
This must wrap the datatype used to set the io field of any Module.
This must wrap the datatype used to set the io field of any Module. i.e. All concrete modules must have defined io in this form: [lazy] val io[: io type] = IO(...[: io type])
Items in [] are optional.
The granted iodef must be a chisel type and not be bound to hardware.
Also registers an Data as a port, also performing bindings. Cannot be called once ports are requested (so that all calls to ports will return the same information). Internal API.
TODO(twigg): Specifically walk the Data definition to call out which nodes are problematic.
- Attributes
- protected
- Definition Classes
- BaseModule
- def _bindIoInPlace(iodef: Data)(implicit sourceInfo: SourceInfo): Unit
Chisel2 code didn't require the IO(...) wrapper and would assign a Chisel type directly to io, then do operations on it.
Chisel2 code didn't require the IO(...) wrapper and would assign a Chisel type directly to io, then do operations on it. This binds a Chisel type in-place (mutably) as an IO.
- Attributes
- protected
- Definition Classes
- BaseModule
- var _closed: Boolean
- Attributes
- protected
- Definition Classes
- BaseModule
- def _moduleDefinitionIdentifierProposal: String
- Attributes
- protected
- Definition Classes
- BaseModule
- def _sourceInfo: SourceInfo
- Attributes
- protected
- Definition Classes
- BaseModule
- def _traitModuleDefinitionIdentifierProposal: Option[String]
- Attributes
- protected
- Definition Classes
- BaseModule
- final def asInstanceOf[T0]: T0
- Definition Classes
- Any
- def atModuleBodyEnd(gen: => Unit): Unit
Hook to invoke hardware generators after the rest of the Module is constructed.
Hook to invoke hardware generators after the rest of the Module is constructed.
This is a power-user API, and should not normally be needed.
In rare cases, it is necessary to run hardware generators at a late stage, but still within the scope of the Module. In these situations, atModuleBodyEnd may be used to register such generators. For example:
class Example extends RawModule { atModuleBodyEnd { val extraPort0 = IO(Output(Bool())) extraPort0 := 0.B } }
Any generators registered with atModuleBodyEnd are the last code to execute when the Module is constructed. The execution order is:
- The constructors of any super classes or traits the Module extends
- The constructor of the Module itself
- The atModuleBodyEnd generators
The atModuleBodyEnd generators execute in the lexical order they appear in the Module constructor.
For example:
trait Parent { // Executes first. val foo = ... } class Example extends Parent { // Executes second. val bar = ... atModuleBodyEnd { // Executes fourth. val qux = ... } atModuleBodyEnd { // Executes fifth. val quux = ... } // Executes third.. val baz = ... }
If atModuleBodyEnd is used in a Definition, any generated hardware will be included in the Definition. However, it is currently not possible to annotate any val within atModuleBodyEnd as @public.
- Attributes
- protected
- Definition Classes
- RawModule
- def circuitName: String
- Definition Classes
- HasId
- final val clock: Clock
- Definition Classes
- Module
- def clone(): AnyRef
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.CloneNotSupportedException]) @native()
- final val definitionIdentifier: String
Represents an eagerly-determined unique and descriptive identifier for this module
Represents an eagerly-determined unique and descriptive identifier for this module
- Definition Classes
- BaseModule
- def delta(s: Seq[Bool]): Seq[Bool]
State update function
- def desiredName: String
The desired name of this module (which will be used in generated FIRRTL IR or Verilog).
The desired name of this module (which will be used in generated FIRRTL IR or Verilog).
The name of a module approximates the behavior of the Java Reflection
getSimpleName
method https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html#getSimpleName-- with some modifications:- Anonymous modules will get an
"_Anon"
tag - Modules defined in functions will use their class name and not a numeric name- Definition Classes
- BaseModule
- Note
If you want a custom or parametric name, override this method.
- def endIOCreation()(implicit si: SourceInfo): Unit
Disallow any more IO creation for this module.
Disallow any more IO creation for this module.
