armcc 是否使用 -O0 优化非易失性变量？
int* Register = 0x00FF0000; // Address of micro-seconds timer
while(*Register != 0);
在使用armcc编译器和-O0优化时，我应该将*Register声明为易失性吗？
换句话说： -O0 优化是否需要将此类变量限定为 易失性 ？ （这可能是 -O2 优化所需要的）
int* Register = 0x00FF0000; // Address of micro-seconds timer
while(*Register != 0);
Should I declare *Register as volatile while using armcc compiler and -O0 optimization ?
In other words: Does -O0 optimization requires qualifying that sort of variables as volatile ? (which is probably required in -O2 optimization)
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在我看来，无论如何，你都应该将
Register声明为易失性，因为它是易失性的。将其标记为易失性并没有什么坏处，因为您依赖于编译器不会优化通过指针的访问。您不应该依赖编译器优化设置来希望它能够正确编译。我猜想，忘记适当地标记事物
易失性是对嵌入式 C 代码进行优化通常会导致事物开始崩溃的主要原因。It seems to me that you should declare
Registerasvolatileregardless, since it is volatile. There's no harm in marking itvolatile, since you're depending on the compiler not optimizing away the accesses through the pointer.You shouldn't depend on the compiler optimization settings to hope this gets compiled correctly. I'd guess that forgetting to mark things
volatileappropriately is a major reason that cranking up optimizations on embedded C code often causes things to start breaking.