![how to use rom variable in keil mdk arm how to use rom variable in keil mdk arm](https://us.v-cdn.net/6029336/uploads/editor/2q/jpc1crd7fdj2.png)
When you get toward the end of a project you will need to select the “create hex file” option to generate a HEX32 file which can be used with a production programmer. The default is to create a standalone project with debug information. Here, we can choose between generating a standalone program by selecting “Create Executable” or we can create a library which can be added to another project. The output menu allows you to control the final image of your project ( Fig. The six major sections of program memory correspond to executable code, statically allocated variables, dynamically allocated variables, and automatically allocated variables. The address of a dynamic variable is always stored in another variable, known as a pointer, which may be an automatic or static variable, or even another dynamic variable. Dynamic variables are allocated from the heap, using, , or a language-dependent equivalent. The address of an automatic variable is always computed as an offset from the stack pointer. The stack pointer is adjusted down to make space for the newly allocated variable. Automatically allocated variables, often referred to as local variables, are stored on the stack. The address of a statically allocated variable is fixed at the time the program begins running, and cannot be changed. The storage space is reserved, and usually initialized, when the program is loaded and begins execution. Statically allocated variables are allocated in the, , or section. In a high level language, storage space for a variable can be allocated in one of three ways: statically, dynamically, and automatically. Typical memory layout for a program with a 32-bit address space. Golden Rule 3: The size of a structure cannot depend on its context.įigure 1.7. Adding padding or trailing bytes only when simple is used as a component of a structure or of an array would make its size ambiguous. It is worth noting that the size of operator must always yield the same value when applied to a type. Removing any of the padding or trailing bytes would make B improperly aligned in some cases (try to lay out vect if simple has no trailing bytes). In all cases, B retains an offset that is a multiple of 2.
How to use rom variable in keil mdk arm code#
For BUS16, the same code fragment would yield a natural boundary of 2 and a size of 8 for simple.
![how to use rom variable in keil mdk arm how to use rom variable in keil mdk arm](https://img2018.cnblogs.com/i-beta/1360760/201912/1360760-20191201075040317-1981746049.png)
In all instances of structure simple, B retains an offset that is a multiple of 4. By following the Golden Rules, the compiler guarantees that B is properly aligned in every possible case, as shown by the memory layouts for structure simple, array vect, and structure outer. The most demanding member in simple is the integer B, whose natural boundary is 4 on BUS32. On BUS32, the natural boundary for simple is 4, which means its size must be 12. For example, AAAA represents a 4-byte structure member.Ĭurly braces surround an unpacked structure. The letter is repeated to show how many bytes the member occupies (one letter per byte). Uppercase letters denote a nonbit structure member.