[Qemu-devel] [PATCH v4 1/8] qemu-common: add QEMU_ALIGN_DOWN() and QEMU_ALIGN_UP() macros

[Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>]

Add macros for aligning a number to a multiple, for example:

QEMU_ALIGN_DOWN(500, 2000) = 0
QEMU_ALIGN_UP(500, 2000) = 2000

Since ALIGN_UP() is a common macro name use the QEMU_* namespace prefix.
Hopefully this will protect us from included headers that leak something
with a similar name.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
 qemu-common.h |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/qemu-common.h b/qemu-common.h
index 2ce47aa..44870fe 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -341,6 +341,12 @@ static inline uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)
     return res.ll;
 }
 
+/* Round number down to multiple */
+#define QEMU_ALIGN_DOWN(n, m) ((n) / (m) * (m))
+
+/* Round number up to multiple */
+#define QEMU_ALIGN_UP(n, m) QEMU_ALIGN_DOWN((n) + (m) - 1, (m))
+
 #include "module.h"
 
 #endif
-- 
1.7.7.1