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SIGNUM in integer form
- To: Guy.Steele@CMU-CS-A.ARPA
- Subject: SIGNUM in integer form
- From: Bill Gosper <rwg@NIMBUS.SPA.Symbolics>
- Date: Thu, 25 Oct 84 23:47 PDT
- Cc: common-lisp@SU-AI.ARPA
- In-reply-to: The message of 21 Oct 84 21:47-PDT from Guy.Steele@CMU-CS-A.ARPANET
Date: 22 Oct 84 0047 EDT (Monday)
Maybe what you want is the third value from INTEGER-DECODE-FLOAT?
(Not the most elegant thing, I admit.)
No, for 1.5 reasons:
1) It doesn't return 0 for 0.
1.5) It isn't documented what happens for integer arg.
Semi-apropos those pages, I really wish there were SCALE-BY-POWER-OF-2,
which various implementations could do much faster than
multiplication, for almost any representation of any kind of number.
SCALE-FLOAT can't do this because of hexadecimal affirmative action,
and having the wrong name.