utils scaladoc examples for BitPat through CircuitMath (#398)

Add examples for utils, move examples from individual apply methods to class overview scaladoc

1 files changed, 14 insertions, 5 deletions

diff --git a/src/main/scala/chisel3/util/BitPat.scala b/src/main/scala/chisel3/util/BitPat.scala
index 9c9909cd..add40f79 100644
--- a/src/main/scala/chisel3/util/BitPat.scala
+++ b/src/main/scala/chisel3/util/BitPat.scala
@@ -35,7 +35,7 @@ object BitPat {
   }
 
   /** Creates a [[BitPat]] literal from a string.
-   *
+    *
     * @param n the literal value as a string, in binary, prefixed with 'b'
     * @note legal characters are '0', '1', and '?', as well as '_' and white
     * space (which are ignored)
@@ -45,7 +45,12 @@ object BitPat {
     new BitPat(bits, mask, width)
   }
 
-  /** Creates a [[BitPat]] of all don't cares of the specified bitwidth. */
+  /** Creates a [[BitPat]] of all don't cares of the specified bitwidth.
+    *
+    * @example {{{
+    * val myDontCare = BitPat.dontCare(4)  // equivalent to BitPat("b????")
+    * }}}
+    */
   def dontCare(width: Int): BitPat = BitPat("b" + ("?" * width))
 
   @deprecated("Use BitPat.dontCare", "chisel3")
@@ -73,10 +78,14 @@ object BitPat {
   }
 }
 
-// TODO: Break out of Core? (this doesn't involve FIRRTL generation)
 /** Bit patterns are literals with masks, used to represent values with don't
-  * cares. Equality comparisons will ignore don't care bits (for example,
-  * BitPat(0b10?1) === 0b1001.asUInt and 0b1011.asUInt.
+  * care bits. Equality comparisons will ignore don't care bits.
+  *
+  * @example {{{
+  * "b10101".U === BitPat("b101??") // evaluates to true.B
+  * "b10111".U === BitPat("b101??") // evaluates to true.B
+  * "b10001".U === BitPat("b101??") // evaluates to false.B
+  * }}}
   */
 sealed class BitPat(val value: BigInt, val mask: BigInt, width: Int) {
   def getWidth: Int = width