math64: Add mul_u64_u32_shr()

[cascardo/linux.git] / include / linux / math64.h

diff --git a/include/linux/math64.h b/include/linux/math64.h
index 69ed5f5..c45c089 100644 (file)
--- a/include/linux/math64.h
+++ b/include/linux/math64.h
@@ -133,4 +133,34 @@ __iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
        return ret;
 }
 
+#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
+
+#ifndef mul_u64_u32_shr
+static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift)
+{
+       return (u64)(((unsigned __int128)a * mul) >> shift);
+}
+#endif /* mul_u64_u32_shr */
+
+#else
+
+#ifndef mul_u64_u32_shr
+static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift)
+{
+       u32 ah, al;
+       u64 ret;
+
+       al = a;
+       ah = a >> 32;
+
+       ret = ((u64)al * mul) >> shift;
+       if (ah)
+               ret += ((u64)ah * mul) << (32 - shift);
+
+       return ret;
+}
+#endif /* mul_u64_u32_shr */
+
+#endif
+
 #endif /* _LINUX_MATH64_H */