Messages in this thread | | | Subject | Re: [Patch] performance enhancement for simple_strtoul | Date | Thu, 21 Dec 2000 16:07:33 +0000 (GMT) | From | Alan Cox <> |
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> On Wed, 20 Dec 2000, Steve Grubb wrote: > > > + while (isdigit(c)) { > > + result = (result*10) + (c & 0x0f); > > + c = *(++cp); > > + } > > x * 10 can be written as: > > (x << 2 + x) << 1 = (4x+x) * 2 > (x << 3) + (x << 1) = 8x + 2x
Since when has printk been performance critical. It isnt worth microoptimising (or in your case for some cpus micropessimising) that stuff. Besides, gcc should work it out if its worth doing
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