Messages in this thread | | | Date | Mon, 17 Mar 2003 12:49:20 -0500 | From | Jeff Garzik <> | Subject | Re: sundance DFE-580TX DL10050B patch |
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On Mon, Mar 17, 2003 at 06:40:36PM +0100, Philippe De Muyter wrote: > Dave Jones wrote : > > On Mon, Mar 17, 2003 at 02:56:09PM +0100, Philippe De Muyter wrote: > > > > > + writew((dev->dev_addr[i + 1] << 8) + dev->dev_addr[i], > > > > Don't you want to OR those together instead of add them ? > > > > Dave > > > You're right.
No.
Adding and or'ing are exactly equivalent for the above case, where you shift an 8-bit value left 8 bits, then add it to another 8-bit value.
The final answer may be obtained from examining the compiler's assembly output, and see which combination ('or' or 'add') produces the best code.
Jeff
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