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[Qemu-devel] [PATCH 1/5] BIT_RANGE convenience macro
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From: |
Dr. David Alan Gilbert (git) |
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Subject: |
[Qemu-devel] [PATCH 1/5] BIT_RANGE convenience macro |
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Date: |
Thu, 16 Jun 2016 18:12:09 +0100 |
From: "Dr. David Alan Gilbert" <address@hidden>
e.g. BIT_RANGE(15, 0) gives 0xff00
Suggested by: Paolo Bonzini <address@hidden>
Signed-off-by: Dr. David Alan Gilbert <address@hidden>
---
include/qemu/bitops.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/include/qemu/bitops.h b/include/qemu/bitops.h
index 755fdd1..e411688 100644
--- a/include/qemu/bitops.h
+++ b/include/qemu/bitops.h
@@ -23,6 +23,9 @@
#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
#define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
+/* e.g. BIT_RANGE(15, 0) -> 0xff00 */
+#define BIT_RANGE(hb, lb) ((2ull << (hb)) - (1ull << (lb)))
+
/**
* set_bit - Set a bit in memory
--
2.7.4