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[v7,01/12] bitops: Add MAKE_64BIT_MASK macro

Message ID 45fc995a0bc77763e295e5d25fba2dacac3997d5.1466626975.git.alistair.francis@xilinx.com (mailing list archive)
State New, archived
Headers show

Commit Message

Alistair Francis June 22, 2016, 8:23 p.m. UTC 
Add a macro that creates a 64bit value which has length number of ones
shifted across by the value of shift.

Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
---
V7:
 - Fixup commit typo
 - Use the method from deposit64()
V5:
 - Re-write to a 64-bit mask instead of ONES()
 - Re-order this patch in the series

 include/qemu/bitops.h | 3 +++
 1 file changed, 3 insertions(+)

Comments

Peter Maydell June 23, 2016, 12:14 p.m. UTC | #1 
On 22 June 2016 at 21:23, Alistair Francis <alistair.francis@xilinx.com> wrote:
> Add a macro that creates a 64bit value which has length number of ones
> shifted across by the value of shift.
>
> Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM
diff mbox

Patch

diff --git a/include/qemu/bitops.h b/include/qemu/bitops.h
index 15418a8..98fb005 100644
--- a/include/qemu/bitops.h
+++ b/include/qemu/bitops.h
@@ -24,6 +24,9 @@ 
 #define BIT_WORD(nr)            ((nr) / BITS_PER_LONG)
 #define BITS_TO_LONGS(nr)       DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
 
+#define MAKE_64BIT_MASK(shift, length) \
+    (((~0ULL) >> (64 - (length))) << (shift))
+
 /**
  * set_bit - Set a bit in memory
  * @nr: the bit to set