diff options
author | Yang Zhang <yang.z.zhang@intel.com> | 2015-08-28 09:58:54 +0800 |
---|---|---|
committer | Yang Zhang <yang.z.zhang@intel.com> | 2015-09-01 12:44:00 +0800 |
commit | e44e3482bdb4d0ebde2d8b41830ac2cdb07948fb (patch) | |
tree | 66b09f592c55df2878107a468a91d21506104d3f /qemu/roms/ipxe/src/arch/i386/include/bits/strings.h | |
parent | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (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/i386/include/bits/strings.h')
-rw-r--r-- | qemu/roms/ipxe/src/arch/i386/include/bits/strings.h | 50 |
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 */ |