firrtl_interpreter/Concrete.scala: randomSInt produces out of bounds value.

[Steve Burns]

I get this stack trace when running a medium sized design.

...
Exception during evaluation: error: ConcreteSInt(4140379555, 32) bad width 32 needs 33 @[Decoupled.scala 127:17]
Expression Evaluation stack
0 fifo_diag_1_1.Queue_1_1.ram_sim_value.T_71.data:MemIO -> fifo_diag_1_1.Queue_1_1.GEN_3
1 fifo_diag_1_1.Queue_1_1.GEN_3:Node -> validif(fifo_diag_1_1.Queue_1_1.do_enq, fifo_diag_1_1.Queue_1_1.io_enq_bits_sim_value)
error firrtl_interpreter.InterpreterException: error: ConcreteSInt(4140379555, 32) bad width 32 needs 33
firrtl_interpreter.InterpreterException: error: ConcreteSInt(4140379555, 32) bad width 32 needs 33
at firrtl_interpreter.ConcreteSInt.(Concrete.scala:329)
at firrtl_interpreter.Concrete$.randomSInt(Concrete.scala:285)
at firrtl_interpreter.LoFirrtlExpressionEvaluator.evaluate(LoFirrtlExpressionEvaluator.scala:308)
at firrtl_interpreter.LoFirrtlExpressionEvaluator$$anonfun$3.apply(LoFirrtlExpressionEvaluator.scala:413)
at firrtl_interpreter.LoFirrtlExpressionEvaluator$$anonfun$3.apply(LoFirrtlExpressionEvaluator.scala:408)
at firrtl_interpreter.Timer.apply(Timer.scala:40)
...

This should fix the issue, but I wasn't able to run a local build to check.

smburns@smburns-VirtualBox:~/SW/firrtl-interpreter$ git diff src
diff --git a/src/main/scala/firrtl_interpreter/Concrete.scala b/src/main/scala/firrtl_interpreter/Concrete
index 737dadc..5bab6eb 100644
--- a/src/main/scala/firrtl_interpreter/Concrete.scala
+++ b/src/main/scala/firrtl_interpreter/Concrete.scala
@@ -282,7 +282,7 @@ object Concrete {
}
}
def randomUInt(width: Int): ConcreteUInt = ConcreteUInt(randomBigInt(width), width)

• def randomSInt(width: Int): ConcreteSInt = ConcreteSInt(randomBigInt(width), width)
• def randomSInt(width: Int): ConcreteSInt = ConcreteSInt(randomBigInt(width)-(BigInt(1)<<(width-1)), wi
  def randomClock(): ConcreteClock = ConcreteClock(randomBigInt(1))
  }

[Steve Burns]

Added the correct code fence:

diff --git a/src/main/scala/firrtl_interpreter/Concrete.scala b/src/main/scala/firrtl_interpreter/Concrete.scala
index 737dadc..5bab6eb 100644
--- a/src/main/scala/firrtl_interpreter/Concrete.scala
+++ b/src/main/scala/firrtl_interpreter/Concrete.scala
@@ -282,7 +282,7 @@ object Concrete {
     }
   }
   def randomUInt(width: Int): ConcreteUInt  = ConcreteUInt(randomBigInt(width), width)
-  def randomSInt(width: Int): ConcreteSInt  = ConcreteSInt(randomBigInt(width), width)
+  def randomSInt(width: Int): ConcreteSInt  = ConcreteSInt(randomBigInt(width)-(BigInt(1)<<(width-1)), width)
   def randomClock():          ConcreteClock = ConcreteClock(randomBigInt(1))
 }

[Chick Markley]

I have opened an issue firrtl-interpreter #18. A fix will be coming shortly