Late at night, a newly promoted technical manager murmurs to himself at his workstation: “This requirement is clearly logically perfect, the schedule is precise to the millisecond, why are there more bugs than code when it comes to execution?” The cleaning lady next door passes by and softly comments: “Young man, a team is not … Read more
As the Internet of Things market matures, Bluetooth technology, as one of the mainstream wireless connection technologies that supports the “Internet of Everything,” is also accelerating its evolution, bringing greater application space. Speaking of Bluetooth, we often use devices related to Bluetooth functionality in our lives. Although they are all Bluetooth, there are many differences, … Read more
Eight Different Emotions Corresponding Body Language and Facial Expressions Emotion Corresponding Body Language and Facial Expressions Happy delighted /excited burst into laughter, clap one’s hands, eyes twinkle, grin from ear to ear; wear a broad smile, jump up and cheer; eyes shining with wild joy and lips curving into a smile Disappointed upset /disappointed lower … Read more
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Wi-Fi (pronounced: /ˈwaɪfaɪ/) is also known in Chinese as “Mobile Hotspot”. It is a trademark of the Wi-Fi Alliance manufacturers as a brand certification for products, and is a wireless local area network technology based on the IEEE 802.11 standard. The term Wi-Fi is commonly misunderstood to mean Wireless Fidelity, and even the Wi-Fi Alliance … Read more
Background Read the fucking source code! –By Lu Xun A picture is worth a thousand words. –By Gorky Note: Kernel Version: 4.14 ARM64 Processor, Cortex-A53, Dual-core Tools Used: Source Insight 3.5, Visio 1. Introduction To understand Linux page table mapping well, it is necessary to be familiar with the MMU mechanism, so these two modules … Read more
Continuing from the previous article on ARMV8-A MMU – Part 1. IPS[34:32] (Intermediate Physical Address Size) controls the size of the IPA address space. When IPS=000, it indicates a 32-bit address space; when IPS=101, it indicates a 48-bit address space. The meanings of other values can be referenced in the ARMv8 documentation. After setting the … Read more
Continuing from the previous article on Introduction to MMU in ARMV8-A – Part 2. This article will continue from the last section and explain the multi-level page tables of MMU. The previous section discussed an example of a single-level page table, while this section will discuss an example of a two-level page table. Below is … Read more
1. Concept of Address Translation The code in ARMV8-A generally uses virtual addresses for addressing access, which are converted into physical addresses in the memory system. This conversion is performed by a component of the processor called the MMU. The MMU uses a translation table to convert virtual addresses to physical addresses; this translation table … Read more
Continuing from the previous article, Introduction to MMU in ARMV8-A – Part 4. Page Tables in ARMV8-A ARMV8-A supports three types of page table formats: ARMV8-A AArch64 Long Descriptor Format ARMV7-A Long Descriptor Format, such as the Large Physical Address Extension (LPAE) in the ARM Cortex-A15 processor ARMV7-A Short Descriptor Format Although ARMV8-A uses the … Read more