Supporting speculative modification in a data cache

A method of managing speculative data modifications in a data cache, said method comprising:

• in response to a speculative modification to data in a cache line, setting a state indicator of said cache line to a speculative state;
• if said speculative modification to said data is desired to be made permanent, changing said state indicator to a first state in response to a first operation performed upon reaching a particular instruction boundary during speculative execution of instructions, wherein said first state is a dirty state;
• and
• if said speculative modification to said data is desired to be undone, changing said state indicator of said cache line to a second state in response to a second operation performed upon failing to reach said particular instruction boundary during speculative execution of instructions.

A method of managing speculative data modifications in a speculative cache buffer, said method comprising:

• receiving from a data cache a cache line in a speculative state and having speculative modification to the data within said cache line;
• setting a state indicator of said cache line to a speculative state in said speculative cache buffer;
• if said speculative modification to said data is desired to be made permanent, changing said state indicator to a first state in response to a first operation performed upon reaching a particular instruction boundary during speculative execution of instructions, wherein said first state is a dirty state;
• and
• if said speculative modification to said data is desired to be undone, changing said state indicator of said cache line to a second state in response to a second operation performed upon failing to reach said particular instruction boundary during speculative execution of instructions.

A method of managing speculative data modifications in a speculative cache buffer, said method comprising:

• receiving from a data cache a cache line in response to a speculative modification of data in said cache line within said data cache;
• setting a state indicator of said cache line to a commit-kill state in said speculative cache buffer;
• if said speculative modification to said data is desired to be made permanent, changing said state indicator to a first state in response to a first operation performed upon reaching a particular instruction boundary during speculative execution of instructions;
• and
• if said speculative modification to said data is desired to be undone, changing said state indicator of said cache line to a second state in response to a second operation performed upon failing to reach said particular instruction boundary during speculative execution of instructions.