Index: kernel/arch/ia32/src/userspace.c
===================================================================
--- kernel/arch/ia32/src/userspace.c	(revision 4a537dda1680cfd9fd57ba877d36d641060c8f7f)
+++ kernel/arch/ia32/src/userspace.c	(revision 3cc110fd26aa526528a9c7a4962a95fc10e58feb)
@@ -70,6 +70,6 @@
 		"movl %[uarg], %%eax\n"
 		
-		/* %ebx is defined to hold pcb_ptr - set it to 0 */
-		"xorl %%ebx, %%ebx\n"
+		/* %edi is defined to hold pcb_ptr - set it to 0 */
+		"xorl %%edi, %%edi\n"
 		
 		"iret\n"