This adds a helper to get closest bigger power-of-two value.
Signed-off-by: Alexey Kardashevskiy <[email protected]>
---
It is a log2 of round up to power of two. Is there anything like this
in QEMU already? Any better name than up_pow_of_two()?
I'll use this little helper later to calculate a DMA window shift as
POWERPC PAPR architecture operates with shifts rather than bytes or TCE entries.
Thanks!
---
include/qemu/host-utils.h | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h
index d4f21c9..b1ad164 100644
--- a/include/qemu/host-utils.h
+++ b/include/qemu/host-utils.h
@@ -361,6 +361,17 @@ static inline int ctpop64(uint64_t val)
#endif
}
+static inline int up_pow_of_two(uint64_t x)
+{
+ int m = 63 - clz64(x);
+
+ if ((1ULL << m) == x) {
+ return m;
+ }
+
+ return m + 1;
+}
+
/* Host type specific sizes of these routines. */
#if ULONG_MAX == UINT32_MAX
--
2.0.0
