Arm® A64 Instruction Set Architecture: Armv8, for Armv8-A architecture profile

SSBB

Speculative Store Bypass Barrier is a memory barrier which prevents speculative loads from bypassing earlier stores to the same virtual address under certain conditions.

The semantics of the Speculative Store Bypass Barrier are:

• When a load to a location appears in program order after the SSBB, then the load does not speculatively read an entry earlier in the coherence order for that location than the entry generated by the latest store satisfying all of the following conditions:
  • The store is to the same location as the load.
  • The store uses the same virtual address as the load.
  • The store appears in program order before the SSBB.
• When a load to a location appears in program order before the SSBB, then the load does not speculatively read data from any store satisfying all of the following conditions:
  • The store is to the same location as the load.
  • The store uses the same virtual address as the load.
  • The store appears in program order after the SSBB.

// No additional decoding required

SpeculativeStoreBypassBarrierToVA();