ARM Processor Programming Modes - ARM Processor - Microcontroller and Embedded Programming | Summary and Q&A

TL;DR

This video discusses the different modes of the ARM processor, including privileged and non-privileged modes, and how they affect register availability and access to the current program status register.

Key Insights

• ®️ The ARM processor has different modes that determine register availability and access to the current program status register.
• 🫠 Privileged modes provide full read and write access to the CPSR, while non-privileged modes only allow read access to the control field.
• 📳 User mode is a non-privileged mode where most tasks are executed, while supervisor mode provides additional privileges and control over the system.
• 🍵 Fast interrupt request mode handles high-priority interrupts, while interrupt mode handles low-priority interrupts.
• 🍵 Abort mode is used for handling failed memory access attempts, and undefined mode handles undefined instructions.

Transcript

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Questions & Answers

Q: What is the purpose of the different modes in the ARM processor?

The different modes determine register availability and access to the current program status register, allowing programmers to control and manipulate the processor based on their specific requirements.

Q: What is the difference between privileged and non-privileged modes?

In privileged modes, programmers have full read and write access to the current program status register (CPSR), while in non-privileged modes, only read access to the control field in CPSR is provided.

Q: What is the user mode and what tasks are executed in this mode?

User mode is a non-privileged mode where most tasks of the ARM processor are executed. However, access to memory and direct reading of hardware devices is restricted in this mode.

Q: When is the fast interrupt request mode (FIQ) used?

The fast interrupt request mode is a privileged mode used to handle high-priority interrupts generated by peripherals, such as floppy disks. It allows programmers to read and write the CPSR.

Summary & Key Takeaways

• The ARM processor is programmable and can be used in embedded systems due to its small size.

• Different modes of operation of the processor determine register availability and access to the current program status register.

• There are seven operating modes, categorized into privileged and non-privileged modes.