Specifications

182 www.xilinx.com Embedded System Tools Guide (EDK 6.2i)

1-800-255-7778 UG111 (v1.4) January 30, 2004

Chapter 12: GNU Debugger

At this point, mb-gdb is connected to XMD and controls the debugging. The simple but

powerful GUI can be used to debug the program, read and write memory and registers.

GDB Built-in Simulator

The MicroBlaze debugger provides an instruction set simulator, which can be used to

debug programs that do not access any peripherals. This simulator makes certain

assumption about the executable being debugged:

x The size of the application being debugged determines the maximum memory

location which can be accessed by the simulator.

x The simulator assumes that the accesses are made only to the fast local memory

(LMB).

When using the command info target, the number of cycles reported by the simulator

are under the assumptions that memory access are done only into local memory (LMB).

Any access to the peripherals results in the simulator indicating an error. This target does

not require xmd to be started up. This target should be used for basic verification of

functional correctness of programs which do not access any peripherals or OPB or external

memory.

Remote

Remote debugging is done through XMD. The XMD server program can be started on a

host computer with the Simulator target or with the Hardware target transparent to mb-

gdb. Both the Cycle-Accurate Instruction Set Simulator and the Hardware interface

provide powerful debugging tools for verifying a complete MicroBlaze system. mb-gdb

connects to xmd using the GDB Remote Protocol over TCP/IP socket connection.

Simulator Target

The XMD simulator is a Cycle-Accurate Instruction Set Simulator of the MicroBlaze system

which presents the simulated MicroBlaze system state to GDB.

Hardware Target

With the hardware target, XMD communicates with an xmdstub program running on a

hardware board through the serial cable or JTAG cable, and presents the running

MicroBlaze system state to GDB.

For more information about XMD refer to the XMD Chapter.