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Re: Immediate doubles (up to 2^256) and rationals coming to Guile 3
From: |
Mark H Weaver |
Subject: |
Re: Immediate doubles (up to 2^256) and rationals coming to Guile 3 |
Date: |
Tue, 11 Jun 2019 07:34:08 -0400 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) |
Ludovic Courtès <address@hidden> writes:
> Though an immediate, like a fixnum or an iflo, is still something
> different from a tagged heap object like a pair, right?
I should clarify that in this new approach, a pair is *not* a tagged
heap object. Tagged heap objects are those which have a tag in their
first word. In this new approach, pairs are not tagged in this sense,
and it is no longer possible to distinguish a pair from a non-pair by
looking at their raw heap blocks.
Tagged heap objects (thobs) have 000 in the low 3 bits of the SCM.
Pairs have 0110 in the low 4 bits of the SCM.
Regards,
Mark
- Re: Immediate doubles (up to 2^256) and rationals coming to Guile 3, (continued)
Re: Immediate doubles (up to 2^256) and rationals coming to Guile 3, Mark H Weaver, 2019/06/07