GameBoy\Opcode::opcode254 PHP Method

    public static function opcode254(Core $core)
    {
        $dirtySum = $core->registerA - $core->memoryRead($core->programCounter);
        $core->FHalfCarry = ($core->unsbtub($dirtySum) & 0xf) > ($core->registerA & 0xf);
        $core->FCarry = $dirtySum < 0;
        $core->FZero = $dirtySum == 0;
        $core->programCounter = $core->programCounter + 1 & 0xffff;
        $core->FSubtract = true;
    }