Module core::core_arch::aarch64::tme

🔬This is a nightly-only experimental API. (stdsimd #48556)

Available on AArch64 only.

ARM’s Transactional Memory Extensions (TME).

This CPU feature is available on Aarch64 - A architecture profile. This feature is in the non-neon feature set. TME specific vendor documentation can be found TME Intrinsics Introduction.

The reference is ACLE Q4 2019.

ACLE has a section for TME extensions and state masks for aborts and failure codes. ARM A64 Architecture Register Datasheet also describes possible failure code scenarios.

Constants

• _TMFAILURE_CNCLExperimental
  Transaction executed a TCANCEL instruction
• _TMFAILURE_DBGExperimental
  Transaction aborted due to a debug trap.
• _TMFAILURE_ERRExperimental
  Transaction aborted because a non-permissible operation was attempted
• _TMFAILURE_IMPExperimental
  Fallback error type for any other reason
• _TMFAILURE_INTExperimental
  Transaction failed from interrupt
• _TMFAILURE_MEMExperimental
  Transaction aborted because a conflict occurred
• _TMFAILURE_NESTExperimental
  Transaction aborted due to transactional nesting level was exceeded
• _TMFAILURE_REASONExperimental
  Extraction mask for failure reason
• _TMFAILURE_RTRYExperimental
  Transaction retry is possible.
• _TMFAILURE_SIZEExperimental
  Transaction aborted due to read or write set limit was exceeded
• _TMFAILURE_TRIVIALExperimental
  Indicates a TRIVIAL version of TM is available
• _TMSTART_SUCCESSExperimental
  Transaction successfully started.

Functions

• __tcancel^⚠Experimentaltme
  Cancels the current transaction and discards all state modifications that were performed transactionally.
• __tcommit^⚠Experimentaltme
  Commits the current transaction. For a nested transaction, the only effect is that the transactional nesting depth is decreased. For an outer transaction, the state modifications performed transactionally are committed to the architectural state.
• __tstart^⚠Experimentaltme
  Starts a new transaction. When the transaction starts successfully the return value is 0. If the transaction fails, all state modifications are discarded and a cause of the failure is encoded in the return value.
• __ttest^⚠Experimentaltme
  Tests if executing inside a transaction. If no transaction is currently executing, the return value is 0. Otherwise, this intrinsic returns the depth of the transaction.
• aarch64_tcancel 🔒 ^⚠Experimental
• aarch64_tcommit 🔒 ^⚠Experimental
• aarch64_tstart 🔒 ^⚠Experimental
• aarch64_ttest 🔒 ^⚠Experimental