[Vm-dev] Interpreter>>isContextHeader: optimization
siguctua at gmail.com
Mon Feb 23 07:01:54 UTC 2009
2009/2/23 Yoshiki Ohshima <yoshiki at vpri.org>:
> At Sat, 21 Feb 2009 09:37:29 +0200,
> Igor Stasenko wrote:
>> i think it wouldn't hurt to rewrite it as:
>> isContextHeader: aHeader
>> self inline: true.
>> | hdr |
>> hdr := aHeader bitAnd: (16r1F << 12).
>> ^ hdr = (13 << 12) "MethodContext"
>> or: [ hdr = (14 << 12) "BlockContext"
>> or: [ hdr = (4 << 12)]] "PseudoContext"
> This is totally tangent but I was supposed to relay a message from
> somebody (IIRC it was originally from Dave Ungar but a few hops in
> between) pointed out that "13" is BlockContext and "14" is
> MethodContext in the image.
I just copied the source, didn't really changed anything in it.. so it
sits there for a while :)
> (This level of nitpicking may not have anything to do with average
> Squeakers but for VM hackers I understand it could be crucial^^;)
Yup, this is another argument in having:
^ self isMethodContext or: [self isBlockContext or: [self isPseudoContext ]]
instead of numerous #bitAnd: and #<< in many different places :)
> -- Yoshiki
Igor Stasenko AKA sig.
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