Move from github, collapse gltk and strictmath, add candle

[clnl] / resources / strictmath / otherconversions / gen-float64-sign.lisp

diff --git a/resources/strictmath/otherconversions/gen-float64-sign.lisp b/resources/strictmath/otherconversions/gen-float64-sign.lisp
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+;;;; -*- Mode: Lisp; Syntax: Common-Lisp; Package: System; Base: 10 -*-
+;;;;
+;;;; evcl - 12 - Number - float64-sign
+;;; arch/generic/lisp/math/gen-math-f32-sign.lisp
+;;;
+;;; This file is part of Evita Common Lisp.
+;;;
+;;; Copyright (C) 1996-2007 by Project Vogue.
+;;; Written by Yoshifumi "VOGUE" INOUE. (yosi@msn.com)
+;;;
+;;; @(#)$Id: //proj/evcl3/mainline/arch/generic/lisp/libm/float64/gen-float64-sign.lisp#1 $
+;;;
+;;; Description:
+;;;  This file contains implementation of float64-sign.
+;
+(in-package #:strict-math)
+
+#|
+ * From fdlibm (http://www.netlib.org/fdlibm/)
+/* @(#)s_copysign.c 5.1 93/09/24 */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice 
+ * is preserved.
+ * ====================================================
+ */
+
+/*
+FUNCTION
+<<copysign>>, <<copysignf>>---sign of <[y]>, magnitude of <[x]>
+
+INDEX
+        copysign
+INDEX
+        copysignf
+
+ANSI_SYNOPSIS
+        #include <math.h>
+        double copysign (double <[x]>, double <[y]>);
+        float copysignf (float <[x]>, float <[y]>);
+
+TRAD_SYNOPSIS
+        #include <math.h>
+        double copysign (<[x]>, <[y]>)
+        double <[x]>;
+        double <[y]>;
+
+        float copysignf (<[x]>, <[y]>)
+        float <[x]>;
+        float <[y]>;
+
+DESCRIPTION
+<<copysign>> constructs a number with the magnitude (absolute value)
+of its first argument, <[x]>, and the sign of its second argument,
+<[y]>.
+
+<<copysignf>> does the same thing; the two functions differ only in
+the type of their arguments and result.
+
+RETURNS
+<<copysign>> returns a <<double>> with the magnitude of
+<[x]> and the sign of <[y]>.
+<<copysignf>> returns a <<float>> with the magnitude of
+<[x]> and the sign of <[y]>.
+
+PORTABILITY
+<<copysign>> is not required by either ANSI C or the System V Interface
+Definition (Issue 2).
+
+*/
+
+/*
+ * copysign(double x, double y)
+ * copysign(x,y) returns a value with the magnitude of x and
+ * with the sign bit of y.
+ */
+|#
+(defun float64-sign (x y)
+    (declare (values double-float))
+    (declare (type double-float x y))
+  (multiple-value-bind (hx lx) (decode-float64 x)
+  (let ((hy (decode-float64 y)))
+    (encode-float64
+        (logior (logand hx #x7fffffff) (logand hy #x80000000))
+        lx ) ) ) )