Link Stack Repair of Erroneous Speculative Update

A processor comprising:

• a link stack comprising a plurality of entries, each entry operative to store a link address;
• a read circuit configured to speculatively read a first link address from a link stack entry of the link stack;
• a detection circuit configured to generate an indication that a speculative write following the speculative read would overwrite the first link address at the link stack entry
• a link stack restore buffer configured to save the first link address in response to the indication from the detection circuit;
• and
• a write circuit configured to speculatively write a second link address to the link stack entry after the speculative read of the first link address, wherein the first link address of the link stack entry is overwritten by the second link address.

A system for managing a link stack comprising a plurality of entries, each entry operative to store a link address, the system comprising:

• means for speculatively reading a first link address from a link stack entry of the link stack;
• means for generating an indication that a speculative write following the speculative read would overwrite the first link address at the link stack entry;
• buffer means for saving the first link address in response to the indication;
• and
• means for speculatively writing a second link address to the link stack entry after speculatively reading the first link address, wherein the first link address of the link stack entry is overwritten by the second link address.

A non-transitory computer-readable storage medium comprising code, which, when executed by a processor, causes the processor to perform operations for managing a link stack comprising a plurality of entries, each entry operative to store a link address, the non-transitory computer-readable storage medium comprising:

• code for speculatively reading a first link address from a link stack entry of the link stack;
• code for generating an indication that a speculative write following the speculative read would overwrite the first link address at the link stack entry;
• code for saving the first link address in a link stack restore buffer, in response to the indication;
• and
• code for speculatively writing a second link address to the link stack entry after speculatively reading the first link address, wherein the first link address of the link stack entry is overwritten by the second link address.