What are the best practices for accurately converting hexadecimal values to signed integers in PHP, taking into account 2's complement representation?

When converting hexadecimal values to signed integers in PHP, it is important to consider the 2's complement representation used for negative numbers. To accurately convert a hexadecimal value to a signed integer, you need to check if the most significant bit (MSB) is set, indicating a negative number in 2's complement. If it is set, you need to perform additional calculations to correctly interpret the value as a signed integer. 

function hexToSignedInt($hex) {
    $int = hexdec($hex);
    
    // Check if MSB is set
    if ($int & 0x80000000) {
        $int = -((~$int & 0xFFFFFFFF) + 1);
    }
    
    return $int;
}

// Example usage
$hexValue = 'FFFFFFF6'; // Represents -10 in 2's complement
$signedInt = hexToSignedInt($hexValue);
echo $signedInt; // Output: -10

Keywords

PHP hexadecimal signed integers 2's complement conversion

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