* bug#17556: 24.4.50; fix math-bignum
@ 2014-05-23 4:46 Leo Liu
2014-05-23 7:33 ` Andreas Schwab
2014-05-24 15:19 ` Leo Liu
0 siblings, 2 replies; 5+ messages in thread
From: Leo Liu @ 2014-05-23 4:46 UTC (permalink / raw
To: 17556
Due to integer overflow (math-bignum most-negative-fixnum) is incorrect.
Any objection if I fix it like in this patch:
=== modified file 'lisp/calc/calc.el'
--- lisp/calc/calc.el 2014-01-01 07:43:34 +0000
+++ lisp/calc/calc.el 2014-05-23 04:42:18 +0000
@@ -2773,9 +2773,15 @@
;; Coerce integer A to be a bignum. [B S]
(defun math-bignum (a)
- (if (>= a 0)
- (cons 'bigpos (math-bignum-big a))
- (cons 'bigneg (math-bignum-big (- a)))))
+ (cond
+ ((>= a 0)
+ (cons 'bigpos (math-bignum-big a)))
+ ((= a most-negative-fixnum)
+ ;; Note: (- most-negative-fixnum) is most-negative-fixnum
+ (math-sub (cons 'bigneg (math-bignum-big (- (1+ a))))
+ 1))
+ (t
+ (cons 'bigneg (math-bignum-big (- a))))))
(defun math-bignum-big (a) ; [L s]
(if (= a 0)
^ permalink raw reply [flat|nested] 5+ messages in thread
* bug#17556: 24.4.50; fix math-bignum
2014-05-23 4:46 bug#17556: 24.4.50; fix math-bignum Leo Liu
@ 2014-05-23 7:33 ` Andreas Schwab
2014-05-23 8:23 ` martin rudalics
2014-05-23 9:44 ` Leo Liu
2014-05-24 15:19 ` Leo Liu
1 sibling, 2 replies; 5+ messages in thread
From: Andreas Schwab @ 2014-05-23 7:33 UTC (permalink / raw
To: Leo Liu; +Cc: 17556
Leo Liu <sdl.web@gmail.com> writes:
> + (math-sub (cons 'bigneg (math-bignum-big (- (1+ a))))
aka (- 1 a)
Andreas.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."
^ permalink raw reply [flat|nested] 5+ messages in thread
* bug#17556: 24.4.50; fix math-bignum
2014-05-23 7:33 ` Andreas Schwab
@ 2014-05-23 8:23 ` martin rudalics
2014-05-23 9:44 ` Leo Liu
1 sibling, 0 replies; 5+ messages in thread
From: martin rudalics @ 2014-05-23 8:23 UTC (permalink / raw
To: Andreas Schwab, Leo Liu; +Cc: 17556
>> + (math-sub (cons 'bigneg (math-bignum-big (- (1+ a))))
>
> aka (- 1 a)
Hmmm...
martin
^ permalink raw reply [flat|nested] 5+ messages in thread
* bug#17556: 24.4.50; fix math-bignum
2014-05-23 7:33 ` Andreas Schwab
2014-05-23 8:23 ` martin rudalics
@ 2014-05-23 9:44 ` Leo Liu
1 sibling, 0 replies; 5+ messages in thread
From: Leo Liu @ 2014-05-23 9:44 UTC (permalink / raw
To: Andreas Schwab; +Cc: 17556
On 2014-05-23 09:33 +0200, Andreas Schwab wrote:
> aka (- 1 a)
aka most-positive-fixnum ;)
Leo
^ permalink raw reply [flat|nested] 5+ messages in thread
* bug#17556: 24.4.50; fix math-bignum
2014-05-23 4:46 bug#17556: 24.4.50; fix math-bignum Leo Liu
2014-05-23 7:33 ` Andreas Schwab
@ 2014-05-24 15:19 ` Leo Liu
1 sibling, 0 replies; 5+ messages in thread
From: Leo Liu @ 2014-05-24 15:19 UTC (permalink / raw
To: 17556-done
Fixed in 24.5
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2014-05-24 15:19 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2014-05-23 4:46 bug#17556: 24.4.50; fix math-bignum Leo Liu
2014-05-23 7:33 ` Andreas Schwab
2014-05-23 8:23 ` martin rudalics
2014-05-23 9:44 ` Leo Liu
2014-05-24 15:19 ` Leo Liu
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