Add RISC-V instruction disassembler

rocket/src/main/scala/util.scala

@@ -1,6 +1,7 @@
 package rocket
 
 import Chisel._
+import scala.math._
 
 object Util
 {
@@ -24,6 +25,77 @@ object AVec
     tabulate(n1)(i1 => tabulate(n2)(f(i1, _)))
 }
 
+object Str
+{
+  def apply(s: String): Bits = {
+    var i = BigInt(0)
+    require(s.forall(validChar _))
+    for (c <- s)
+      i = (i << 8) | c
+    Lit(i, s.length*8){Bits()}
+  }
+  def apply(x: Char): Bits = {
+    require(validChar(x))
+    Lit(x, 8){Bits()}
+  }
+  def apply(x: UFix): Bits = apply(x, 10)
+  def apply(x: UFix, radix: Int): Bits = {
+    val rad = UFix(radix)
+    val digs = digits(radix)
+    val w = x.getWidth
+    require(w > 0)
+
+    var q = x
+    var s = digs(q % rad)
+    for (i <- 1 until ceil(log(2)/log(radix)*w).toInt) {
+      q = q / rad
+      s = Cat(Mux(Bool(radix == 10) && q === UFix(0), Str(' '), digs(q % rad)), s)
+    }
+    s
+  }
+  def apply(x: Fix): Bits = apply(x, 10)
+  def apply(x: Fix, radix: Int): Bits = {
+    val neg = x < Fix(0)
+    val abs = Mux(neg, -x, x).toUFix
+    if (radix != 10) {
+      Cat(Mux(neg, Str('-'), Str(' ')), Str(abs, radix))
+    } else {
+      val rad = UFix(radix)
+      val digs = digits(radix)
+      val w = abs.getWidth
+      require(w > 0)
+
+      var q = abs
+      var s = digs(q % rad)
+      var needSign = neg
+      for (i <- 1 until ceil(log(2)/log(radix)*w).toInt) {
+        q = q / rad
+        val placeSpace = q === UFix(0)
+        val space = Mux(needSign, Str('-'), Str(' '))
+        needSign = needSign && !placeSpace
+        s = Cat(Mux(placeSpace, space, digs(q % rad)), s)
+      }
+      Cat(Mux(needSign, Str('-'), Str(' ')), s)
+    }
+  }
+
+  def bigIntToString(x: BigInt): String = {
+    val s = new StringBuilder
+    var b = x
+    while (b != 0) {
+      s += (x & 0xFF).toChar
+      b = b >> 8
+    }
+    s.toString
+  }
+
+  private def digit(d: Int): Char = (if (d < 10) '0'+d else 'a'-10+d).toChar
+  private def digits(radix: Int): Vec[Bits] =
+    AVec((0 until radix).map(i => Str(digit(i))))
+
+  private def validChar(x: Char) = x == (x & 0xFF)
+}
+
 object Split
 {
   // is there a better way to do do this?