GameBoy\Opcode::opcode189 PHP Method

    public static function opcode189(Core $core)
    {
        $dirtySum = $core->registerA - ($core->registersHL & 0xff);
        $core->FHalfCarry = ($core->unsbtub($dirtySum) & 0xf) > ($core->registerA & 0xf);
        $core->FCarry = $dirtySum < 0;
        $core->FZero = $dirtySum == 0;
        $core->FSubtract = true;
    }