3.6. Working with the Target

GCC-1750 also supports debugging on the target computer. Before you can do this, you must connect the target board to the host computer using two serial cables that include a null modem. One cable connects the board's serial connector A to the host, and is used to down-load the monitor and for application program input and output. The other cable connects to the board's serial connector B, and is used by the debugger to load programs, and to perform debugging operations.

3.6.1. How to Down-load the Debug Monitor

Before you can use the debugger to down-load and debug programs running on the target, you must down-load the GCC-1750 debug monitor. This is a small program that resides in the upper part of RAM, and communicates with the M1750 debugger over the serial interface B. You will find example source code on the CD-ROM in directory src/runtimes/monitor/.

Note: The debug monitor is supplied as an example program. It must be customized for your target computer. This may take much longer than you think.

The following example shows the Ackermann benchmark running under the control of the debugger. You should substitute your serial device name for ttyS0.

$ m1750-coff-gdb ackermann
XGC Debugger Version 4.17.gnat.3.11 for m1750-coff
Copyright (c) 1998 Free Software Foundation, Inc...
(gdb) set remote speed 19200
(gdb) tar rem /dev/ttyS0
Remote debugging using /dev/ttyS0
0x21f965c in ?? ()
(gdb) load
Loading section .text, size 0x1948 lma 0x0
Loading section .rdata, size 0x3d8 lma 0x1948
Loading section .data, size 0x50 lma 0x1d20
Start address 0x110
Transfer rate: 6698 bits/sec.
(gdb) run
Starting program: /hdb3/xgc/benchmarks/ackermann
,.,. ackermann GTS Version 0.1
---- ackermann Function call benchmark, A (3, 6).
   - ackermann time taken = 1.130e+00 Seconds.
**** ackermann  PASSED ============================.

Program exited normally.
(gdb) quit