From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <cgen-return-1245-listarch-cgen=sources.redhat.com@sources.redhat.com>
Received: (qmail 14722 invoked by alias); 9 Jan 2003 03:45:19 -0000
Mailing-List: contact cgen-help@sources.redhat.com; run by ezmlm
Precedence: bulk
List-Subscribe: <mailto:cgen-subscribe@sources.redhat.com>
List-Archive: <http://sources.redhat.com/ml/cgen/>
List-Post: <mailto:cgen@sources.redhat.com>
List-Help: <mailto:cgen-help@sources.redhat.com>, <http://sources.redhat.com/lists.html#faqs>
Sender: cgen-owner@sources.redhat.com
Received: (qmail 14702 invoked from network); 9 Jan 2003 03:45:18 -0000
Received: from unknown (HELO neon-gw.transmeta.com) (63.209.4.196)
  by 209.249.29.67 with SMTP; 9 Jan 2003 03:45:18 -0000
Received: (from root@localhost)
	by neon-gw.transmeta.com (8.9.3/8.9.3) id TAA17359;
	Wed, 8 Jan 2003 19:45:01 -0800
Received: from mailhost.transmeta.com(10.1.1.15) by neon-gw.transmeta.com via smap (V2.1)
	id xma017338; Wed, 8 Jan 03 19:44:44 -0800
Received: from casey.transmeta.com (casey.transmeta.com [10.10.25.22])
	by deepthought.transmeta.com (8.11.6/8.11.6) with ESMTP id h093in306970;
	Wed, 8 Jan 2003 19:44:49 -0800 (PST)
Received: (from dje@localhost) by casey.transmeta.com (8.9.3/8.7.3) id TAA13187; Wed, 8 Jan 2003 19:44:49 -0800
From: Doug Evans <dje@transmeta.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Message-ID: <15900.61489.570002.368127@casey.transmeta.com>
Date: Thu, 09 Jan 2003 03:45:00 -0000
To: Ben Elliston <bje@redhat.com>
Cc: cgen@sources.redhat.com
Subject: decoder bug fix
In-Reply-To: <m3znqbm365.fsf@scooby.brisbane.redhat.com>
References: <m3znqbm365.fsf@scooby.brisbane.redhat.com>
X-SW-Source: 2003-q1/txt/msg00006.txt.bz2

Ben Elliston writes:
 > I am committing the following patch (written by Graydon Hoare last
 > year) that fixes an edge condition in the (-gen-decoder-switch) logic.
 > 
 > Ben
 > 
 > 2003-01-09  Ben Elliston  <bje@redhat.com>
 > 
 >         From Graydon Hoare <graydon@redhat.com>:
 >         * utils-sim.scm (-gen-decoder-switch): Fix edge condition 
 >         empty ISAs.
 > 
 > Index: utils-sim.scm
 > ===================================================================
 > RCS file: /cvs/src/src/cgen/utils-sim.scm,v
 > retrieving revision 1.8
 > diff -u -p -r1.8 utils-sim.scm
 > --- utils-sim.scm       20 Dec 2002 07:58:32 -0000      1.8
 > +++ utils-sim.scm       9 Jan 2003 03:05:01 -0000
 > @@ -938,9 +938,11 @@
 >                         ";\n"
 >                         indent "  val = "))
 >         (string-append indent "  unsigned int val = "))
 > -   (-gen-decode-bits (dtable-guts-bitnums table-guts)
 > -                    (dtable-guts-startbit table-guts)
 > -                    (dtable-guts-bitsize table-guts) "insn" lsb0?)
 > +   (if (< (length (dtable-guts-bitnums table-guts)) 1)
 > +       "0"
 > +       (-gen-decode-bits (dtable-guts-bitnums table-guts)
 > +                        (dtable-guts-startbit table-guts)
 > +                        (dtable-guts-bitsize table-guts) "insn" lsb0?))
 >     ";\n"
 >     indent "  switch (val)\n"
 >     indent "  {\n"
 > <

This is ok with me,
though I can make an argument to fix -gen-decode-bits instead.
Without having tried it, seems like this should work.

--- utils-sim.scm.~1~	Sun Dec 22 14:57:08 2002
+++ utils-sim.scm	Wed Jan  8 19:41:41 2003
@@ -550,8 +550,7 @@
 			 pos (+ 1 count)
 			 (cdr bitnums)))))))
     (string-append
-     "("
-     (string-drop 3
+     "(0"
 		  (string-map
 		   (lambda (group)
 		     (let* ((first (car group))
@@ -569,7 +568,7 @@
 		      ") & ("
 		      (number->string (- (integer-expt 2 bits) 1))
 		      " << " (number->string pos) "))")))
-		   groups))
+		   groups)
      ")"))
 )
 

[suitably re-indented of course]