X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Fnumbers.lisp;h=31455e82de91b828e1be7147762c38fd79f8fb7b;hb=fb24d88c8f97f1b344addab398fc54f62d8aa4ce;hp=525beb7585b0dd9f31648bb51cf4896f7f3b533c;hpb=0c7a7f68e66276a3c780a01d55f086a6f0aac929;p=sbcl.git

diff --git a/src/code/numbers.lisp b/src/code/numbers.lisp
index 525beb7..31455e8 100644
--- a/src/code/numbers.lisp
+++ b/src/code/numbers.lisp
@@ -363,9 +363,9 @@
                            (,op (imagpart x) (imagpart y))))
        (((foreach bignum fixnum ratio single-float double-float
                   #!+long-float long-float) complex)
-        (complex (,op x (realpart y)) (,op (imagpart y))))
+        (complex (,op x (realpart y)) (,op 0 (imagpart y))))
        ((complex (or rational float))
-        (complex (,op (realpart x) y) (imagpart x)))
+        (complex (,op (realpart x) y) (,op (imagpart x) 0)))
 
        (((foreach fixnum bignum) ratio)
         (let* ((dy (denominator y))
@@ -855,10 +855,10 @@ the first."
          ;; conversion.
          (multiple-value-bind (lo hi)
              (case '(dispatch-type y)
-               ('single-float
+               (single-float
                 (values most-negative-exactly-single-float-fixnum
                         most-positive-exactly-single-float-fixnum))
-               ('double-float
+               (double-float
                 (values most-negative-exactly-double-float-fixnum
                         most-positive-exactly-double-float-fixnum)))
            (if (<= lo y hi)
@@ -872,10 +872,10 @@ the first."
              ;; Likewise
              (multiple-value-bind (lo hi)
                  (case '(dispatch-type x)
-                   ('single-float
+                   (single-float
                     (values most-negative-exactly-single-float-fixnum
                             most-positive-exactly-single-float-fixnum))
-                   ('double-float
+                   (double-float
                     (values most-negative-exactly-double-float-fixnum
                             most-positive-exactly-double-float-fixnum)))
                (if (<= lo y hi)
@@ -1384,29 +1384,31 @@ the first."
            ((fixnum bignum)
             (bignum-gcd (make-small-bignum u) v))))))
 
-;;; From discussion on comp.lang.lisp and Akira Kurihara.
+;;;; from Robert Smith
 (defun isqrt (n)
   #!+sb-doc
   "Return the root of the nearest integer less than n which is a perfect
    square."
-  (declare (type unsigned-byte n) (values unsigned-byte))
-  ;; Theoretically (> n 7), i.e., n-len-quarter > 0.
-  (if (and (fixnump n) (<= n 24))
-      (cond ((> n 15) 4)
-            ((> n  8) 3)
-            ((> n  3) 2)
-            ((> n  0) 1)
-            (t 0))
-      (let* ((n-len-quarter (ash (integer-length n) -2))
-             (n-half (ash n (- (ash n-len-quarter 1))))
-             (n-half-isqrt (isqrt n-half))
-             (init-value (ash (1+ n-half-isqrt) n-len-quarter)))
-        (loop
-          (let ((iterated-value
-                 (ash (+ init-value (truncate n init-value)) -1)))
-            (unless (< iterated-value init-value)
-              (return init-value))
-            (setq init-value iterated-value))))))
+  (declare (type unsigned-byte n))
+  (cond
+    ((> n 24)
+     (let* ((n-fourth-size (ash (1- (integer-length n)) -2))
+            (n-significant-half (ash n (- (ash n-fourth-size 1))))
+            (n-significant-half-isqrt (isqrt n-significant-half))
+            (zeroth-iteration (ash n-significant-half-isqrt n-fourth-size))
+            (qr (multiple-value-list (floor n zeroth-iteration)))
+            (first-iteration (ash (+ zeroth-iteration (first qr)) -1)))
+       (cond ((oddp (first qr))
+              first-iteration)
+             ((> (expt (- first-iteration zeroth-iteration) 2) (second qr))
+              (1- first-iteration))
+             (t
+              first-iteration))))
+    ((> n 15) 4)
+    ((> n  8) 3)
+    ((> n  3) 2)
+    ((> n  0) 1)
+    ((= n  0) 0)))
 
 ;;;; miscellaneous number predicates