Messages in this thread | | | Date | Sun, 27 Mar 2005 17:12:07 -0500 (EST) | From | linux-os <> | Subject | Re: [PATCH] no need to check for NULL before calling kfree() -fs/ext2/ |
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On Sat, 26 Mar 2005, Marcin Dalecki wrote:
> > On 2005-03-27, at 00:21, linux-os wrote: >> >> Always, always, a call will be more expensive than a branch >> on condition. It's impossible to be otherwise. A call requires >> that the return address be written to memory (the stack), >> using register indirection (the stack-pointer). >> > Needless to say that there are enough architectures out there, which > don't even > have something like an explicit call as separate assembler > instruction... >
Yes, they break the 'call' into seperate expensive operations like loading the IP address that will exist after the call into a register storing that in a dedicated register, used as a "stack", then branching to the called procedure with another indirection, etc.
>
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