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I have written a MBR + Kernel that runs in a Virtual VM Ware. The Master Boot Record loads the Kernel, sets Protected Mode and then jumps into the kernel. The kernel consists of an Assembler part and an C part. The Assembler-code just starts the main()-function in C. This works great, but I have a problem in the C-file:

All references to constant data are not working. When I call the printf-function of my kernel:
e.g: printf("bla");

The "bla" is not displayed on the screen, but the function is 100% working. The function sets the local video memory. Putting a simple char in the video memory works great, but strings and constants are messed up.

I think it has to do with my GDT.

I am happy about every suggestion or solution.

I've attached the whole project as an .zip file.

Thank you,
Thomas Krause

seems like you're missing the "rodata" section ... (hmm. can't remember if DjGPP uses this)

btw, it's likely that there's a problem with the 'load address'. MBR calls the kernel with SYS:90000 and the linker has targetted the kernel at SYS:100 ...

Thank you, that was the problem. I changed the linker parameters to set the Text-Section to 9000 (Ttext=0x9000) and now it is working.

Thomas Krause