Vec.rst

Vec

Description

A Vec is a composite type that defines a group of indexed signals (of any SpinalHDL basic type) under a single name.

Declaration

The syntax to declare a vector is as follows:

Declaration	Description
Vec.fill(size: Int)(type: Data)	Create a vector of size elements of type Data
Vec(x, y, ...)	Create a vector where indexes point to the provided elements. Does not create new hardware signals. This constructor supports mixed element width.

Examples

// Create a vector of 2 signed integers
val myVecOfSInt = Vec.fill(2)(SInt(8 bits))
myVecOfSInt(0) := 2                   // assignment to populate index 0
myVecOfSInt(1) := myVecOfSInt(0) + 3  // assignment to populate index 1

// Create a vector of 3 different type elements
val myVecOfMixedUInt = Vec(UInt(3 bits), UInt(5 bits), UInt(8 bits))

val x, y, z = UInt(8 bits)
val myVecOf_xyz_ref = Vec(x, y, z)

// Iterate on a vector
for(element <- myVecOf_xyz_ref) {
  element := 0   // Assign x, y, z with the value 0
}

// Map on vector
myVecOfMixedUInt.map(_ := 0) // Assign all elements with value 0

// Assign 3 to the first element of the vector
myVecOf_xyz_ref(1) := 3

Operators

The following operators are available for the Vec type:

Comparison

Operator	Description	Return type
x === y	Equality	Bool
x =/= y	Inequality	Bool

// Create a vector of 2 signed integers
val vec2 = Vec.fill(2)(SInt(8 bits))
val vec1 = Vec.fill(2)(SInt(8 bits))

myBool := vec2 === vec1  // Compare all elements
// is equivalent to:
//myBool := vec2(0) === vec1(0) && vec2(1) === vec1(1)

Type cast

Operator	Description	Return
x.asBits	Binary cast to Bits	Bits(w(x) bits)

// Create a vector of 2 signed integers
val vec1 = Vec.fill(2)(SInt(8 bits))

myBits_16bits := vec1.asBits

Misc

Operator	Description	Return
x.getBitsWidth	Return the full size of the Vec	Int

// Create a vector of 2 signed integers
val vec1 = Vec.fill(2)(SInt(8 bits))

println(widthOf(vec1)) // 16

Lib helper functions

Note

You need to import import spinal.lib._ to put these functions in scope.

Operator	Description	Return
x.sCount(condition: T => Bool)	Count the number of occurence matching a given condition in the Vec.	UInt
x.sCount(value: T)	Count the number of occurence of a value in the Vec.	UInt
x.sExists(condition: T => Bool)	Check if there is a matching condition in the Vec.	Bool
x.sContains(value: T)	Check if there is an element with a given value present in the Vec.	Bool
x.sFindFirst(condition: T => Bool)	Find the first element matching the given condition in the Vec, return if any index was successfully found and the index of that element.	(Bool, UInt)
x.reduceBalancedTree(op: (T, T) => T)	Balanced reduce function, to try to minimize the depth of the resulting circuit. op should be commutative and associative.	T
x.shuffle(indexMapping: Int => Int)	Shuffle the Vec using a function that maps the old indexes to new ones.	Vec[T]

import spinal.lib._

// Create a vector with 4 unsigned integers
val vec1 = Vec.fill(4)(UInt(8 bits))

// ... the vector is actually assigned somewhere

val c1: UInt = vec1.sCount(_ < 128) // how many values are lower than 128 in vec
val c2: UInt = vec1.sCount(0) // how many values are equal to zero in vec

val b1: Bool = vec1.sExists(_ > 250) // is there a element bigger than 250
val b2: Bool = vec1.sContains(0) // is there a zero in vec

val (u1Found, u1): (Bool, UInt) = vec1.sFindFirst(_ < 10) // get the index of the first element lower than 10
val u2: UInt = vec1.reduceBalancedTree(_ + _) // sum all elements together

Note

The sXXX prefix is used to disambiguate with respect to identically named Scala functions that accept a lambda function as argument.