[arm] Split out 32-bit-specific code to arch/arm32

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 85 insertions, 0 deletions

diff --git a/src/arch/arm32/include/bits/strings.h b/src/arch/arm32/include/bits/strings.h
new file mode 100644
index 00000000..adbd5f4b
--- /dev/null
+++ b/src/arch/arm32/include/bits/strings.h
@@ -0,0 +1,85 @@
+#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 __ffsl ( long value ) {
+	unsigned long bits = value;
+	unsigned 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 ( 32 - 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 __ffsll ( long long value ){
+	unsigned long high = ( value >> 32 );
+	unsigned long low = ( value >> 0 );
+
+	if ( low ) {
+		return ( __ffsl ( low ) );
+	} else if ( high ) {
+		return ( 32 + __ffsl ( high ) );
+	} else {
+		return 0;
+	}
+}
+
+/**
+ * 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 ) {
+	unsigned int lz;
+
+	/* Count number of leading zeroes */
+	__asm__ ( "clz %0, %1" : "=r" ( lz ) : "r" ( value ) );
+
+	return ( 32 - 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 __flsll ( long long value ){
+	unsigned long high = ( value >> 32 );
+	unsigned long low = ( value >> 0 );
+
+	if ( high ) {
+		return ( 32 + __flsl ( high ) );
+	} else if ( low ) {
+		return ( __flsl ( low ) );
+	} else {
+		return 0;
+	}
+}
+
+#endif /* _BITS_STRINGS_H */