Converting ARM DS Startup Files to IAR-Compatible Format for Cortex-R52

ARM Cortex-R52 Startup File Conversion Challenges Between ARM DS and IAR Toolchains

The process of converting a startup assembly file from ARM DS (Arm Development Studio) to an IAR-compatible format for the Cortex-R52 processor involves understanding the differences in syntax, directives, and toolchain-specific requirements between the two environments. The Cortex-R52 is a high-performance, real-time processor core designed for safety-critical applications, and its startup file is critical for initializing the processor, setting up the memory map, and preparing the environment for the main application. The ARM DS and IAR toolchains, while both supporting ARM architectures, have distinct assembly syntax and linker script requirements, making direct conversion non-trivial.

The ARM DS startup file typically includes assembly directives specific to the ARM toolchain, such as .section, .global, and .word, which may not be directly compatible with IAR’s assembler. Additionally, the IAR toolchain uses its own set of directives and linker configuration files, which must be carefully adapted to ensure proper initialization of the Cortex-R52. This conversion process requires a deep understanding of both toolchains and the Cortex-R52 architecture to ensure that the startup sequence is correctly implemented.

Toolchain-Specific Assembly Syntax and Directive Mismatches

One of the primary challenges in converting an ARM DS startup file to an IAR-compatible format lies in the differences in assembly syntax and directives between the two toolchains. ARM DS uses the ARM Compiler, which supports a specific set of assembly directives and syntax that may not be directly translatable to IAR’s assembler. For example, ARM DS uses .section to define memory sections, while IAR uses SECTION or RSEG. Similarly, ARM DS uses .global to declare global symbols, whereas IAR uses PUBLIC.

Another critical difference is in the way the stack and heap are initialized. ARM DS startup files often include explicit stack and heap setup using directives like .stack and .heap, while IAR typically handles these through linker configuration files (ICF files). This requires careful mapping of memory regions and initialization sequences to ensure that the Cortex-R52’s memory model is correctly set up in the IAR environment.

Additionally, the Cortex-R52’s memory protection unit (MPU) and cache initialization sequences may differ between the two toolchains. ARM DS startup files often include explicit MPU and cache configuration code, which must be adapted to IAR’s syntax and linker requirements. This includes ensuring that the correct memory attributes and access permissions are set up for the Cortex-R52’s memory regions.

Adapting ARM DS Startup Code to IAR Syntax and Linker Configuration

To successfully convert an ARM DS startup file to an IAR-compatible format, the following steps should be taken:

1. Review and Map ARM DS Directives to IAR Equivalents: Begin by reviewing the ARM DS startup file and identifying all assembly directives. Create a mapping of these directives to their IAR equivalents. For example, .section in ARM DS can be replaced with SECTION or RSEG in IAR, and .global can be replaced with PUBLIC.

2. Translate Stack and Heap Initialization: If the ARM DS startup file includes explicit stack and heap setup, this code must be adapted to IAR’s linker configuration file (.icf). Define the stack and heap regions in the .icf file and ensure that the linker script correctly initializes these regions. For example, in IAR, the stack can be defined using the STACK keyword in the .icf file, while the heap can be defined using the HEAP keyword.

3. Adapt MPU and Cache Initialization: The Cortex-R52’s MPU and cache initialization code must be carefully translated to IAR syntax. Ensure that the memory attributes and access permissions are correctly set up in the IAR startup file. This may involve replacing ARM DS-specific MPU configuration code with IAR-compatible assembly instructions.

4. Verify Interrupt Vector Table Setup: The interrupt vector table in the ARM DS startup file must be adapted to IAR’s syntax. Ensure that the vector table is correctly defined and aligned according to IAR’s requirements. For example, IAR uses the SECTION directive to define the vector table section, and the vectors must be aligned to the correct boundary.

5. Test and Validate the Startup Sequence: After converting the startup file, thoroughly test the startup sequence to ensure that the Cortex-R52 is correctly initialized. This includes verifying that the stack, heap, MPU, and cache are properly set up, and that the interrupt vector table is correctly configured. Use debugging tools provided by IAR to step through the startup sequence and validate each step.

6. Optimize for IAR Toolchain: Once the startup file is functional, consider optimizing it for the IAR toolchain. This may involve leveraging IAR-specific features or optimizations that are not available in ARM DS. For example, IAR’s linker script language allows for more fine-grained control over memory regions and initialization sequences, which can be used to further optimize the startup process.

By following these steps, you can successfully convert an ARM DS startup file to an IAR-compatible format for the Cortex-R52 processor. This process requires a deep understanding of both toolchains and the Cortex-R52 architecture, but with careful attention to detail, it is possible to achieve a seamless transition between the two environments.

Detailed Comparison of ARM DS and IAR Assembly Directives

To further aid in the conversion process, the following table provides a detailed comparison of common ARM DS and IAR assembly directives:

This table can serve as a reference when converting ARM DS startup files to IAR-compatible format. By carefully mapping each directive and ensuring that the correct syntax is used, you can avoid common pitfalls and ensure a smooth transition between the two toolchains.

Conclusion

Converting an ARM DS startup file to an IAR-compatible format for the Cortex-R52 processor is a complex but manageable task. By understanding the differences in assembly syntax and directives between the two toolchains, and carefully adapting the startup sequence to IAR’s requirements, you can ensure that the Cortex-R52 is correctly initialized and ready to run your application. The key to success lies in meticulous attention to detail and thorough testing to validate the startup sequence. With the right approach, you can achieve a seamless transition between ARM DS and IAR, enabling you to leverage the strengths of both toolchains in your Cortex-R52 projects.