X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/335c5470b52f0c9a387314a5323c4de57a137fb7..366717cfa0ff12fc544e9ee5031478e25aecf08d:/src/floatfns.c

diff --git a/src/floatfns.c b/src/floatfns.c
index fe107fb44f..79574e0a69 100644
--- a/src/floatfns.c
+++ b/src/floatfns.c
@@ -1,5 +1,6 @@
 /* Primitive operations on floating point for GNU Emacs Lisp interpreter.
-   Copyright (C) 1988, 1993, 1994, 1999 Free Software Foundation, Inc.
+   Copyright (C) 1988, 1993, 1994, 1999, 2002, 2003, 2004,
+                 2005 Free Software Foundation, Inc.
 
 This file is part of GNU Emacs.
 
@@ -15,8 +16,8 @@ GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with GNU Emacs; see the file COPYING.  If not, write to
-the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA.  */
+the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+Boston, MA 02110-1301, USA.  */
 
 
 /* ANSI C requires only these float functions:
@@ -255,13 +256,25 @@ DEFUN ("asin", Fasin, Sasin, 1, 1, 0,
   return make_float (d);
 }
 
-DEFUN ("atan", Fatan, Satan, 1, 1, 0,
-       doc: /* Return the inverse tangent of ARG.  */)
-     (arg)
-     register Lisp_Object arg;
+DEFUN ("atan", Fatan, Satan, 1, 2, 0,
+       doc: /* Return the inverse tangent of the arguments.
+If only one argument Y is given, return the inverse tangent of Y.
+If two arguments Y and X are given, return the inverse tangent of Y
+divided by X, i.e. the angle in radians between the vector (X, Y)
+and the x-axis.  */)
+     (y, x)
+     register Lisp_Object y, x;
 {
-  double d = extract_float (arg);
-  IN_FLOAT (d = atan (d), "atan", arg);
+  double d = extract_float (y);
+
+  if (NILP (x))
+    IN_FLOAT (d = atan (d), "atan", y);
+  else
+    {
+      double d2 = extract_float (x);
+
+      IN_FLOAT2 (d = atan2 (d, d2), "atan", y, x);
+    }
   return make_float (d);
 }
 
@@ -448,7 +461,8 @@ DEFUN ("expt", Fexpt, Sexpt, 2, 2, 0,
   CHECK_NUMBER_OR_FLOAT (arg1);
   CHECK_NUMBER_OR_FLOAT (arg2);
   if (INTEGERP (arg1)     /* common lisp spec */
-      && INTEGERP (arg2)) /* don't promote, if both are ints */
+      && INTEGERP (arg2)   /* don't promote, if both are ints, and */
+      && 0 <= XINT (arg2)) /* we are sure the result is not fractional */
     {				/* this can be improved by pre-calculating */
       EMACS_INT acc, x, y;	/* some binary powers of x then accumulating */
       Lisp_Object val;
@@ -456,7 +470,7 @@ DEFUN ("expt", Fexpt, Sexpt, 2, 2, 0,
       x = XINT (arg1);
       y = XINT (arg2);
       acc = 1;
-      
+
       if (y < 0)
 	{
 	  if (x == 1)
@@ -680,7 +694,7 @@ This is the same as the exponent of a float.  */)
   double f = extract_float (arg);
 
   if (f == 0.0)
-    value = -(VALMASK >> 1);
+    value = MOST_NEGATIVE_FIXNUM;
   else
     {
 #ifdef HAVE_LOGB
@@ -838,7 +852,8 @@ double_identity (d)
 }
 
 DEFUN ("ceiling", Fceiling, Sceiling, 1, 2, 0,
-       doc: /* Return the smallest integer no less than ARG.  (Round toward +inf.)
+       doc: /* Return the smallest integer no less than ARG.
+This rounds the value towards +inf.
 With optional DIVISOR, return the smallest integer no less than ARG/DIVISOR.  */)
      (arg, divisor)
      Lisp_Object arg, divisor;
@@ -847,7 +862,8 @@ With optional DIVISOR, return the smallest integer no less than ARG/DIVISOR.  */
 }
 
 DEFUN ("floor", Ffloor, Sfloor, 1, 2, 0,
-       doc: /* Return the largest integer no greater than ARG.  (Round towards -inf.)
+       doc: /* Return the largest integer no greater than ARG.
+This rounds the value towards -inf.
 With optional DIVISOR, return the largest integer no greater than ARG/DIVISOR.  */)
      (arg, divisor)
      Lisp_Object arg, divisor;
@@ -857,7 +873,12 @@ With optional DIVISOR, return the largest integer no greater than ARG/DIVISOR.
 
 DEFUN ("round", Fround, Sround, 1, 2, 0,
        doc: /* Return the nearest integer to ARG.
-With optional DIVISOR, return the nearest integer to ARG/DIVISOR.  */)
+With optional DIVISOR, return the nearest integer to ARG/DIVISOR.
+
+Rounding a value equidistant between two integers may choose the
+integer closer to zero, or it may prefer an even integer, depending on
+your machine.  For example, \(round 2.5\) can return 3 on some
+systems, but 2 on others.  */)
      (arg, divisor)
      Lisp_Object arg, divisor;
 {
@@ -962,6 +983,7 @@ float_error (signo)
   signal (SIGILL, float_error);
 #endif /* BSD_SYSTEM */
 
+  SIGNAL_THREAD_CHECK (signo);
   in_float = 0;
 
   Fsignal (Qarith_error, Fcons (float_error_arg, Qnil));
@@ -973,7 +995,7 @@ float_error (signo)
 #endif /* FLOAT_CATCH_SIGILL */
 
 #ifdef HAVE_MATHERR
-int 
+int
 matherr (x)
      struct exception *x;
 {
@@ -1007,7 +1029,7 @@ init_floatfns ()
 {
 #ifdef FLOAT_CATCH_SIGILL
   signal (SIGILL, float_error);
-#endif 
+#endif
   in_float = 0;
 }
 
@@ -1056,3 +1078,6 @@ syms_of_floatfns ()
   defsubr (&Sround);
   defsubr (&Struncate);
 }
+
+/* arch-tag: be05bf9d-049e-4e31-91b9-e6153d483ae7
+   (do not change this comment) */