> The following functions or macros will be exported by <machine/lock.h>:
> 
> 	void cpu_simple_lock_init(__volatile struct simplelock *alp);
> 	void cpu_simple_lock(__volatile struct simplelock *alp);
			while (alp->lock_data != 0) /* spin */;
			alp->lock_data = 1;

> 	int cpu_simple_lock_try(__volatile struct simplelock *alp);
> 	void cpu_simple_unlock(__volatile struct simplelock *alp);
...

> 			alp->lock_data = 0;

Is the intent here that lock_data always be "1" for locked and "0" for
unlocked?  Is it intended to be OK for code to examine lock_data
directly?  or should only cpu_simple_lock_try be used for that?

On one architecture I'm aware of, it's more convenient for "0" to mean
locked and "1" to mean unlocked (PA-RISC, which does have MP systems;
also, some people have expressed interest in a port to the PA in the
past).
						- Bill