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Re: [Emacs-diffs] /srv/bzr/emacs/trunk r107377: * src/lisp.h: Improve co
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From: |
Paul Eggert |
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Subject: |
Re: [Emacs-diffs] /srv/bzr/emacs/trunk r107377: * src/lisp.h: Improve comment about USE_LSB_TAG. |
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Date: |
Wed, 22 Feb 2012 22:28:28 -0800 |
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User-agent: |
Mozilla/5.0 (X11; Linux i686; rv:10.0.2) Gecko/20120216 Thunderbird/10.0.2 |
On 02/22/2012 07:57 PM, YAMAMOTO Mitsuharu wrote:
> Does "untagging by subtraction instead of masking" improve the
> performance of USE_LSB_TAG in your platform?
I'm sure it would, though I haven't measured it.
I'm surprised that this hasn't been implemented in Emacs already.
It's a standard technique (I first saw it in the 1980s), and it's clearly
faster that what Emacs is doing now. We should look into incorporating it
after 24.1 comes out.