Nios® II Software Developer Handbook

ID 683525
Date 8/28/2023
Public
Document Table of Contents

3.4.4.4.2. Linker Regions

At the bottom of the Linker Script tab, the Linker Memory Regions table shows all defined linker regions. Each row of the table shows one linker region, with its address range, memory device name, size, and offset into the selected memory device.

You reassign a defined linker region to a different memory device by selecting a different device name in the Memory Device Name column. The Size and Offset columns are editable. You can also edit the list of linker regions using the following buttons located next to the linker region table.

Note: Ensure that you specify the correct base address and memory size. If the base address or size of an external memory changes, you must edit the BSP manually to match. The SBT does not automatically detect changes in external memory devices, even if you update the BSP by creating a new settings file.
Table 5.  Linker Memory Regions Table Buttons
Name Description
Add Adds a linker region in unused space on any existing device. The Add button opens the Add Memory Region dialog box, where you specify the memory device, the new memory region name, the region size, and the region's offset from the device base address.
Remove Removes a linker region definition. Removing a region frees the region's memory space to be used for other regions.
Add Memory Device Creates a linker region representing a memory device that is outside the hardware system. The button opens the Add Memory Device dialog box, where you can specify the device name, memory size, and base address. After you add the device, it appears in the linker region table, the Memory Device Usage Table dialog box, and the Memory Map dialog box. This functionality is equivalent to the add_memory_device Tcl command.
  • Restore Defaults—restores the memory regions to the default configuration set up at the time of BSP creation.
  • Memory Usage—Opens the Memory Device Usage Table. The Memory Device Usage Table allows you to view memory device usage by defined memory region. As memory regions are added, removed, and adjusted, each device's free memory, used memory, and percentage of available memory are updated. The rightmost column is a graphical representation of the device’s usage, according to the memory regions assigned to it.
  • Memory Map—Opens the Memory Map dialog box. The memory map allows you to view a map of system memory in the processor address space. The Device table is a read-only reference showing memories in the hardware system that are hosted by the selected processor. Devices are listed in memory address order.

    To the right of the Device table is a graphical representation of the processor's memory space, showing the locations of devices in the table. Gaps indicate unmapped address space.

Note: This gap representation is not to scale.