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-rw-r--r--src/arch/riscv/include/bits/strings.h91
1 files changed, 91 insertions, 0 deletions
diff --git a/src/arch/riscv/include/bits/strings.h b/src/arch/riscv/include/bits/strings.h
new file mode 100644
index 000000000..dd6d458b2
--- /dev/null
+++ b/src/arch/riscv/include/bits/strings.h
@@ -0,0 +1,91 @@
+#ifndef _BITS_STRINGS_H
+#define _BITS_STRINGS_H
+
+/** @file
+ *
+ * String functions
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+extern __asmcall unsigned long riscv_ffs ( unsigned long value );
+extern __asmcall unsigned long riscv_fls ( unsigned long value );
+
+/**
+ * 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 riscv_ffs ( value );
+}
+
+/**
+ * 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 low = value;
+ unsigned long high;
+
+ /* Check machine word size */
+ if ( sizeof ( value ) > sizeof ( low ) ) {
+ /* 32-bit */
+ high = ( value >> 32 );
+ if ( low ) {
+ return ( __ffsl ( low ) );
+ } else if ( high ) {
+ return ( 32 + __ffsl ( high ) );
+ } else {
+ return 0;
+ }
+ } else {
+ /* 64-bit */
+ return ( __ffsl ( low ) );
+ }
+}
+
+/**
+ * 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 riscv_fls ( 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 long low = value;
+ unsigned long high;
+
+ /* Check machine word size */
+ if ( sizeof ( value ) > sizeof ( low ) ) {
+ /* 32-bit */
+ high = ( value >> 32 );
+ if ( high ) {
+ return ( 32 + __flsl ( high ) );
+ } else if ( low ) {
+ return ( __flsl ( low ) );
+ } else {
+ return 0;
+ }
+ } else {
+ /* 64-bit */
+ return ( __flsl ( low ) );
+ }
+}
+
+#endif /* _BITS_STRINGS_H */