[Sbcl-commits] CVS: sbcl/contrib/sb-rotate-byte compiler.lisp,1.4,1.5

[Juho S. <js...@us...>]

Update of /cvsroot/sbcl/sbcl/contrib/sb-rotate-byte
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv4473/contrib/sb-rotate-byte

Modified Files:
	compiler.lisp 
Log Message:
0.9.4.8:
	Add a fallback implementation of SB-ROTATE-BYTE:%UNSIGNED-32-ROTATE-BYTE
        for platforms without the optimized VOPs, that isn't as pessimal as
        the generic %ROTATE-BYTE. About 70x speedup for SB-MD5 on x86-64.


Index: compiler.lisp
===================================================================
RCS file: /cvsroot/sbcl/sbcl/contrib/sb-rotate-byte/compiler.lisp,v
retrieving revision 1.4
retrieving revision 1.5
diff -u -d -r1.4 -r1.5
--- compiler.lisp	14 Jul 2005 16:30:09 -0000	1.4
+++ compiler.lisp	26 Aug 2005 22:19:12 -0000	1.5
@@ -56,3 +56,15 @@
   ;; FIXME: What happens when, as here, the two type specifiers for
   ;; COUNT overlap?  Which gets to run first?
   '(%unsigned-32-rotate-byte count integer))
+
+;; Generic implementation for platforms that don't supply VOPs for 32-bit
+;; rotate.
+#-(or x86 ppc)
+(deftransform %unsigned-32-rotate-byte ((.count. .integer.)
+                                        ((integer -31 31)
+                                         (unsigned-byte 32)) *)
+  '(if (< .count. 0)
+       (logior (ldb (byte 32 0) (ash .integer. (+ .count. 32)))
+               (ash .integer. .count.))
+       (logior (ldb (byte 32 0) (ash .integer. .count.))
+               (ash .integer. (- .count. 32)))))