+
+define vmstack
+ vmstackinit
+ while $vmsp > vp->stack_base
+ nextframe
+ end
+end
+
+define inst
+ p scm_instruction_table[$arg0]
+end
+
+define gbt
+ call scm_display_backtrace (scm_make_stack(0x404,0x304), scm_current_error_port (), 0x704, 0x704, 0x704)
+end