notes

C++ 编写的EROS RTOS

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I have adopted some conventions in the kernel code, primarily out of
self-defense. This is an attempt to list them so that other people
deciding to work on the kernel will not stumble over some of the
things that I have:

NO BITFIELDS

The current kernel uses bitfields very sparingly, and in most places I
would prefer to entirely remove them.  While bitfield
insertion/extraction seems to work okay, I have found bitfield logical
operations to be unreliable.  My personal favorite was a piece of code
that read:

	if (pOb->flags.dirty == 0) {
	   ...
	   printf(" .... dirty: %c ... \n", pObj->flags.dirty ? 'y' : 'n');
	   ...
        }

Sure enough the dman thing printed 'y'.

More broadly, bitfields are a sufficiently underused feature that they
tend to be badly tested and poorly optimized.