isqrt.c File Reference

Integer square root. More...

#include <ipxe/isqrt.h>

Go to the source code of this file.

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

Detailed Description

Integer square root.

Definition in file isqrt.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

isqrt()

unsigned long isqrt

(

unsigned long

value

)

Find integer square root.

Parameters

value	Value
isqrt	Integer square root of value

Definition at line 40 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().