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-rw-r--r--qemu/roms/ipxe/src/arch/i386/include/bits/strings.h50
1 files changed, 50 insertions, 0 deletions
diff --git a/qemu/roms/ipxe/src/arch/i386/include/bits/strings.h b/qemu/roms/ipxe/src/arch/i386/include/bits/strings.h
new file mode 100644
index 000000000..092bcb593
--- /dev/null
+++ b/qemu/roms/ipxe/src/arch/i386/include/bits/strings.h
@@ -0,0 +1,50 @@
+#ifndef _BITS_STRINGS_H
+#define _BITS_STRINGS_H
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/**
+ * 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 ) {
+ long msb_minus_one;
+
+ /* If the input value is zero, the BSR instruction returns
+ * ZF=1 and leaves an undefined value in the output register.
+ * Perform this check in C rather than asm so that it can be
+ * omitted in cases where the compiler is able to prove that
+ * the input is non-zero.
+ */
+ if ( value ) {
+ __asm__ ( "bsrl %1, %0"
+ : "=r" ( msb_minus_one )
+ : "rm" ( value ) );
+ return ( msb_minus_one + 1 );
+ } 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 __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 */