isqrt.h File Reference

Integer square root. More...

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
	FILE_SECBOOT (PERMITTED)
unsigned long	isqrt (unsigned long value)
	Find integer square root.

Detailed Description

Integer square root.

Definition in file isqrt.h.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

FILE_SECBOOT()

FILE_SECBOOT

(

PERMITTED

)

References value.

isqrt()

unsigned long isqrt ( unsigned long value )

extern

Find integer square root.

Parameters

value	Value
isqrt	Integer square root of value

Definition at line 41 of file isqrt.c.

                                            {
        unsigned long result = 0;
        unsigned long bit = ( 1UL << ( ( 8 * sizeof ( bit ) ) - 2 ) );
 
        while ( bit > value )
                bit >>= 2;
        while ( bit ) {
                if ( value >= ( result + bit ) ) {
                        value -= ( result + bit );
                        result = ( ( result >> 1 ) + bit );
                } else {
                        result >>= 1;
                }
                bit >>= 2;
        }
        return result;
}

References bit, result, and value.

Referenced by math_test_exec(), and profile_stddev().