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10.13. Memory region attributes

Memory region attributes allow you to describe special handling required by regions of your target's memory. gdb uses attributes to determine whether to allow certain types of memory accesses; whether to use specific width accesses; and whether to cache target memory.

Defined memory regions can be individually enabled and disabled. When a memory region is disabled, gdb uses the default attributes when accessing memory in that region. Similarly, if no memory regions have been defined, gdb uses the default attributes when accessing all memory.

When a memory region is defined, it is given a number to identify it; to enable, disable, or remove a memory region, you specify that number.

mem lower upper attributes

Define memory region bounded by lower and upper with attributes attributes…. Note that upper == 0 is a special case: it is treated as the the target's maximum memory address. (0xffff on 16 bit targets, 0xffffffff on 32 bit targets, etc.)

delete mem nums

Remove memory regions nums….

disable mem nums

Disable memory regions nums…. A disabled memory region is not forgotten. It may be enabled again later.

enable mem nums

Enable memory regions nums….

info mem

Print a table of all defined memory regions, with the following columns for each region.

Memory Region Number, Enabled or Disabled.

Enabled memory regions are marked with y. Disabled memory regions are marked with n.

Lo Address

The address defining the inclusive lower bound of the memory region.

Hi Address

The address defining the exclusive upper bound of the memory region.


The list of attributes set for this memory region.

10.13.1. Attributes Memory Access Mode

The access mode attributes set whether gdb may make read or write accesses to a memory region.

While these attributes prevent gdb from performing invalid memory accesses, they do nothing to prevent the target system, I/O DMA, etc. from accessing memory.


Memory is read only.


Memory is write only.


Memory is read/write. This is the default. Memory Access Size

The acccess size attributes tells gdb to use specific sized accesses in the memory region. Often memory mapped device registers require specific sized accesses. If no access size attribute is specified, gdb may use accesses of any size.


Use 8 bit memory accesses.


Use 16 bit memory accesses.


Use 32 bit memory accesses.


Use 64 bit memory accesses. Data Cache

The data cache attributes set whether gdb will cache target memory. While this generally improves performance by reducing debug protocol overhead, it can lead to incorrect results because gdb does not know about volatile variables or memory mapped device registers.


Enable gdb to cache target memory.


Disable gdb from caching target memory. This is the default.

  Published under the terms of the GNU General Public License Design by Interspire