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-infinity and REPRESENT
From: |
Anton Ertl |
Subject: |
-infinity and REPRESENT |
Date: |
Mon, 4 May 2020 17:24:07 +0200 |
User-agent: |
NeoMutt/20170113 (1.7.2) |
I just re-implemented REPRESENT.
One issue is how to deal with -infinity (e.g., the result of -1e 0e f/).
Previously Gforth 0.7.2+glibc produced "-inf" and f1=0 (positive),
f2=0 (not valid); other libc implementations might lead to different
results.
gforth 0.7.9_20200423 uses an ecvt_r supplied by us and produces
"-inf" and f1=-1 (negative), f2=0 (not valid); the new REPRESENT
currently works in the same way (except that it gives you "-infinity",
space permitting).
In both systems F. and FS. outputs -in.
iForth behaves like gforth 0.7.2.
VFX produces "Inf" and f1=-1, f2=0.
The VFX behaviour looks like the most sensible one to me, but it might
affect code that uses REPRESENT; we can change our own code
accordingly, but what about your code? Do you have code that uses
REPRESENT and that has been designed for a specific behaviour when
getting -infinity?
- anton
- -infinity and REPRESENT,
Anton Ertl <=