diff --git a/scheme/ikarus.boot.prebuilt b/scheme/ikarus.boot.prebuilt
index 16337a0..9836d1a 100644
Binary files a/scheme/ikarus.boot.prebuilt and b/scheme/ikarus.boot.prebuilt differ
diff --git a/scheme/ikarus.compiler.altcogen.ss b/scheme/ikarus.compiler.altcogen.ss
index b3306e2..2dbf7af 100644
--- a/scheme/ikarus.compiler.altcogen.ss
+++ b/scheme/ikarus.compiler.altcogen.ss
@@ -487,11 +487,13 @@
   (define (alloc-check size)
     (E (make-shortcut
          (make-conditional ;;; PCB ALLOC-REDLINE
-           (make-primcall 'u<= 
-             (list (make-primcall 'int+ (list apr size)) 
-                   (make-primcall 'mref 
-                     (list pcr 
-                        (make-constant pcb-allocation-redline)))))
+           (make-primcall '>= 
+             (list (make-primcall 'int- 
+                      (list 
+                        (make-primcall 'mref 
+                          (list pcr (make-constant pcb-allocation-redline))) 
+                        apr))
+                   size))
            (make-primcall 'nop '())
            (make-primcall 'interrupt '()))
          (make-funcall 
diff --git a/scheme/last-revision b/scheme/last-revision
index d310a7d..941df00 100644
--- a/scheme/last-revision
+++ b/scheme/last-revision
@@ -1 +1 @@
-1488
+1489