Messages in this thread | | | Date | Sat, 17 Dec 2005 21:44:02 +0000 | From | Russell King <> | Subject | Re: [PATCH 1/12]: MUTEX: Implement mutexes |
| |
On Sat, Dec 17, 2005 at 12:11:39PM -0800, Linus Torvalds wrote: > Of the other architectures you list, only ARM is really important. And no, > arm doesn't do swap. It does LL/SC (except they call it "ldrex/strex", > which I assume stands for "load/store with reservation and X just because > X is cool. Yeah, we're cool" (*)).
> (*) Actually, some arm docs I found implies that "ex" stands for > "exclusive", but that leaves me wondering what the "r" stands for?
FYI. The standard instructions:
ldr = load register str = store register
The new (ARM architecture v6 and above) atomic instructions:
ldrex = load register exclusive strex = store register exclusive
Previous architecture versions only have the 32-bit and 8 bit unconditional swap instructions. Luckily they're unlikely to be used for SMP in the field.
-- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |