To sum up, it is to tell the compiler that pao3 is an address value rather than an integer variable value, although their expressions are the same! Then analyze the above C language in detail. " u32 *pao3 "

The variable type is not u32, but u32*. It means that the address where the variable name pao3 is located is an address value. If it is u32, it means that only a 32-bit plastic data is stored. The address 0x4ffff000 1 stores 32-bit plastic data, which can be the value of a plastic variable or a 32-bit register. The (u32*) after the assignment statement is a cast. The assignment must be consistent with the defined variable. You can also try changing that sentence to U32 * Pao3 = (U32) (0x4fff0001) or u32 *pao3=0x4FFF000 1+0, and an error will occur. The compiler thinks that you assigned an integer variable to a pointer variable. So if you want to take the value of this register (0x4FFF000 1), take *pao, such as printf("%x\n ",*pao). If you are in a computer, you will get the display of13247a1a.