--- icon-9.4.3.orig/config/gnu/rswitch.c
+++ icon-9.4.3/config/gnu/rswitch.c
@@ -0,0 +1,27 @@
+/*
+ * This is the co-expression context switch for the GNU system.
+ */
+
+/*
+ * coswitch
+ */
+
+coswitch(old_cs, new_cs, first)
+int *old_cs, *new_cs;
+int first;
+   {
+   asm("  movl 8(%ebp),%eax");
+   asm("  movl %esp,0(%eax)");
+   asm("  movl %ebp,4(%eax)");
+   asm("  movl 12(%ebp),%eax");
+   if (first == 0) {           /* this is the first activation */
+      asm("  movl 0(%eax),%esp");
+      asm("  movl $0,%ebp");
+      new_context(0, 0);
+      syserr("interp() returned in coswitch");
+      }
+   else {
+      asm("  movl 0(%eax),%esp");
+      asm("  movl 4(%eax),%ebp");
+      }
+   }