blob: 6b4bb8f030753ee34170dd71c1c139b0c6d66d6b (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
|
// SPDX-License-Identifier: Apache-2.0
package chisel3.util
import chisel3._
/** Map each bit to the logical OR of itself and all bits with lower index
*
* Here `scanLeft` means "start from the left and iterate to the right, where left is the lowest index", a common operation on arrays and lists.
* @example {{{
* scanLeftOr("b00001000".U(8.W)) // Returns "b11111000".U
* scanLeftOr("b00010100".U(8.W)) // Returns "b11111100".U
* scanLeftOr("b00000000".U(8.W)) // Returns "b00000000".U
* }}}
*/
object scanLeftOr {
def apply(data: UInt): UInt = {
val width = data.widthOption match {
case Some(w) => w
case None => throw new IllegalArgumentException("Cannot call scanLeftOr on data with unknown width.")
}
def helper(s: Int, x: UInt): UInt =
if (s >= width) x else helper(s + s, x | (x << s)(width - 1, 0))
helper(1, data)(width - 1, 0)
}
}
/** Map each bit to the logical OR of itself and all bits with higher index
*
* Here `scanRight` means "start from the right and iterate to the left, where right is the highest index", a common operation on arrays and lists.
* @example {{{
* scanRightOr("b00001000".U) // Returns "b00001111".U
* scanRightOr("b00010100".U) // Returns "b00011111".U
* scanRightOr("b00000000".U) // Returns "b00000000".U
* }}}
*/
object scanRightOr {
def apply(data: UInt): UInt = {
val width = data.widthOption match {
case Some(w) => w
case None => throw new IllegalArgumentException("Cannot call scanRightOr on data with unknown width.")
}
def helper(s: Int, x: UInt): UInt =
if (s >= width) x else helper(s + s, x | (x >> s))
helper(1, data)(width - 1, 0)
}
}
|
