Patchwork [v2,1/8] qemu-common: add QEMU_ALIGN_DOWN() and QEMU_ALIGN_UP() macros

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Submitter Stefan Hajnoczi
Date Nov. 17, 2011, 1:40 p.m.
Message ID <1321537232-799-2-git-send-email-stefanha@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/126220/
State New
Headers show

Comments

Stefan Hajnoczi - Nov. 17, 2011, 1:40 p.m.
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(-)

Patch

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