1 files changed, 69 insertions, 0 deletions
diff --git a/src/arch/arm64/include/bits/strings.h b/src/arch/arm64/include/bits/strings.h
new file mode 100644
index 000000000..d5340f484
--- /dev/null
+++ b/src/arch/arm64/include/bits/strings.h
@@ -0,0 +1,69 @@
+#ifndef _BITS_STRINGS_H
+#define _BITS_STRINGS_H
+
+/** @file
+ *
+ * String functions
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/**
+ * Find first (i.e. least significant) set bit
+ *
+ * @v value		Value
+ * @ret lsb		Least significant bit set in value (LSB=1), or zero
+ */
+static inline __attribute__ (( always_inline )) int __ffsll ( long long value ){
+	unsigned long long bits = value;
+	unsigned long long lsb;
+	unsigned int lz;
+
+	/* Extract least significant set bit */
+	lsb = ( bits & -bits );
+
+	/* Count number of leading zeroes before LSB */
+	__asm__ ( "clz %0, %1" : "=r" ( lz ) : "r" ( lsb ) );
+
+	return ( 64 - lz );
+}
+
+/**
+ * Find first (i.e. least significant) set bit
+ *
+ * @v value		Value
+ * @ret lsb		Least significant bit set in value (LSB=1), or zero
+ */
+static inline __attribute__ (( always_inline )) int __ffsl ( long value ) {
+
+	return __ffsll ( value );
+}
+
+/**
+ * Find last (i.e. most significant) set bit
+ *
+ * @v value		Value
+ * @ret msb		Most significant bit set in value (LSB=1), or zero
+ */
+static inline __attribute__ (( always_inline )) int __flsll ( long long value ){
+	unsigned int lz;
+
+	/* Count number of leading zeroes */
+	__asm__ ( "clz %0, %1" : "=r" ( lz ) : "r" ( value ) );
+
+	return ( 64 - lz );
+}
+
+/**
+ * Find last (i.e. most significant) set bit
+ *
+ * @v value		Value
+ * @ret msb		Most significant bit set in value (LSB=1), or zero
+ */
+static inline __attribute__ (( always_inline )) int __flsl ( long value ) {
+
+	return __flsll ( value );
+}
+
+#endif /* _BITS_STRINGS_H */