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@@ -600,6 +600,39 @@ explicitly. # much. The correct choice will depend on what you're writing up, and # your own personal preference. +There exist a multitude of formal verification tools designed to describe either +the semantics of ISA instructions or prove the correctness of algorithms. This +section describes some of the most significant work in the field and how the +design of AMPSL improves upon it. + +** Sail + +Sail [cite:@10.1145/3290384] is a language for describing the instruction-set +architecture semantics of processors. It has a syntax similar to the pseudocode +specification of architectures and a first-order type system with dependent +bitvector and numeric types. It is officially used by +[cite/t:@riscv/spec-20191213] to specify the concurrent memory semantics of the +RISC-V architecture. + +Sail has many different backends available, including sequential emulators, +concurrency models and theorem-prover definitions. Further, there are tools to +automatically translate documents from the Arm Specification Language into Sail +(FIXME: cite). + +Despite the many advantages of Sail over other solutions, using Sail in this +project is not suitable for a number of reasons. First is the poor or +nonexistent documentation of the Sail theorem-proving backends. Trying to decode +the output of these tools, given that the input for the RISC-V model is 1.2MiB, +would be time consuming. + +Another reason to avoid Sail is the unnecessary complexity in modelling the ISA +semantics. Sail attempts to model the full complexity of the semantics, +particularly in the face of concurrent memory access. This complexity is +unnecessary for the Arm M-profile architecture, as it has a single thread of +execution. This makes the semantics much simpler to reason about. + +** ? + * Design of AMPSL and its Semantics # This chapter may be called something else... but in general the |