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// See LICENSE for license details.
/** Circuit-land math operations.
*/
package chisel.util
import 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)
}
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