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-rw-r--r--lisp/emacs-lisp/cl-extra.el5
1 files changed, 2 insertions, 3 deletions
diff --git a/lisp/emacs-lisp/cl-extra.el b/lisp/emacs-lisp/cl-extra.el
index 90533295b68..ca33c56a958 100644
--- a/lisp/emacs-lisp/cl-extra.el
+++ b/lisp/emacs-lisp/cl-extra.el
@@ -332,10 +332,9 @@ If so, return the true (non-nil) value returned by PREDICATE.
;;;###autoload
(defun cl-isqrt (x)
- "Return the integer square root of the argument."
+ "Return the integer square root of the (integer) argument."
(if (and (integerp x) (> x 0))
- (let ((g (cond ((<= x 100) 10) ((<= x 10000) 100)
- ((<= x 1000000) 1000) (t x)))
+ (let ((g (ash 2 (/ (logb x) 2)))
g2)
(while (< (setq g2 (/ (+ g (/ x g)) 2)) g)
(setq g g2))