如何解决Valayle Qualisher任何访问都是原子的？

嗨，我有这个函数：但是地址位于cpu寄存器r04，变量操作（地址|=0b10000000）是不可能的。我试图定义这个函数，如（void）lcd_set_cursor_at_address（易失性无符号字符地址），但是地址总是位于r04 cpu寄存器mplabXC32com中。皮勒用户指南81.2表示：…Valayle Qualisher并不保证任何访问都是原子的，但是编译器会尝试实现这一点。……我该如何解决这个问题？pic是pic32mx440f256hxc32 v1.42，在windows 10（在项目属性中）优化级别是0pre-optimization指令调度=default for optimization levelpost-optimization指令调度=default for optimization级别



      以下为原文

    Hi,
I have this function :
(void) lcd_set_cursor_at_address (unsigned char address)
{
address |= 0b10000000; //most significant bit must be 1 for lcd command
lcd_command(address);
}


but address is located at cpu register r04 and variable manipulation (address |= 0b10000000) is not possible.

I tried to define this function like
(void) lcd_set_cursor_at_address ( volatile unsigned char address)
but address is always located  in r04 cpu register

mplab XC32 compiler user guide 8.10.2 says:
..... The VOLATYLE qualyfier does not guarantee tha any access will be atomic, but the compiler will try to implement this.  .....
How do i solve this issue?

pic is pic32mx440f256h
xc32 v1.42 on windows 10
(in project properties)
optimization-level  is 0
pre-optimization instruction scheduling = default for optimization level
post-optimization instruction scheduling = default for optimization level