Add a few benchmarks for R6RS fixnum arithmetic

* benchmark-suite/benchmarks/r6rs-arithmetic.bm: New file containing
  some benchmarks for R6RS fixnum operations.
* benchmark-suite/Makefile.am (SCM_BENCHMARKS): Add
  benchmarks/r6rs-arithmetic.

benchmark-suite/Makefile.am

@@ -6,6 +6,7 @@ SCM_BENCHMARKS = benchmarks/0-reference.bm		\
                  benchmarks/if.bm			\
                  benchmarks/logand.bm			\
 		 benchmarks/ports.bm			\
+		 benchmarks/r6rs-arithmetic.bm		\
 		 benchmarks/read.bm			\
 		 benchmarks/srfi-1.bm			\
 		 benchmarks/srfi-13.bm			\

benchmark-suite/benchmarks/r6rs-arithmetic.bm

@@ -0,0 +1,35 @@
+;;; -*- mode: scheme; coding: utf-8; -*-
+;;; R6RS-specific arithmetic benchmarks
+;;;
+;;; Copyright (C) 2011 Free Software Foundation, Inc.
+;;;
+;;; This library is free software; you can redistribute it and/or
+;;; modify it under the terms of the GNU Lesser General Public
+;;; License as published by the Free Software Foundation; either
+;;; version 3 of the License, or (at your option) any later version.
+;;;
+;;; This library is distributed in the hope that it will be useful,
+;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;;; Lesser General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU Lesser General Public
+;;; License along with this library. If not, see
+;;; <http://www.gnu.org/licenses/>.
+
+(define-module (benchmarks r6rs-arithmetic)
+  #:use-module (benchmark-suite lib)
+  #:use-module (rnrs arithmetic fixnums))
+
+
+(with-benchmark-prefix "fixnum"
+
+  (benchmark "fixnum? [yes]" 1e7
+    (fixnum? 10000))
+
+  (let ((n (+ most-positive-fixnum 100)))
+    (benchmark "fixnum? [no]" 1e7
+      (fixnum? n)))
+
+  (benchmark "fxxor [2]" 1e7
+    (fxxor 3 8)))