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authorJim Lawson2016-07-06 10:01:23 -0700
committerJim Lawson2016-07-18 15:17:56 -0700
commitc5f9ea3133ef363ff8944e17d94fea79767b6bed (patch)
treecc80a6df1eb58f0feaf9f138eb7fe261ccda4ea2 /src/main/scala/chisel3/util/CircuitMath.scala
parent53813f61b7dfe246d214ab966739d01c65c8ecb0 (diff)
Rename "Chisel" to "chisel3" (only git mv).
Diffstat (limited to 'src/main/scala/chisel3/util/CircuitMath.scala')
-rw-r--r--src/main/scala/chisel3/util/CircuitMath.scala26
1 files changed, 26 insertions, 0 deletions
diff --git a/src/main/scala/chisel3/util/CircuitMath.scala b/src/main/scala/chisel3/util/CircuitMath.scala
new file mode 100644
index 00000000..06cab903
--- /dev/null
+++ b/src/main/scala/chisel3/util/CircuitMath.scala
@@ -0,0 +1,26 @@
+// See LICENSE for license details.
+
+/** Circuit-land math operations.
+ */
+
+package Chisel
+
+/** Compute Log2 with truncation of a UInt in hardware using a Mux Tree
+ * An alternative interpretation is it computes the minimum number of bits needed to represent x
+ * @example
+ * {{{ data_out := Log2(data_in) }}}
+ * @note Truncation is used so Log2(UInt(12412)) = 13*/
+object Log2 {
+ /** Compute the Log2 on the least significant n bits of x */
+ def apply(x: Bits, width: Int): UInt = {
+ if (width < 2) {
+ UInt(0)
+ } else if (width == 2) {
+ x(1)
+ } else {
+ Mux(x(width-1), UInt(width-1), apply(x, width-1))
+ }
+ }
+
+ def apply(x: Bits): UInt = apply(x, x.getWidth)
+}