[Minios-devel] [UNIKRAFT PATCH v6 6/7] arch/arm64: Implement bitops for arm64

[Jia He <justin.he@xxxxxxx>]

Without this patch, compiler will report warning as follows:
  In file included from plat/common/arm/time.c:41:0:
include/uk/bitops.h: In function 'uk_get_count_order':
include/uk/bitops.h:89:10: warning: implicit declaration of function
'ukarch_fls'; did you mean 'ukarch_ffsl'? [-Wimplicit-function-declaration]
  order = ukarch_fls(count);
          ^~~~~~~~~~
          ukarch_ffsl
include/uk/bitops.h: In function 'uk_find_last_bit':
include/uk/bitops.h:154:18: warning: implicit declaration of function
'ukarch_flsl'; did you mean 'ukarch_ffsl'? [-Wimplicit-function-declaration]
    return (bit + ukarch_flsl(mask));
                  ^~~~~~~~~~~
                  ukarch_ffsl

Signed-off-by: Jia He <justin.he@xxxxxxx>
---
V6: change the returned bit postion from [1...32] to [0...31]

 arch/arm/arm64/include/uk/asm/atomic.h | 36 ++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/arch/arm/arm64/include/uk/asm/atomic.h 
b/arch/arm/arm64/include/uk/asm/atomic.h
index 7ee6667..431ac84 100644
--- a/arch/arm/arm64/include/uk/asm/atomic.h
+++ b/arch/arm/arm64/include/uk/asm/atomic.h
@@ -37,6 +37,31 @@
 #error Do not include this header directly
 #endif
 
+/**
+ * ukarch_ffs - find first (lowest) set bit in word.
+ * @word: The word to search
+ *
+ * Returns one plus the index of the least significant 1-bit of x, or
+ * if x is zero, returns zero.
+ * ffs(1)=0, ffs(0x8000000)=31
+ */
+static inline unsigned int ukarch_ffs(unsigned int x)
+{
+       return __builtin_ffs(x) - 1;
+}
+
+/**
+ * ukarch_fls - find last (highest) set bit in word.
+ * @word: The word to search
+ *
+ * Undefined if no bit exists, so code should check against 0 first.
+ * fls(1)=0, fls(0x8000000)=31
+ */
+static inline unsigned int ukarch_fls(unsigned int x)
+{
+       return sizeof(x) * 8 - __builtin_clz(x) - 1;
+}
+
 /**
  * ukarch_ffsl - find first (lowest) set bit in word.
  * @word: The word to search
@@ -68,3 +93,14 @@ static inline unsigned long ukarch_ffsl(unsigned long word)
 
        return 63 - clz;
 }
+
+/**
+ * ukarch_flsl - find last (highest) set bit in word.
+ * @word: The word to search
+ *
+ * Undefined if no bit exists, so code should check against 0 first.
+ */
+static inline unsigned long ukarch_flsl(unsigned long x)
+{
+       return sizeof(x) * 8 - __builtin_clzl(x) - 1;
+}
-- 
2.17.1


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