Messages in this thread | | | Date | Wed, 15 Aug 2007 23:37:21 -0400 | From | Bill Fink <> | Subject | Re: [PATCH 0/24] make atomic_read() behave consistently across all architectures |
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On Wed, 15 Aug 2007, Satyam Sharma wrote:
> (C) > $ cat tp3.c > int a; > > void func(void) > { > *(volatile int *)&a = 10; > *(volatile int *)&a = 20; > } > $ gcc -Os -S tp3.c > $ cat tp3.s > ... > movl $10, a > movl $20, a > ...
I'm curious about one minor tangential point. Why, instead of:
b = *(volatile int *)&a;
why can't this just be expressed as:
b = (volatile int)a;
Isn't it the contents of a that's volatile, i.e. it's value can change invisibly to the compiler, and that's why you want to force a read from memory? Why do you need the "*(volatile int *)&" construct?
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