Interval literal creation is inconsistent

[chick]

Type of issue: bug report | documentation

Impact: Possible API modification

Other information Not the discrepancy with the following Interval literals. Decimal values are encode using the .I arguments while BigInt and Int values are interpreted according to the .I arguments. I think this is likely to create confusion though the cat may already be out of the bag on this one.

import chisel3._

Statement	Value
val b = BigInt(-2)	b: scala.math.BigInt = -2
val e = BigDecimal(-2.0)	e: scala.math.BigDecimal = -2.0
val d = -2.0	d: Double = -2.0
val l = -2	l: Int = -2
val ib = b.I(2.BP)	ib: chisel3.experimental.Interval = Interval<2>(-2)
val ie = e.I(2.BP)	ie: chisel3.experimental.Interval = Interval<4>(-8)
val id = d.I(2.BP)	id: chisel3.experimental.Interval = Interval<4>(-8)
val il = l.I(2.BP)	il: chisel3.experimental.Interval = Interval<2>(-2)
ib.litToDouble	res0: Double = -0.5
ie.litToDouble	res1: Double = -2.0
id.litToDouble	res2: Double = -2.0
il.litToDouble	res3: Double = -0.5
ib.litValue()	res4: BigInt = -2
ie.litValue()	res5: BigInt = -8
id.litValue()	res6: BigInt = -8
il.litValue()	res7: BigInt = -2

What is the current behavior? When creating Interval literals the behavior is different for BigInts, Longs, and Ints, than it is for Double and BigDecimal. In the former case the bits of the number are interpreted according to the paramters of the cap-I conversion while the latter the number is the supplied

What is the expected behavior? Seems to me that the behavior should be the same as Double and BigDecimal

Please tell us about your environment: Chisel3 3.3

[chick]

Check behavior of FixedPoint with respect to above.

[chick]

Consider looking at scalafix to provide way conversion of existing code

[chick]

Addressed by PR #1509