ARM Cortex-R4/R5 PC Value Offset During Execution The Program Counter (PC) in ARM Cortex-R4 and Cortex-R5 processors exhibits a behavior where it points 8 bytes ahead of the current instruction being executed. This offset is not a bug or an anomaly but a deliberate architectural design choice rooted in the history of ARM processors and…
Cortex-M55 Default Address Map and Boot Vector Placement The Cortex-M55 processor, like other ARM Cortex-M series processors, follows a predefined memory map that dictates how the processor interacts with memory and peripherals. This memory map is crucial for understanding where code, data, and peripherals are located, and it plays a significant role in the boot…
Variable Execution Time of UDIV Due to Early Termination Mechanism The ARM Cortex-M4 processor, like many modern microcontrollers, incorporates a hardware division unit that supports both signed (SDIV) and unsigned (UDIV) integer division. While this feature significantly accelerates division operations compared to software-based implementations, it introduces a critical challenge for developers requiring deterministic execution times….
ARM MMU-600 TBU and TCU Invalidation Message Scenarios The ARM MMU-600 (Memory Management Unit) is a critical component in modern ARM-based systems, particularly in high-performance computing and embedded systems where memory management and translation are paramount. The MMU-600 consists of two primary units: the Translation Buffer Unit (TBU) and the Translation Control Unit (TCU). Understanding…
ARMv8-A72 MMU Translation Error at Level 1 During Initialization When enabling the Memory Management Unit (MMU) on an ARMv8-A72 processor, a common issue that arises is a translation error at Level 1 of the page table hierarchy. This error typically occurs immediately after setting the MMU enable bit in the System Control Register (SCTLR_EL3). The…
ARM Pseudocode Arithmetic: Bitstring and Integer Operations in PC Relative Addressing The ARM architecture employs pseudocode to describe the behavior of instructions and operations in a human-readable yet precise manner. One such operation involves the subtraction of an integer from a bitstring, specifically in the context of Program Counter (PC) relative addressing. This operation is…
ARM Cortex-A78 DC ZVA Instruction Alignment Fault During Linux Kernel Boot DC ZVA Instruction Execution Failure in __pi_memset Function The ARM Cortex-A78 processor is encountering an alignment fault when executing the DC ZVA (Data Cache Zero by VA) instruction within the __pi_memset function during the Linux kernel boot process. The __pi_memset function is part of…
Cortex-R8 SMP Core 0 Stuck in WFE State After SEV Execution In a multi-core Cortex-R8 system, Core 0 enters a Wait For Event (WFE) state while waiting for a spinlock. Despite another core executing a Send Event (SEV) instruction, Core 0 fails to wake up and resume execution. This behavior indicates a breakdown in the…
ARM Cortex-M33 IBUSERR Flag Generation and HardFault/BusFault Scenarios The IBUSERR flag, represented by bit 0 in the BusFault Status Register (BFSR), is a critical indicator of instruction bus errors on ARM Cortex-M33 processors. When the IBUSERR flag is set, it signifies that the processor has encountered a fault during an instruction fetch operation. This fault…
GIC-600 ACE-Lite Slave Port and Its Role in Register Access The Generic Interrupt Controller 600 (GIC-600) is a critical component in ARM-based systems, responsible for managing interrupts across multiple processors and peripherals. One of the key architectural features of the GIC-600 is its ACE-Lite slave port, which is used for accessing its internal registers. The…