X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=libringbuffer%2Fbackend_internal.h;h=36d53dfd531357037501a539cd8c991c9d2ca4d9;hb=96e80018cb6ef2098193bd4d8fe724df29f2faf0;hp=f61d1d61bc0a2cce0ca84469aa79093960937e7a;hpb=a3f61e7f689a5fc60b833a773f462989dc6cc78f;p=lttng-ust.git

diff --git a/libringbuffer/backend_internal.h b/libringbuffer/backend_internal.h
index f61d1d61..36d53dfd 100644
--- a/libringbuffer/backend_internal.h
+++ b/libringbuffer/backend_internal.h
@@ -416,6 +416,10 @@ int update_read_sb_index(const struct lttng_ust_lib_ring_buffer_config *config,
 	return 0;
 }
 
+#ifndef inline_memcpy
+#define inline_memcpy(dest, src, n)	memcpy(dest, src, n)
+#endif
+
 /*
  * Use the architecture-specific memcpy implementation for constant-sized
  * inputs, but rely on an inline memcpy for length statically unknown.
@@ -430,4 +434,61 @@ do {								\
 		inline_memcpy(dest, src, __len);		\
 } while (0)
 
+/* arch-agnostic implementation */
+
+static inline int fls(unsigned int x)
+{
+	int r = 32;
+
+	if (!x)
+		return 0;
+	if (!(x & 0xFFFF0000U)) {
+		x <<= 16;
+		r -= 16;
+	}
+	if (!(x & 0xFF000000U)) {
+		x <<= 8;
+		r -= 8;
+	}
+	if (!(x & 0xF0000000U)) {
+		x <<= 4;
+		r -= 4;
+	}
+	if (!(x & 0xC0000000U)) {
+		x <<= 2;
+		r -= 2;
+	}
+	if (!(x & 0x80000000U)) {
+		x <<= 1;
+		r -= 1;
+	}
+	return r;
+}
+
+static inline int get_count_order(unsigned int count)
+{
+	int order;
+
+	order = fls(count) - 1;
+	if (count & (count - 1))
+		order++;
+	return order;
+}
+
+static inline
+unsigned int hweight32(unsigned int value)
+{
+	unsigned int r;
+
+	r = value;
+	r = r - ((r >> 1) & 0x55555555);
+	r = (r & 0x33333333) + ((r >> 2) & 0x33333333);
+	r += r >> 4;
+	r &= 0x0F0F0F0F;
+	r += r >> 8;
+	r += r >> 16;
+	r &= 0x000000FF;
+	return r;
+}
+
 #endif /* _LINUX_RING_BUFFER_BACKEND_INTERNAL_H */