diff options
Diffstat (limited to 'src/main/scala/firrtl/passes/Passes.scala')
| -rw-r--r-- | src/main/scala/firrtl/passes/Passes.scala | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/src/main/scala/firrtl/passes/Passes.scala b/src/main/scala/firrtl/passes/Passes.scala index 0405701f..66437556 100644 --- a/src/main/scala/firrtl/passes/Passes.scala +++ b/src/main/scala/firrtl/passes/Passes.scala @@ -228,6 +228,16 @@ object Legalize extends Pass { e } } + private def legalizeBits(expr: DoPrim): Expression = { + lazy val (hi, low) = (expr.consts(0), expr.consts(1)) + lazy val mask = (BigInt(1) << (hi - low + 1).toInt) - 1 + lazy val width = IntWidth(hi - low + 1) + expr.args.head match { + case UIntLiteral(value, _) => UIntLiteral((value >> low.toInt) & mask, width) + case SIntLiteral(value, _) => SIntLiteral((value >> low.toInt) & mask, width) + case _ => expr + } + } private def legalizeConnect(c: Connect): Statement = { val t = c.loc.tpe val w = bitWidth(t) @@ -246,6 +256,7 @@ object Legalize extends Pass { def legalizeE(expr: Expression): Expression = expr map legalizeE match { case prim: DoPrim => prim.op match { case Shr => legalizeShiftRight(prim) + case Bits => legalizeBits(prim) case _ => prim } case e => e // respect pre-order traversal |