From: Chris Hanson <org/chris-hanson/cph>
Date: Wed, 16 May 1990 22:42:55 +0000 (+0000)
Subject: In bignum division when doing add-back because initial guess was too
X-Git-Tag: 20090517-FFI~11404
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=5ef592f30c465e05653b19ac78e67317fac7c481;p=mit-scheme.git

In bignum division when doing add-back because initial guess was too
large: if the add-back causes a carry it must be discarded.
---

diff --git a/v7/src/microcode/bignum.c b/v7/src/microcode/bignum.c
index f6c0bf5f7..93bc76838 100644
--- a/v7/src/microcode/bignum.c
+++ b/v7/src/microcode/bignum.c
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/bignum.c,v 9.30 1990/02/11 22:34:00 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/bignum.c,v 9.31 1990/05/16 22:42:04 cph Exp $
 
 Copyright (c) 1989, 1990 Massachusetts Institute of Technology
 
@@ -1208,7 +1208,10 @@ bignum_divide_subtract (v_start, v_end, guess, u_start)
 	}
     }
   if (carry == 1)
-    (*u_scan) += 1;
+    {
+      bignum_digit_type sum = ((*u_scan) + carry);
+      (*u_scan) = ((sum < BIGNUM_RADIX) ? sum : (sum - BIGNUM_RADIX));
+    }
   return (guess - 1);
 }
 
diff --git a/v7/src/microcode/version.h b/v7/src/microcode/version.h
index 23c4c4abd..e87010dbe 100644
--- a/v7/src/microcode/version.h
+++ b/v7/src/microcode/version.h
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/Attic/version.h,v 11.30 1990/04/17 22:20:34 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/Attic/version.h,v 11.31 1990/05/16 22:42:55 cph Exp $
 
 Copyright (c) 1988, 1989, 1990 Massachusetts Institute of Technology
 
@@ -46,7 +46,7 @@ MIT in each case. */
 #define VERSION		11
 #endif
 #ifndef SUBVERSION
-#define SUBVERSION	30
+#define SUBVERSION	31
 #endif
 
 #ifndef UCODE_TABLES_FILENAME
diff --git a/v8/src/microcode/version.h b/v8/src/microcode/version.h
index eaf287986..3fe71f40c 100644
--- a/v8/src/microcode/version.h
+++ b/v8/src/microcode/version.h
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v8/src/microcode/version.h,v 11.30 1990/04/17 22:20:34 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v8/src/microcode/version.h,v 11.31 1990/05/16 22:42:55 cph Exp $
 
 Copyright (c) 1988, 1989, 1990 Massachusetts Institute of Technology
 
@@ -46,7 +46,7 @@ MIT in each case. */
 #define VERSION		11
 #endif
 #ifndef SUBVERSION
-#define SUBVERSION	30
+#define SUBVERSION	31
 #endif
 
 #ifndef UCODE_TABLES_FILENAME