34 lines
410 B
Go
34 lines
410 B
Go
//+build !go1.9
|
|
|
|
package fstests
|
|
|
|
func leadingZeros64(x uint64) int {
|
|
var n uint64 = 64
|
|
|
|
if y := x >> 32; y != 0 {
|
|
n = n - 32
|
|
x = y
|
|
}
|
|
if y := x >> 16; y != 0 {
|
|
n = n - 16
|
|
x = y
|
|
}
|
|
if y := x >> 8; y != 0 {
|
|
n = n - 8
|
|
x = y
|
|
}
|
|
if y := x >> 4; y != 0 {
|
|
n = n - 4
|
|
x = y
|
|
}
|
|
if y := x >> 2; y != 0 {
|
|
n = n - 2
|
|
x = y
|
|
}
|
|
if y := x >> 1; y != 0 {
|
|
return int(n - 2)
|
|
}
|
|
|
|
return int(n - x)
|
|
}
|