X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Fsxhash.lisp;h=2afbee678b51527c61a51c6eabb34e03704009e5;hb=f3f677703e37f5a335b3be7fa64f7748ad969517;hp=3ad33ca88ab753b6fc481fa282b5b7ba6eca0f9e;hpb=7a896fb715ceac43581a9a3835418e615002f9ec;p=sbcl.git

diff --git a/src/code/sxhash.lisp b/src/code/sxhash.lisp
index 3ad33ca..2afbee6 100644
--- a/src/code/sxhash.lisp
+++ b/src/code/sxhash.lisp
@@ -18,7 +18,7 @@
 ;;; order to avoid boxing.
 (deftransform sxhash ((x) (single-float))
   '(let* ((val (+ 0.0f0 x))
-	  (bits (single-float-bits val)))
+	  (bits (logand (single-float-bits val) #.(1- (ash 1 32)))))
      (logxor 66194023
 	     (sxhash (the fixnum
 			  (logand most-positive-fixnum
@@ -26,7 +26,7 @@
 					  (ash bits -7))))))))
 (deftransform sxhash ((x) (double-float))
   '(let* ((val (+ 0.0d0 x))
-	  (hi (double-float-high-bits val))
+	  (hi (logand (double-float-high-bits val) #.(1- (ash 1 32))))
 	  (lo (double-float-low-bits val))
 	  (hilo (logxor hi lo)))
      (logxor 475038542
@@ -39,8 +39,8 @@
 ;;; simple.
 (deftransform sxhash ((x) (fixnum))
   '(logand most-positive-fixnum
-	   (logxor (ash (logand x (ash most-positive-fixnum -4)) 4) 
-		   (ash x -1) ; to get sign bit into hash
+	   (logxor (ash (logand x (ash most-positive-fixnum -4)) 4)
+		   (logand (ash x -1) most-positive-fixnum) ; to get sign bit into hash
 		   361475658)))
 
 ;;; SXHASH of SIMPLE-BIT-VECTOR values is defined as a DEFTRANSFORM
@@ -68,7 +68,6 @@
 				'(- sb!vm:n-word-bits
 				    (mod length sb!vm:n-word-bits)))))
 		       (%raw-bits x i))))
-		 (declare (type (unsigned-byte 32) num))
 		 (mix result ,(ecase sb!c:*backend-byte-order*
 				(:little-endian
 				 '(logand num most-positive-fixnum))
@@ -76,7 +75,6 @@
 				 '(ash num (- sb!vm:n-lowtag-bits)))))))
 	   (declare (type index i end-1))
 	   (let ((num (%raw-bits x i)))
-	     (declare (type (unsigned-byte 32) num))
 	     (mixf result ,(ecase sb!c:*backend-byte-order*
 			     (:little-endian
 			      '(logand num most-positive-fixnum))
@@ -105,18 +103,29 @@
 (deftransform sxhash ((x) (symbol))
   (if #+sb-xc-host nil #-sb-xc-host (constant-lvar-p x)
       (sxhash (lvar-value x))
-      ;; Cache the value of the symbol's sxhash in the symbol-hash slot.
-      '(let ((result (symbol-hash x)))
-	;; 0 marks uninitialized slot. We can't use negative values
-	;; for the uninitialized slots since NIL might be located so
-	;; high in memory on some platforms that its SYMBOL-HASH
-	;; (which contains NIL itself) is a negative fixnum.
-	(if (= 0 result)
-	    (let ((sxhash (%sxhash-simple-string (symbol-name x))))
-	      ;; We could do a (logor sxhash #x10000000) to ensure
-	      ;; that we never store a 0 in the slot. However, it's
-	      ;; such an unlikely event (1/5e8?) that it makes more
-	      ;; sense to optimize for the common case...
-	      (%set-symbol-hash x sxhash)
-	      sxhash)
-	    result))))
+      (if (csubtypep (lvar-type x) (specifier-type 'null))
+	  ;; FIXME: this isn't in fact as optimized as it could be;
+	  ;; this does a memory load, whereas (because we know the
+	  ;; layout of NIL) we could simply take the address of NIL
+	  ;; (or the contents of NULL-TN) and mask off the appropriate
+	  ;; bits, since SYMBOL-HASH of NIL is also NIL's CDR, which
+	  ;; is NIL.  -- CSR, 2004-07-14
+	  '(symbol-hash x)
+	  ;; Cache the value of the symbol's sxhash in the symbol-hash
+	  ;; slot.
+	  '(let ((result (symbol-hash x)))
+	    ;; 0 marks uninitialized slot. We can't use negative
+	    ;; values for the uninitialized slots since NIL might be
+	    ;; located so high in memory on some platforms that its
+	    ;; SYMBOL-HASH (which contains NIL itself) is a negative
+	    ;; fixnum.
+	    (if (= 0 result)
+		(let ((sxhash (%sxhash-simple-string (symbol-name x))))
+		  ;; We could do a (logior sxhash #x10000000) to
+		  ;; ensure that we never store a 0 in the
+		  ;; slot. However, it's such an unlikely event
+		  ;; (1/5e8?) that it makes more sense to optimize for
+		  ;; the common case...
+		  (%set-symbol-hash x sxhash)
+		  sxhash)
+		result)))))