| private static computeSquareIndex ( string $exponent_remaining, integer $actual_index, integer $exp_scale, integer $inner_scale ) : string | ||
| $exponent_remaining | string | |
| $actual_index | integer | |
| $exp_scale | integer | Number of $exponent's significative digits |
| $inner_scale | integer | ceil($exp_scale*log(10)/log(2))+1; |
| return | string | |
private static function computeSquareIndex($exponent_remaining, $actual_index, $exp_scale, $inner_scale)
{
$actual_rt = bcpow('0.5', $actual_index, $exp_scale);
$r = bcsub($exponent_remaining, $actual_rt, $inner_scale);
while (bccomp($r, 0, $exp_scale) === -1) {
++$actual_index;
$actual_rt = bcmul('0.5', $actual_rt, $inner_scale);
$r = bcsub($exponent_remaining, $actual_rt, $inner_scale);
}
return [$actual_index, $r];
}