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authorYang Zhang <yang.z.zhang@intel.com>2015-08-28 09:58:54 +0800
committerYang Zhang <yang.z.zhang@intel.com>2015-09-01 12:44:00 +0800
commite44e3482bdb4d0ebde2d8b41830ac2cdb07948fb (patch)
tree66b09f592c55df2878107a468a91d21506104d3f /qemu/roms/ipxe/src/arch/x86_64/include/bits/strings.h
parent9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (diff)
Add qemu 2.4.0
Change-Id: Ic99cbad4b61f8b127b7dc74d04576c0bcbaaf4f5 Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>
Diffstat (limited to 'qemu/roms/ipxe/src/arch/x86_64/include/bits/strings.h')
-rw-r--r--qemu/roms/ipxe/src/arch/x86_64/include/bits/strings.h42
1 files changed, 42 insertions, 0 deletions
diff --git a/qemu/roms/ipxe/src/arch/x86_64/include/bits/strings.h b/qemu/roms/ipxe/src/arch/x86_64/include/bits/strings.h
new file mode 100644
index 000000000..6ee99a500
--- /dev/null
+++ b/qemu/roms/ipxe/src/arch/x86_64/include/bits/strings.h
@@ -0,0 +1,42 @@
+#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 __flsll ( long long value ){
+ long 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__ ( "bsrq %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 __flsl ( long value ) {
+
+ return __flsll ( value );
+}
+
+#endif /* _BITS_STRINGS_H */