Mercurial > hg > xemacs-beta
diff lisp/cl-extra.el @ 284:558f606b08ae r21-0b40
Import from CVS: tag r21-0b40
author | cvs |
---|---|
date | Mon, 13 Aug 2007 10:34:13 +0200 |
parents | c5d627a313b1 |
children | 57709be46d1b |
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--- a/lisp/cl-extra.el Mon Aug 13 10:33:19 2007 +0200 +++ b/lisp/cl-extra.el Mon Aug 13 10:34:13 2007 +0200 @@ -516,40 +516,45 @@ (defvar float-epsilon) (defvar float-negative-epsilon) +;;(defun cl-float-limits () +(or most-positive-float + (not (featurep 'lisp-float-type)) + (let ((x '2e0) y z) + ;; Find maximum exponent (first two loops are optimizations) + (while (cl-finite-do '* x x) (setq x (* x x))) + (while (cl-finite-do '* x (/ x 2)) (setq x (* x (/ x 2)))) + (while (cl-finite-do '+ x x) (setq x (+ x x))) + (setq z x y (/ x 2)) + ;; Now fill in 1's in the mantissa. + (while (and (cl-finite-do '+ x y) (/= (+ x y) x)) + (setq x (+ x y) y (/ y 2))) + (setq most-positive-float x + most-negative-float (- x)) + ;; Divide down until mantissa starts rounding. + (setq x (/ x z) y (/ 16 z) x (* x y)) + (while (condition-case err (and (= x (* (/ x 2) 2)) (> (/ y 2) 0)) + (arith-error nil)) + (setq x (/ x 2) y (/ y 2))) + (setq least-positive-normalized-float y + least-negative-normalized-float (- y)) + ;; Divide down until value underflows to zero. + (setq x (/ 1 z) y x) + (while (condition-case err (> (/ x 2) 0) (arith-error nil)) + (setq x (/ x 2))) + (setq least-positive-float x + least-negative-float (- x)) + (setq x '1e0) + (while (/= (+ '1e0 x) '1e0) (setq x (/ x 2))) + (setq float-epsilon (* x 2)) + (setq x '1e0) + (while (/= (- '1e0 x) '1e0) (setq x (/ x 2))) + (setq float-negative-epsilon (* x 2)))) +;;) + (defun cl-float-limits () - (or most-positive-float (not (numberp '2e1)) - (let ((x '2e0) y z) - ;; Find maximum exponent (first two loops are optimizations) - (while (cl-finite-do '* x x) (setq x (* x x))) - (while (cl-finite-do '* x (/ x 2)) (setq x (* x (/ x 2)))) - (while (cl-finite-do '+ x x) (setq x (+ x x))) - (setq z x y (/ x 2)) - ;; Now fill in 1's in the mantissa. - (while (and (cl-finite-do '+ x y) (/= (+ x y) x)) - (setq x (+ x y) y (/ y 2))) - (setq most-positive-float x - most-negative-float (- x)) - ;; Divide down until mantissa starts rounding. - (setq x (/ x z) y (/ 16 z) x (* x y)) - (while (condition-case err (and (= x (* (/ x 2) 2)) (> (/ y 2) 0)) - (arith-error nil)) - (setq x (/ x 2) y (/ y 2))) - (setq least-positive-normalized-float y - least-negative-normalized-float (- y)) - ;; Divide down until value underflows to zero. - (setq x (/ 1 z) y x) - (while (condition-case err (> (/ x 2) 0) (arith-error nil)) - (setq x (/ x 2))) - (setq least-positive-float x - least-negative-float (- x)) - (setq x '1e0) - (while (/= (+ '1e0 x) '1e0) (setq x (/ x 2))) - (setq float-epsilon (* x 2)) - (setq x '1e0) - (while (/= (- '1e0 x) '1e0) (setq x (/ x 2))) - (setq float-negative-epsilon (* x 2)))) - nil) - + ;; No-op, defined for old code that calls this to setup the + ;; constants. + ) ;;; Sequence functions.