summaryrefslogtreecommitdiff
path: root/src/main/scala/chisel3/util/Bitwise.scala
diff options
context:
space:
mode:
authorJim Lawson2016-07-06 10:01:23 -0700
committerJim Lawson2016-07-18 15:17:56 -0700
commitc5f9ea3133ef363ff8944e17d94fea79767b6bed (patch)
treecc80a6df1eb58f0feaf9f138eb7fe261ccda4ea2 /src/main/scala/chisel3/util/Bitwise.scala
parent53813f61b7dfe246d214ab966739d01c65c8ecb0 (diff)
Rename "Chisel" to "chisel3" (only git mv).
Diffstat (limited to 'src/main/scala/chisel3/util/Bitwise.scala')
-rw-r--r--src/main/scala/chisel3/util/Bitwise.scala71
1 files changed, 71 insertions, 0 deletions
diff --git a/src/main/scala/chisel3/util/Bitwise.scala b/src/main/scala/chisel3/util/Bitwise.scala
new file mode 100644
index 00000000..239a295e
--- /dev/null
+++ b/src/main/scala/chisel3/util/Bitwise.scala
@@ -0,0 +1,71 @@
+// See LICENSE for license details.
+
+/** Miscellaneous circuit generators operating on bits.
+ */
+
+package Chisel
+
+object FillInterleaved
+{
+ def apply(n: Int, in: UInt): UInt = apply(n, in.toBools)
+ def apply(n: Int, in: Seq[Bool]): UInt = Vec(in.map(Fill(n, _))).toBits
+}
+
+/** Returns the number of bits set (i.e value is 1) in the input signal.
+ */
+object PopCount
+{
+ def apply(in: Iterable[Bool]): UInt = SeqUtils.count(in.toSeq)
+ def apply(in: Bits): UInt = apply((0 until in.getWidth).map(in(_)))
+}
+
+/** Fill fans out a UInt to multiple copies */
+object Fill {
+ /** Fan out x n times */
+ def apply(n: Int, x: UInt): UInt = {
+ n match {
+ case 0 => UInt(width=0)
+ case 1 => x
+ case y if n > 1 =>
+ val p2 = Array.ofDim[UInt](log2Up(n + 1))
+ p2(0) = x
+ for (i <- 1 until p2.length)
+ p2(i) = Cat(p2(i-1), p2(i-1))
+ Cat((0 until log2Up(y + 1)).filter(i => (y & (1 << i)) != 0).map(p2(_)))
+ case _ => throw new IllegalArgumentException(s"n (=$n) must be nonnegative integer.")
+ }
+ }
+ /** Fan out x n times */
+ def apply(n: Int, x: Bool): UInt =
+ if (n > 1) {
+ UInt(0,n) - x
+ } else {
+ apply(n, x: UInt)
+ }
+}
+
+/** Litte/big bit endian convertion: reverse the order of the bits in a UInt.
+*/
+object Reverse
+{
+ private def doit(in: UInt, length: Int): UInt = {
+ if (length == 1) {
+ in
+ } else if (isPow2(length) && length >= 8 && length <= 64) {
+ // This esoterica improves simulation performance
+ var res = in
+ var shift = length >> 1
+ var mask = UInt((BigInt(1) << length) - 1, length)
+ do {
+ mask = mask ^ (mask(length-shift-1,0) << shift)
+ res = ((res >> shift) & mask) | ((res(length-shift-1,0) << shift) & ~mask)
+ shift = shift >> 1
+ } while (shift > 0)
+ res
+ } else {
+ val half = (1 << log2Up(length))/2
+ Cat(doit(in(half-1,0), half), doit(in(length-1,half), length-half))
+ }
+ }
+ def apply(in: UInt): UInt = doit(in, in.getWidth)
+}