Exception delivery is the responsibility of the matching chk.s instruction.
- When encountered, chk.s calls the operating system routine if the target register is marked (i.e, if the corresponding token bit is set), and does nothing otherwise.
Whether the chk.s instruction will be encountered may depend on the outcome of the branch instruction.
? Thus, it may happen that an exception detected by ld.s is never delivered.
Speculative loading with ld.s/chk.s machine level instructions resembles the TRY/CATCH statements in some high-level programming languages (e.g., Java).