Recently, while writing a small tool in C, I needed to obtain the offset of structure member variables within the entire structure. The first method that came to mind was to directly calculate the difference based on pointer characteristics. However, I discovered a second method using a standard C operator to obtain the offset, similar … Read more
@[toc] Impact and Efficiency Trade-offs of DMA Memory Address Alignment in ARM Cortex-M Cores Insert image description here 1. Introduction In embedded systems based on high-performance microcontrollers such as ARM Cortex-M4/M7, Direct Memory Access (DMA) is a key technology for achieving high data throughput and reducing CPU load. However, the efficient operation of the DMA … Read more
PS: Please indicate the source when reprinting, all rights reserved by the author.PS: This is just based on my own understanding,if it conflicts with your principles and ideas, please forgive me, do not criticize. Environment Description None Introduction Preface: I am a lazy person, bored and idle. While browsing the internet, I accidentally discovered something … Read more
There is also a “C Language Knowledge Architecture Diagram” Download link for the dual high-definition images: http://down.51cto.com/data/2239071 Memory Alignment: http://11142019.blog.51cto.com/11132019/1846832 Diamond Inheritance: http://11142019.blog.51cto.com/11132019/1846836 C++ Object Model & Virtual Function Table: http://11142019.blog.51cto.com/11132019/1846838 Deep Copy and Shallow Copy: http://11142019.blog.51cto.com/11132019/1846840 String Implementation: http://11142019.blog.51cto.com/11132019/1846841 Copy on Write: http://11142019.blog.51cto.com/11132019/1846842 New/Delete and New[]/Delete[]: http://11142019.blog.51cto.com/11132019/1846844 Smart Pointers: http://11142019.blog.51cto.com/11132019/1846846 Circular References & Custom … Read more
This article is authored by: Wang Fanghao, edited by: Apollo. The following article is provided by Community Evangelist – Wang Fanghao, and it mainly introduces C++ Memory Alignment. About the Author Wang Fanghao, a community evangelist, graduated from Wuhan University with a degree in Electronic Information. He has worked at Huawei and Alibaba on firmware, … Read more
Scan the code to follow Chip Dynamics , and say goodbye to “chip” congestion! Search WeChatChip Dynamics When defining a structure while coding, you might find that it occupies more memory than the sum of its members’ sizes. For example, a struct { char a; int b; } has a char that occupies 1 byte … Read more
① The Compilation Process of C Language.c files are transformed into executable files through four stages: preprocessing, compilation, assembly, and linking.(1) Preprocessing: Includes header file inclusion, macro replacement, conditional compilation, and comment removal.(2) Compilation: The C language is translated into assembly, outputting a .s assembly file;(3) Assembly: The assembly file is translated into binary, outputting … Read more
1. The Concept of “Memory Alignment” Memory alignment, also known as byte alignment, is an attribute of the memory address where a data type can be stored. This attribute is essentially the memory address itself, which must conform to certain specifications. This specification states that the memory address value must be a power of 2. … Read more
Today, I bring you a classic and commonly mistaken question about memory alignment of C language structures: Calculate the number of bytes occupied by the following structure in a 32-bit environment: typedef struct test_struct { char a; short b; char c; int d; char e; }test_struct; Please provide your answer: Let’s take a look at … Read more