The traditional  software method for clearing module interrupt flags in TI’s 8051-based low power wireless  System-on-Chip     (LPW  SoC) devices can unintentionally mask other interrupt flags. Depending on the peripheral and the application, these   masked or missing module interrupts can lead to unexpected system behavior. For example, in the Direct Memory Access (DMA) controller, a missing interrupt flag can freeze a channel until a system restart reinitializes the controller. 
 
Lost interrupts can result from read-modify-write (RMW) operations to clear older interrupt flags in the same module flag register. Examples of these traditional RMW  operations  to  clear  interrupt  flags can  be  found  in  datasheets  and  sample code.  This  design  note  describes  how module  interrupt  flags  can  be  lost  when using  these  operations  and  recommends alternative  code  that  takes  advantage  of the Write-0 design of the module interrupt flag bits.
 
Although  this  note  assumes  a  working knowledge  of  interrupt  programming,  a brief  overview  of  interrupt  flags  prefaces the issue of lost module interrupt flags and its avoidance.

http://www.ti.com/lit/swra303