5.6.2. Setting top of memory for a session

If you are working with an appropriate debug target, you can set the top_of_memory value on a temporary basis, that is for the current session, using the @top_of_memory register.


If you are using the default RVISS to simulate an ARM processor, this is not a suitable target for setting top_of_memory in this way because top_of_memory is set from a configuration file rather than from within RealView Debugger.

Setting a top of memory value for a RealView ICE connection

To set the value of top_of_memory for an ARM Integrator/AP board and ARM940T core, using RealView ICE:

  1. Connect to the RealView ICE debug target as described in Connecting to a debug target.

  2. Select Debug ? Memory/Register Operations ? Set Register... to display the Interactive Register Setting dialog box.

  3. Specify the register to be changed, @top_of_memory, and press Enter to see the current value, shown in Figure 5.2.

  4. Enter the new value, for example 0x40000, shown in Figure 5.2.

    Figure 5.2. Setting top of memory for session

    Setting top of memory for session
  5. Click Set to update the register contents. The Log display is updated to record the change.

  6. Click Close to close the dialog box.

  7. Select View ? Registers from the Code window main menu to display the Register pane.

    The Debug tab in the Register pane, displays the updated value, shown in the example in Figure 5.3.

    Figure 5.3. Changed settings in the Register pane

    Changed settings in the Register pane

The value of top_of_memory might be displayed in dark blue to show that it has changed since the last update.

If you set this value too low, loading an image to your target might generate a warning message in the Cmd tab:

Warning: No room for heap - could cause unpredictable behavior.

In-place editing

You can use in-place editing to change register contents in the Register pane, for example to change top_of_memory:

  1. Double-click in the value you want to change. The value is enclosed in a box with the characters highlighted to show they are selected (pending deletion).

  2. Type the new value, for example 0x80000.

  3. Press Enter.

If you press Escape before you press Enter, any changes you have made in the highlighted field are ignored.

For full details on setting top_of_memory for an ARM architecture-based target, see the chapter that describes memory mapping in RealView Debugger v1.8 User Guide.

Copyright © 2002-2005 ARM Limited. All rights reserved.ARM DUI 0181G