Thursday, January 11, 2007

RVDS ARMulator and GNUARM-compiled binaries

I have started to use the ARMulator , which is also called the RealView Instruction Set Simulator (RVISS). I was interested to see if the binaries compiled using the GNUARM toolchain could work with the ARMulator. Specifically, I was hoping that the input/output (from printf or fgets, for example) could be done from within the RealView Debugger (RVD) session itself. To my surprise, the GNUARM-compiled binaries would not show printf output when ran using the RVD/ARMulator even though they worked just fine with GDB. I have customized my crt0.S, so that was the first place I looked. In addition, writing a simple code using printf and fgets and compiling it using GNUARM without using my custom crt0.S seemed to work. Lo and behold, after comparing my crt0.S and the default one within the GNUARM distribution, I found that I had failed to call initialise_monitor_handles in my crt0.S. Doing this after stack initialization and BSS clearing fixed the problem.

(Apparently, the problem above only appears in GNUARM toolchain from The toolchain from CodeSourcery does not exhibit this problem. In fact, the latter does not even have the initialise_monitor_handles function. Oh, well.)

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