Multitasking operating system is a software that offers interleave execution of more than one process. It is capable of executing several processes concurrently and therefore giving an illusion of parallelism in the view of user abstraction. Multitasking operating systems come in two flavors: cooperative multitasking and preemptive multitasking. In Read more…
It is about two more weeks before my internship at Aeste ends. Yesterday, I finished my task of cleaning up LLVM floating points instructions and cache instructions. What I did was just hunt all these unwanted instructions inside AEMB target Read more…
My recent task is to clean up the instructions from LLVM code. One must wonder why do I need to clean up the instructions, well perhaps the definition of my recent task was not adequately explain here. AEMB is considered Read more…
Just read another interesting piece on why it is becoming increasingly more beneficial for people to join startups instead of large corporations. Quoting the main bits of the article: The Steady Income Myth In an adequately funded startup company one Read more…
AEMB is a family of highly-rated open-source embedded microprocessor core. All the programs for AEMB have to run in a simulation environment, because the core has not yet been implemented in silicone chip. Recently, one of the interns is assigned with Read more…
Having the understanding of HZ, jiffies, and system timer, it is appropriate to discuss the implementation of time management. Most of the jobs in time management are handled by a dedicated function called timer handler. In Microblaze, the kernel registers timer_interrupt as the Read more…
Time management is crucial to Linux kernel. A massive of kernel functions are time-driven and therefore it is heavily dependent on time management. In Linux kernel, time management is handled by a piece of programmable hardware, known as system timer. Read more…
In LLVM system compiler, there is an option in the command command -mattr called target specific attributes. You may check each target attributes by using this command. llvm-as < /dev/null || llc -march=aemb -mattr=help note that -march=aemb is to select Read more…
Having the discussion of tick rate in my previous post, it is therefore appropriate to introduce jiffies in linux kernel. Jiffies is a global variable declared in <linux/jiffies.h> as: extern unsigned long volatile jiffies; Its only usage is to store the Read more…
For the past few weeks, I was given a task by my supervisor. The task sound simple, whenever there NOP (No operation) instruction will be use, LLVM should change it into XOR R0, R0, R0 which basically doing nothing since Read more…