Synchronization techniques in a multithreaded environment

A computer system for accessing memory comprising:

• means for establishing an exception indicator for a memory location;
• means for enabling an exception to be raised when the memory location is accessed;
• and
• trap handler means for identifying the exception indicator that has been established for the memory location, for performing processing for read access of the memory location according to the identified exception indicator, and for performing processing for write access of the memory location according to the identified exception indicator, wherein the exception indicator specifies the type of exception processing.

A method in trap handler for handling access to a memory location with an established exception indicator, the trap handler executing when an exception is raised as a result of access to that memory location, the method comprising:

• identifying the exception indicator that has been established for the memory location, the exception indicator specifying the type of exception processing;
• when the access is a read access, performing processing for read access of the memory location according to the identified exception indicator;
• and
• when the access is a write access, performing processing for write access of the memory location according to the identified exception indicator.