diff options
Diffstat (limited to 'src/arch/riscv/include/bits/strings.h')
-rw-r--r-- | src/arch/riscv/include/bits/strings.h | 91 |
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 */ |