Author: System on Chips

Unaligned AXI4 Transfers and Their Impact on Data Integrity Unaligned transfers in the AXI4 protocol present unique challenges, particularly when dealing with start addresses that are not aligned with the transfer size. In the scenario described, a 32-bit transfer begins at address 0x01, which is unaligned for a 4-byte transfer. This misalignment affects how data…

ARM Cortex-R52 MPU Configuration Conflict: Device vs. Normal Memory Type Mismatch The ARM Cortex-R52 processor, designed for real-time and safety-critical applications, employs a Memory Protection Unit (MPU) to enforce memory access rules and attributes. One of the critical features of the MPU is its ability to define memory regions with specific attributes, such as Device…

DMB’s Role in Ensuring Relative Order and Cache Maintenance Completion The Data Memory Barrier (DMB) instruction in ARM architectures plays a critical role in ensuring the relative order of memory accesses and cache maintenance operations. However, there is often confusion about whether DMB can also ensure the completion of these operations before subsequent data accesses…

ARM SME Assembly: Challenges with F64 Outer Product Calculations The Scalable Matrix Extension (SME) in ARM architectures introduces powerful capabilities for matrix operations, including outer product calculations. However, implementing floating-point 64-bit (F64) outer products in SME assembly can be challenging due to the complexity of the instruction set, the need for precise memory management, and…

ARM Cortex-A72 and A78 Register Definition Extraction from TRMs The process of extracting register definitions from ARM Cortex-A72 and A78 Technical Reference Manuals (TRMs) presents a significant challenge for engineers tasked with supporting multiple ARM cores. The primary issue revolves around the lack of machine-readable formats for TRMs, which forces developers to resort to parsing…

EL1 Synchronous Exception Handling and Hypervisor Trapping Challenges In the context of ARM Cortex-A53 processors, handling synchronous exceptions at Exception Level 1 (EL1) and routing them to a hypervisor at Exception Level 2 (EL2) presents a complex challenge, particularly when the goal is to implement a health monitoring system for virtual machines (VMs). Synchronous exceptions,…

ARM Cortex-M4 and Helium Fixed-Point Multiplication: Precision and Shift Behavior Fixed-point arithmetic is a cornerstone of digital signal processing (DSP) and embedded systems, particularly when working with microcontrollers like the ARM Cortex-M4 and vector processing extensions like Helium. The core issue revolves around the intrinsic fixed-point multiplication instructions, such as SMULL for the Cortex-M4 and…

Understanding DRAM Bandwidth Measurement on ARM Neoverse-V2 Measuring DRAM bandwidth on ARM-based systems, particularly on high-performance processors like the ARM Neoverse-V2, is a critical task for optimizing workload performance. Unlike Intel processors, where tools like PCM-Memory provide straightforward memory bandwidth measurements, ARM architectures require a more nuanced approach due to differences in hardware performance counters,…

ARMv7 Cortex-A8 Sanitizer Support for Memory Leak and Thread Synchronization Detection The ARMv7 Cortex-A8 processor, a member of the ARM Cortex-A series, is widely used in embedded systems due to its balance of performance and power efficiency. However, like any complex system, software running on the Cortex-A8 can suffer from memory leaks and thread synchronization…

ARM Cortex-M4 DMA Transfer Completion Status and Data Synchronization When dealing with DMA (Direct Memory Access) transfers in ARM Cortex-M4 systems, ensuring proper synchronization between the completion status of the DMA transfer and the subsequent reading of the data buffer is critical. The ARMv8 reference manual, specifically in chapter K14.5.4, discusses the ordering of memory-mapped…