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We propose a partitioned real-time asymmetric architecture (PaRTAA) specifically designed for mixed-criticality airborne systems, featuring robust partitioning within processing elements for establishing isolation between tasks with varying criticality. In contrast, a partitioned uniprocessor offers efficient resource utilization at the cost of limited scalability. An asymmetric multiprocessor architecture offers hardware-based isolation at the cost of underutilized hardware resources, and the inter-core communication mechanism is often a single point of failure in such architectures. Isolation can be achieved with software-based solutions or can be enforced by a hardware level partitioning. Mixed-criticality systems, where multiple systems with varying criticality-levels share a single hardware platform, require isolation between tasks with different criticality-levels. While this specific bundling algorithm is too simple to provide a real-world benefit, it highlights the potential that further work on bundling algorithms can unlock. It looks for branches and bundles the basic blocks on each path of the branch. We present a simple bundling algorithm plugged into the single-path code generator. It can also support different bundling algorithms, which allows changing algorithms without having to edit other parts of the compiler. In this paper, we present a single-path code generation technique with support for dual-issue pipelines. This limitation is unfortunate, as single-path code inherently possesses a high degree of instruction-level parallelism.

While Patmos’ compiler can already produce single-path code, it does not assign any instructions to the second issue-slot.

This technique produces code that always follows the same trace of instructions. A compiler generates highly predictable programs by generating single-path code.

Executing instructions in the second issue slot is a predictable way to increase the throughput of a processor, but without dedicated support from the compiler, this benefit cannot be unlocked. One such feature is its dual-issue pipeline, which can issue and execute bundles of up to two instructions at a time. Designed for real-time systems, the Patmos instruction-set architecture’s features ensure a high degree of predictability.