Convert a HEXADECIMAL value into a FLOAT

float2hex.php

<?php declare(strict_types=1);
/**
 * @param float $value
 *
 * @return string
 */
function float2hex(float $value): string
{
    $pack = pack('f', $value);
    $hex = '';

    for ($i = strlen($pack) - 1; $i >= 0; --$i) {
        $hex .= str_pad(dechex(ord($pack[$i])), 2, '0', STR_PAD_LEFT);
    }

    return strtoupper($hex);
}

hex2float.php

<?php declare(strict_types=1);
/**
 * @param string $hex
 *
 * @return float
 */
function hexfloat(string $hex): float
{
    $dec = hexdec($hex);

    if ($dec === 0) {
        return 0;
    }

    $sup = 1 << 23;
    $x = ($dec & ($sup - 1)) + $sup * ($dec >> 31 | 1);
    $exp = ($dec >> 23 & 0xFF) - 127;
    $sign = ($dec & 0x80000000) ? -1 : 1;

    return $sign * $x * pow(2, $exp - 23);
}

rand-float.php

<?php declare(strict_types=1);
/**
 * @param float $min
 * @param float $max
 * @param int $decimals = 6
 *
 * @return float
 */
function rand_float(float $min, float $max, int $decimals = 6): float
{
    $decimals = intval('1'.str_repeat('0', $decimals));

    return mt_rand(intval($min * $decimals), intval($max * $decimals)) / $decimals;
}