- Definition Classes
- BaseModule
- def ensuring(cond: (GaloisLFSR) => Boolean, msg: => Any): GaloisLFSR
- Implicit
- This member is added by an implicit conversion from GaloisLFSR toEnsuring[GaloisLFSR] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- def ensuring(cond: (GaloisLFSR) => Boolean): GaloisLFSR
- Implicit
- This member is added by an implicit conversion from GaloisLFSR toEnsuring[GaloisLFSR] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- def ensuring(cond: Boolean, msg: => Any): GaloisLFSR
- Implicit
- This member is added by an implicit conversion from GaloisLFSR toEnsuring[GaloisLFSR] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- def ensuring(cond: Boolean): GaloisLFSR
- Implicit
- This member is added by an implicit conversion from GaloisLFSR toEnsuring[GaloisLFSR] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- final def eq(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- def equals(that: Any): Boolean
- Definition Classes
- HasId → AnyRef → Any
- def finalize(): Unit
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.Throwable])
- final def getClass(): Class[_ <: AnyRef]
- Definition Classes
- AnyRef → Any
- Annotations
- @native()
- def getCommands: Seq[Command]
- Attributes
- protected
- Definition Classes
- RawModule
- def getModulePorts: Seq[Data]
- Attributes
- protected[chisel3]
- Definition Classes
- BaseModule
- def hasSeed: Boolean
- returns
Whether either autoName or suggestName has been called
- Definition Classes
- HasId
- def hashCode(): Int
- Definition Classes
- HasId → AnyRef → Any
- def implicitClock: Clock
Method that should point to the user-defined Clock
Method that should point to the user-defined Clock
- Attributes
- protected
- Definition Classes
- Module → ImplicitClock
- def implicitReset: Reset
Method that should point to the user-defined Reset
Method that should point to the user-defined Reset
- Attributes
- protected
- Definition Classes
- Module → ImplicitReset
- def instanceName: String
Signal name (for simulation).
Signal name (for simulation).
- Definition Classes
- BaseModule → HasId → InstanceId
- val io: PRNGIO
- Definition Classes
- PRNG
- final def isInstanceOf[T0]: Boolean
- Definition Classes
- Any
- final lazy val name: String
Legalized name of this module.
Legalized name of this module.
- Definition Classes
- BaseModule
- final def ne(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- final def nextState(s: Seq[Bool]): Seq[Bool]
The method that will be used to update the state of this PRNG
The method that will be used to update the state of this PRNG
- s
input state
- returns
the next state after
step
applications of PRNG.delta
- Definition Classes
- PRNG
- final def notify(): Unit
- Definition Classes
- AnyRef
- Annotations
- @native()
- final def notifyAll(): Unit
- Definition Classes
- AnyRef
- Annotations
- @native()
- def parentModName: String
- Definition Classes
- HasId → InstanceId
- def parentPathName: String
- Definition Classes
- HasId → InstanceId
- def pathName: String
- Definition Classes
- HasId → InstanceId
- def portsContains(elem: Data): Boolean
- Attributes
- protected
- Definition Classes
- BaseModule
- def portsSize: Int
- Attributes
- protected
- Definition Classes
- BaseModule
- val reduction: LFSRReduce
The binary reduction operation used by this LFSR, either XOR or XNOR.
The binary reduction operation used by this LFSR, either XOR or XNOR. This has the effect of mandating what seed is invalid.
- Definition Classes
- GaloisLFSR → LFSR
- final val reset: Reset
- Definition Classes
- Module
- def resetType: Type
Override this to explicitly set the type of reset you want on this module , before any reset inference
Override this to explicitly set the type of reset you want on this module , before any reset inference
- Definition Classes
- Module
- def resetValue: Vec[Bool]
Allow implementations to override the reset value, e.g., if some bits should be don't-cares.
- val seed: Option[BigInt]
- Definition Classes
- PRNG
- def suggestName(seed: => String): GaloisLFSR.this.type
Takes the first seed suggested.
Takes the first seed suggested. Multiple calls to this function will be ignored. If the final computed name conflicts with another name, it may get uniquified by appending a digit at the end.
Is a higher priority than
autoSeed
, in that regardless of whetherautoSeed
was called, suggestName will always take precedence.- seed
The seed for the name of this component
- returns
this object
- Definition Classes
- HasId
- final def synchronized[T0](arg0: => T0): T0
- Definition Classes
- AnyRef
- final def toAbsoluteTarget: IsModule
Returns a FIRRTL ModuleTarget that references this object
Returns a FIRRTL ModuleTarget that references this object
- Definition Classes
- BaseModule → InstanceId
- Note
Should not be called until circuit elaboration is complete
- def toDefinition: Definition[GaloisLFSR]
- Implicit
- This member is added by an implicit conversion from GaloisLFSR toBaseModuleExtensions[GaloisLFSR] performed by method BaseModuleExtensions in chisel3.experimental.BaseModule.
