[C/C++] Register值修改

直接看範例:

Example 1:
*((volatile unsigned char *) 0x1e) = 0x16;
這句等義於:
volatile unsigned char *ptr = 0x1e;
*ptr = 0x16;

Example 2:
char reg8 = *((volatile unsigned char *) 0x1e);
reg8 = reg8 | (1<<7);
*((volatile unsigned char *) 0x1e) = reg8;
等義於:
unsigned char reg8 = *((volatile unsigned char *) 0x1e);
reg8 = reg8 | (1<<7);
volatile unsigned char *ptr = 0x1e;
*ptr = reg8;

參考文章: https://blog.csdn.net/wear_/article/details/52129421