Utilities: Add ACPI_IS_POWER_OF_TWO()

This patch adds a macro ACPI_IS_POWER_OF_TWO, which can be used to detect if a number is a power of two. Lv Zheng. Signed-off-by: Lv Zheng <lv.zheng@intel.com>
acpica · Mar 15, 2016 · cbcb775 · cbcb775
1 parent e81ceda
commit cbcb775
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/source/include/acmacros.h b/source/include/acmacros.h
@@ -336,6 +336,10 @@
 
 #define ACPI_IS_MISALIGNED(value)           (((ACPI_SIZE) value) & (sizeof(ACPI_SIZE)-1))
 
+/* Generic (power-of-two) rounding */
+
+#define ACPI_IS_POWER_OF_TWO(a)             (((a) & ((a) - 1)) == 0)
+
 /*
  * Bitmask creation
  * Bit positions start at zero.