1 files changed, 81 insertions, 0 deletions
diff --git a/c/src/lib/libbsp/m68k/mvme167/startup/bspclean.c b/c/src/lib/libbsp/m68k/mvme167/startup/bspclean.c
new file mode 100644
index 0000000000..753c378cae
--- /dev/null
+++ b/c/src/lib/libbsp/m68k/mvme167/startup/bspclean.c
@@ -0,0 +1,81 @@
+/*  bspclean.c
+ *
+ *  These routines return control to 167Bug after a normal exit from the
+ *  application.
+ *
+ *  COPYRIGHT (c) 1989-1998.
+ *  On-Line Applications Research Corporation (OAR).
+ *  Copyright assigned to U.S. Government, 1994.
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.OARcorp.com/rtems/license.html.
+ *
+ *  Modifications of respective RTEMS files:
+ *  Copyright (c) 1998, National Research Council of Canada
+ *
+ *  $Id$
+ */
+
+#include <rtems.h>
+#include <bsp.h>
+#include <page_table.h>
+
+/*
+ *  bsp_return_to_monitor_trap
+ *
+ *  Switch the VBR back to ROM and make a .RETURN syscall to return control to
+ *  167 Bug. If 167Bug ever returns, restart the application.
+ *
+ *  Input parameters: NONE
+ *
+ *  Output parameters: NONE
+ *
+ *  Return values: NONE
+ */
+static void bsp_return_to_monitor_trap( void )
+{
+  extern void start( void );
+
+  register volatile void *start_addr;
+
+  page_table_teardown();
+
+  lcsr->intr_ena = 0;               /* disable interrupts */
+  m68k_set_vbr(0xFFE00000);         /* restore 167Bug vectors */
+  asm volatile( "trap   #15         /* trap to 167Bug */
+                 .short 0x63" );    /* return to 167Bug (.RETURN) */
+  
+  /* restart program */
+  start_addr = start;
+  asm volatile( "jmp %0@" : "=a" (start_addr) : "0" (start_addr) );
+}
+
+/*
+ *  bsp_cleanup
+ *
+ *  This code was copied from other MC680x0 MVME BSPs.
+ *  Our guess is that someone was concerned about the CPU no longer being in
+ *  supervisor mode when they got here. This function forces the CPU back to
+ *  supervisor mode so the VBR may be changed. It places the address of the
+ *  function that makes a 167Bug .RETURN syscall in the trap 13 entry in the
+ *  exception vector, and then issues a trap 13 call. It is also possible that
+ *  the code was copied from some other OS that does run tasks in user mode.
+ *  In any case, it appears to be a bit of paranoia, and could lead to 
+ *  problems if 167Bug is invoked before we get to switch the VBR back to
+ *  167Bug because trap 13 is documented as being reserved for the internal
+ *  use of the debugger.
+ *
+ *  Prototyped in rtems/c/src/lib/libbsp/m68k/mvme167/include/bsp.h
+ *
+ *  Input parameters: NONE
+ *
+ *  Output parameters: NONE
+ *
+ *  Return values: DOES NOT RETURN
+ */
+void bsp_cleanup( void )
+{
+   M68Kvec[ 45 ] = bsp_return_to_monitor_trap;
+   asm volatile( "trap #13" );
+}