From: Chris Hanson <org/chris-hanson/cph>
Date: Thu, 21 May 1987 15:06:54 +0000 (+0000)
Subject: Fix bug in expansion of interpreter-call:enclose.  When the number of
X-Git-Tag: 20090517-FFI~13490
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=6372a5b10dde8f1eb187ac6d711526db82ddce8e;p=mit-scheme.git

Fix bug in expansion of interpreter-call:enclose.  When the number of
things being enclosed is sufficiently large, the generator was forcing
the allocation of D0 for use as a loop counter.  This had the
unfortunate side effect that if D0 contained some unboxed object then
that object would be flushed to memory.
---

diff --git a/v7/src/compiler/machines/bobcat/lapgen.scm b/v7/src/compiler/machines/bobcat/lapgen.scm
index 31bc41861..874473353 100644
--- a/v7/src/compiler/machines/bobcat/lapgen.scm
+++ b/v7/src/compiler/machines/bobcat/lapgen.scm
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/compiler/machines/bobcat/lapgen.scm,v 1.165 1987/05/18 16:23:57 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/compiler/machines/bobcat/lapgen.scm,v 1.166 1987/05/21 15:06:54 cph Exp $
 
 Copyright (c) 1987 Massachusetts Institute of Technology
 
@@ -715,9 +715,11 @@ MIT in each case. |#
 			 '(@A+ 5))
       ,@(generate-n-times number-pushed 5 '(MOVE L (@A+ 7) (@A+ 5))
 	  (lambda (generator)
-	    `(,@(clear-registers! d0)
-	      ,@(generator 0)))))
+	    (generator (allocate-temporary-register! 'DATA)))))
 #| Alternate sequence which minimizes code size.
+   DO NOT USE THIS!  The `clear-registers!' call does not distinguish between
+   registers containing objects and registers containing unboxed things, and
+   as a result can write unboxed stuff to memory.
     `(,@(clear-registers! a0 a1 d0)
       (MOVE W (& ,number-pushed) (D 0))
       (JSR ,entry:compiler-enclose))