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-rw-r--r--lib/int_sqrt.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/lib/int_sqrt.c b/lib/int_sqrt.c
index e2d329099bf7..14436f4ca6bd 100644
--- a/lib/int_sqrt.c
+++ b/lib/int_sqrt.c
@@ -38,3 +38,33 @@ unsigned long int_sqrt(unsigned long x)
return y;
}
EXPORT_SYMBOL(int_sqrt);
+
+#if BITS_PER_LONG < 64
+/**
+ * int_sqrt64 - strongly typed int_sqrt function when minimum 64 bit input
+ * is expected.
+ * @x: 64bit integer of which to calculate the sqrt
+ */
+u32 int_sqrt64(u64 x)
+{
+ u64 b, m, y = 0;
+
+ if (x <= ULONG_MAX)
+ return int_sqrt((unsigned long) x);
+
+ m = 1ULL << (fls64(x) & ~1ULL);
+ while (m != 0) {
+ b = y + m;
+ y >>= 1;
+
+ if (x >= b) {
+ x -= b;
+ y += m;
+ }
+ m >>= 2;
+ }
+
+ return y;
+}
+EXPORT_SYMBOL(int_sqrt64);
+#endif