From 24511502828ede8f8b6acd27e23ff33c9186c418 Mon Sep 17 00:00:00 2001
From: Dirk Herrmann <dirk@dirk-herrmanns-seiten.de>
Date: Wed, 12 Jul 2000 07:38:06 +0000
Subject: [PATCH] * Fixed expt for the case of negative integer exponents.

---
 ice-9/ChangeLog  | 5 +++++
 ice-9/boot-9.scm | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/ice-9/ChangeLog b/ice-9/ChangeLog
index 02f1a1024..6160c876e 100644
--- a/ice-9/ChangeLog
+++ b/ice-9/ChangeLog
@@ -1,3 +1,8 @@
+2000-07-12  Dirk Herrmann  <D.Herrmann@tu-bs.de>
+
+	* boot-9.scm (expt):  Make sure that integer-expt is only called
+	if the exponent is a non-negative integer.
+
 2000-07-01  Mikael Djurfeldt  <mdj@thalamus.nada.kth.se>
 
 	* boot-9.scm (process-define-module): Bugfix: Only check the CDR
diff --git a/ice-9/boot-9.scm b/ice-9/boot-9.scm
index d190a771c..c1e578494 100644
--- a/ice-9/boot-9.scm
+++ b/ice-9/boot-9.scm
@@ -793,7 +793,7 @@
 (define expt
   (let ((integer-expt integer-expt))
     (lambda (z1 z2)
-      (cond ((exact? z2)
+      (cond ((and (integer? z2) (>= z2 0))
 	     (integer-expt z1 z2))
 	    ((and (real? z2) (real? z1) (>= z1 0))
 	     ($expt z1 z2))
-- 
2.20.1