(/ N) now returns the reciprocal of N

This is more compatible with Common Lisp and XEmacs (Bug#21690).  See:
http://lists.gnu.org/archive/html/emacs-devel/2015-10/msg01053.html
* lisp/color.el (color-hue-to-rgb, color-hsl-to-rgb)
(color-xyz-to-srgb, color-xyz-to-lab):
* lisp/emacs-lisp/cl-extra.el (cl-float-limits):
* lisp/net/shr-color.el (shr-color-hue-to-rgb)
(shr-color-hsl-to-rgb-fractions):
Exploit the change to simplify the code a bit.
* lisp/emacs-lisp/bytecomp.el (byte-compile-quo):
Don’t complain about single-argument calls to ‘/’.
* src/data.c (arith_driver, float_arith_driver):
Implement the change.

4 files changed, 15 insertions, 15 deletions

diff --git a/lisp/color.el b/lisp/color.el
index d572222021b..97656ca9e33 100644
--- a/lisp/color.el
+++ b/lisp/color.el
@@ -93,7 +93,7 @@ resulting list."
   "Compute hue from V1 and V2 H.
 Used internally by `color-hsl-to-rgb'."
   (cond
-   ((< h (/ 1.0 6))   (+ v1 (* (- v2 v1) h 6.0)))
+   ((< h (/ 6.0))     (+ v1 (* (- v2 v1) h 6.0)))
    ((< h 0.5)         v2)
    ((< h (/ 2.0 3))   (+ v1 (* (- v2 v1) (- (/ 2.0 3) h) 6.0)))
    (t                 v1)))
@@ -110,9 +110,9 @@ inclusive."
                  (- (+ L S) (* L S))))
            (m1 (- (* 2.0 L) m2)))
       (list
-       (color-hue-to-rgb m1 m2 (mod (+ H (/ 1.0 3)) 1))
+       (color-hue-to-rgb m1 m2 (mod (+ H (/ 3.0)) 1))
        (color-hue-to-rgb m1 m2 H)
-       (color-hue-to-rgb m1 m2 (mod (- H (/ 1.0 3)) 1))))))
+       (color-hue-to-rgb m1 m2 (mod (- H (/ 3.0)) 1))))))
 
 (defun color-complement-hex (color)
   "Return the color that is the complement of COLOR, in hexadecimal format."
@@ -199,13 +199,13 @@ RED, GREEN and BLUE should be between 0.0 and 1.0, inclusive."
         (b (+ (* 0.0556434 X) (* -0.2040259 Y) (* 1.0572252 Z))))
     (list (if (<= r 0.0031308)
               (* 12.92 r)
-            (- (* 1.055 (expt r (/ 1 2.4))) 0.055))
+            (- (* 1.055 (expt r (/ 2.4))) 0.055))
           (if (<= g 0.0031308)
               (* 12.92 g)
-            (- (* 1.055 (expt g (/ 1 2.4))) 0.055))
+            (- (* 1.055 (expt g (/ 2.4))) 0.055))
           (if (<= b 0.0031308)
               (* 12.92 b)
-            (- (* 1.055 (expt b (/ 1 2.4))) 0.055)))))
+            (- (* 1.055 (expt b (/ 2.4))) 0.055)))))
 
 (defconst color-d65-xyz '(0.950455 1.0 1.088753)
   "D65 white point in CIE XYZ.")
@@ -222,13 +222,13 @@ conversion.  If omitted or nil, use `color-d65-xyz'."
              (yr (/ Y Yr))
              (zr (/ Z Zr))
              (fx (if (> xr color-cie-ε)
-                     (expt xr (/ 1 3.0))
+                     (expt xr (/ 3.0))
                    (/ (+ (* color-cie-κ xr) 16) 116.0)))
              (fy (if (> yr color-cie-ε)
-                     (expt yr (/ 1 3.0))
+                     (expt yr (/ 3.0))
                    (/ (+ (* color-cie-κ yr) 16) 116.0)))
              (fz (if (> zr color-cie-ε)
-                     (expt zr (/ 1 3.0))
+                     (expt zr (/ 3.0))
                    (/ (+ (* color-cie-κ zr) 16) 116.0))))
         (list
          (- (* 116 fy) 16)                  ; L
diff --git a/lisp/emacs-lisp/bytecomp.el b/lisp/emacs-lisp/bytecomp.el
index 6f7ba3353f6..d138effcd9d 100644
--- a/lisp/emacs-lisp/bytecomp.el
+++ b/lisp/emacs-lisp/bytecomp.el
@@ -3617,8 +3617,8 @@ discarding."
 
 (defun byte-compile-quo (form)
   (let ((len (length form)))
-    (cond ((<= len 2)
-           (byte-compile-subr-wrong-args form "2 or more"))
+    (cond ((< len 2)
+           (byte-compile-subr-wrong-args form "1 or more"))
           ((= len 3)
            (byte-compile-two-args form))
           (t
diff --git a/lisp/emacs-lisp/cl-extra.el b/lisp/emacs-lisp/cl-extra.el
index dddfca7ae83..afa021dffc7 100644
--- a/lisp/emacs-lisp/cl-extra.el
+++ b/lisp/emacs-lisp/cl-extra.el
@@ -497,7 +497,7 @@ This sets the values of: `cl-most-positive-float', `cl-most-negative-float',
         (setq cl-least-positive-normalized-float y
               cl-least-negative-normalized-float (- y))
         ;; Divide down until value underflows to zero.
-        (setq x (/ 1 z) y x)
+        (setq x (/ z) y x)
         (while (condition-case _ (> (/ x 2) 0) (arith-error nil))
           (setq x (/ x 2)))
         (setq cl-least-positive-float x
diff --git a/lisp/net/shr-color.el b/lisp/net/shr-color.el
index 482f829707d..f8d358c27b3 100644
--- a/lisp/net/shr-color.el
+++ b/lisp/net/shr-color.el
@@ -211,7 +211,7 @@ This will convert \"80 %\" to 204, \"100 %\" to 255 but \"123\" to \"123\"."
   "Convert X Y H to RGB value."
   (when (< h 0) (incf h))
   (when (> h 1) (decf h))
-  (cond ((< h (/ 1 6.0)) (+ x (* (- y x) h 6)))
+  (cond ((< h (/ 6.0)) (+ x (* (- y x) h 6)))
         ((< h 0.5) y)
         ((< h (/ 2.0 3.0)) (+ x (* (- y x) (- (/ 2.0 3.0) h) 6)))
         (t x)))
@@ -223,9 +223,9 @@ This will convert \"80 %\" to 204, \"100 %\" to 255 but \"123\" to \"123\"."
         (setq m2 (* l (+ s 1)))
         (setq m2 (- (+ l s) (* l s))))
     (setq m1 (- (* l 2) m2))
-    (list (shr-color-hue-to-rgb m1 m2 (+ h (/ 1 3.0)))
+    (list (shr-color-hue-to-rgb m1 m2 (+ h (/ 3.0)))
           (shr-color-hue-to-rgb m1 m2 h)
-          (shr-color-hue-to-rgb m1 m2 (- h (/ 1 3.0))))))
+          (shr-color-hue-to-rgb m1 m2 (- h (/ 3.0))))))
 
 (defun shr-color->hexadecimal (color)
   "Convert any color format to hexadecimal representation.