- Definition Classes
- BaseModuleExtensions
- final def toNamed: ModuleName
Returns a FIRRTL ModuleName that references this object
Returns a FIRRTL ModuleName that references this object
- Definition Classes
- BaseModule → InstanceId
- Note
Should not be called until circuit elaboration is complete
- final def toRelativeTarget(root: Option[BaseModule]): IsModule
Returns a FIRRTL ModuleTarget that references this object, relative to an optional root.
Returns a FIRRTL ModuleTarget that references this object, relative to an optional root.
If
root
is defined, the target is a hierarchical path starting fromroot
.If
root
is not defined, the target is a hierarchical path equivalent totoAbsoluteTarget
.- Definition Classes
- BaseModule
- Note
If
,root
is defined, and has not finished elaboration, this must be called withinatModuleBodyEnd
.The BaseModule must be a descendant of
,root
, if it is defined.This doesn't have special handling for Views.
- def toString(): String
- Definition Classes
- AnyRef → Any
- final def toTarget: ModuleTarget
Returns a FIRRTL ModuleTarget that references this object
Returns a FIRRTL ModuleTarget that references this object
- Definition Classes
- BaseModule → InstanceId
- Note
Should not be called until circuit elaboration is complete
- final def wait(): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException]) @native()
- val width: Int
- Definition Classes
- PRNG
Shadowed Implicit Value Members
- def toInstance: Instance[GaloisLFSR]
- Implicit
- This member is added by an implicit conversion from GaloisLFSR toBaseModuleExtensions[GaloisLFSR] performed by method BaseModuleExtensions in chisel3.experimental.BaseModule.
- Shadowing
- This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
To access this member you can use a type ascription:(galoisLFSR: BaseModuleExtensions[GaloisLFSR]).toInstance
- Definition Classes
- BaseModuleExtensions
- def toInstance: Instance[GaloisLFSR]
- Implicit
- This member is added by an implicit conversion from GaloisLFSR toIsInstantiableExtensions[GaloisLFSR] performed by method IsInstantiableExtensions in chisel3.experimental.hierarchy.core.IsInstantiable.
- Shadowing
- This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
To access this member you can use a type ascription:(galoisLFSR: IsInstantiableExtensions[GaloisLFSR]).toInstance
- Definition Classes
- IsInstantiableExtensions
Deprecated Value Members
- def formatted(fmtstr: String): String
- Implicit
- This member is added by an implicit conversion from GaloisLFSR toStringFormat[GaloisLFSR] performed by method StringFormat in scala.Predef.
- Definition Classes
- StringFormat
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.12.16) Use
formatString.format(value)
instead ofvalue.formatted(formatString)
, or use thef""
string interpolator. In Java 15 and later,formatted
resolves to the new method in String which has reversed parameters.
- def override_clock: Option[Clock]
- Attributes
- protected
- Definition Classes
- Module
- Annotations
- @deprecated
- Deprecated
(Since version Chisel 3.5) Use withClock at Module instantiation
- def override_clock_=(rhs: Option[Clock]): Unit
- Attributes
- protected
- Definition Classes
- Module
- Annotations
- @deprecated
- Deprecated
(Since version Chisel 3.5) Use withClock at Module instantiation
- def override_reset: Option[Bool]
- Attributes
- protected
- Definition Classes
- Module
- Annotations
- @deprecated
- Deprecated
(Since version Chisel 3.5) Use withClock at Module instantiation
- def override_reset_=(rhs: Option[Bool]): Unit
- Attributes
- protected
- Definition Classes
- Module
- Annotations
- @deprecated
- Deprecated
(Since version Chisel 3.5) Use withClock at Module instantiation
- def →[B](y: B): (GaloisLFSR, B)
- Implicit
- This member is added by an implicit conversion from GaloisLFSR toArrowAssoc[GaloisLFSR] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use
->
instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.