Registers Window Introduction

The Registers window displays registers from a selected processor. Multiple Registers windows may be opened.

To open the Registers window, select View|Registers on the menu bar or click on the Registers icon on the toolbar.

Registers window

Register Groups

The left side of the Registers window contains groups of registers that are available for viewing.

Register List

The right side of the Registers window displays the list of processor registers contained in the selected register group.  The number of columns displayed varies based on the register group selected.  Columns are resizable.

Name.  Displays the register name.  The tooltip for a register name gives a description of the register.

Value.  Displays the register value.  Register values are displayed in hexadecimal except for floating point registers which are displayed in scientific notation.   

The tooltip for a register value varies depending on the register type. If the register contains sub-fields, then the field names and values are displayed. For instance, the tooltip for EFLAGS displays all the processor flags and their values. The tooltip for floating point registers displays the value in hex. The tooltip for segment registers (CS, SS, etc.) displays the base, limit, and access rights associated with that register

Number.  This column is only present when an MSR register group is displayed.  It displays the MSR number.  

Description.  This column is only present when an MSR register group is displayed.  It displays a description of the MSR.  

Registers Window Menu

The Registers menu displays on the menu bar after a Registers window has been opened. It is also displayed when right-clicking in the Register List area of the Registers window

Edit.  Edits a register value.  Double left-clicking has the same effect.  See Editing a Register Value below.

Expand.  Displays a register value in binary.  See Expanding a Register Value below.

Remove. Removes the currently selected register from the Register list.  The register can be restored by selecting Restore Defaults.

Open Code Window. Opens a Code Window to the address specified by the selected register value.

Open Memory Window. Opens a Memory Window to the address specified by the selected register value.

Peek Memory. Read 32 bits of memory using the register value as a memory address.

Show Description. Shows / hides the Description columns.

Copy to User Page. Copies the currently selected register to the User register list.  This is useful for creating a custom register list.

Restore Defaults.  Restores the default register lists.

Viewpoint. Selects which processor’s registers are displayed.  This menu item is only present for multi-processor targets.  See Processor Selection below.

Editing a Register Value

To edit a register value, either select Edit from the menu, or double click on a register value.  Enter the new value, and either press Enter, or cursor from the field to write the value to the processor.  Press Esc to cancel an edit

If a value is being edited when either go or step is selected, the edit is terminated, the value is written to the processor, and then the go or step operation is performed.  Register values cannot be edited while the processor is running

Read-only register values are displayed in gray. These values may not be edited. Write-only register values are displayed as a string of asterisks. To edit a write-only value, type over the asterisks. When the edit is terminated, the value is written to the processor and the register value changes back to asterisks.

Register values can be copied and pasted by using the Edit menu item on the menu bar to copy and paste a value.

Register values may be displayed and edited in binary by opening the Expand window.

Expanding a Register Value

To expand a register to view individual bits, select Expand from the menu.  The Expand dialog will open.

Expand dialog

Each bit is displayed as a button with its value displayed in binary. The name of each bit (if any) is displayed above the button. Multi-bit fields have the same name above each button. Bit names are shortened to a maximum of three characters. The flyover help for a bit displays a longer description of that bit.

Bit numbers, along with the value of each nibble in hex, are displayed beneath the buttons.

To change the value of a bit, click on the bit, or cursor to a bit and press 0 or 1. To write the value to the processor, press the OK button.

Note: To display a register's bits and have them remain always viewable, open the Watch window, and drag the register name into it. Click on the "+" sign to the left of the register name to display the register's bits.

Processor Selection

The processor is selected by selecting Viewpoint in the menu, and then specifying a processor.  On single processor targets, this menu item is not present.

The default processor selection is Track Viewpoint.  When selected, the Registers window automatically switches processors when the viewpoint processor is changed (in the Viewpoint window).

The currently selected processor is displayed in the Title bar.  If Track Viewpoint is enabled, then a '*' character is displayed.

Register Value Coloring

Modified registers are colored green. This indicates that the register's value has changed as a result of a go or step operation or that the value has been edited.

Read-only register values are displayed in gray rather than black. Write-only register values are displayed as a string of asterisks rather than numbers.

Register coloring can be customized by selecting Options|Preferences|Colors.