It is well known that in the field of embedded development, C has long dominated. Although with the development of the times, C++ and assembly language have gradually become more popular, C remains the cornerstone for understanding key concepts such as low-level hardware, memory management, and pointer operations. So, is it necessary to learn C before learning C++?
1. Basics of Hardware InteractionC provides the ability to directly manipulate memory and registers. For example:Using the volatile keyword to define hardware registers prevents compiler optimizations that could lead to control failures.Using pointers to precisely manipulate peripherals like GPIO and timers (e.g., *(volatile uint32_t *)0x40020000 = 0x1 to control an STM32 LED).Significance: Understanding C’s “zero-distance” control over hardware is a prerequisite for later encapsulating the hardware abstraction layer (HAL) in C++ or optimizing critical code with assembly.
2. Memory Management ModelThe malloc/free and stack frame mechanisms in C reveal the essence of memory allocation:Manually managing memory cultivates awareness of resource constraints (e.g., avoiding memory leaks that lead to hardware failures).In contrast to C++’s new/delete and smart pointers (like unique_ptr), one must first understand the underlying logic before using higher-level abstractions.
3. Pointers and Address ArithmeticPointers are the core of C and the foundational implementation of C++ features like references and iterators:Using pointers to traverse an array of sensor data (e.g., int16_t *data = (int16_t *)0x20001000) helps understand memory layout.Mastering pointer arithmetic paves the way for C++ polymorphism (virtual function table pointers) and memory alignment optimizations.
4. Connection to Compilation PrinciplesThe compilation process of C code (preprocessing → assembly → linking) directly corresponds to assembly language:Using gcc -S to generate assembly code allows observation of how C statements map to mov/jmp instructions.Understanding calling conventions (e.g., ARM’s R0-R3 for parameter passing) lays the foundation for mixed programming (inline assembly).
5. System-Level CompatibilityOver 80% of existing embedded system codebases are in C (e.g., Linux kernel, FreeRTOS):When modifying low-level drivers or porting systems, knowledge of C can quickly locate issues (e.g., bare-metal programming of interrupt service routines (ISRs)).Avoid compatibility risks of C++ features like exception handling and RTTI in resource-constrained environments.
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