Change execution address of binary file

Thanks for your response, Sandy!

I guess my question wasn't clear enough. The binary currently loads at the same addresses (&H8800 - &HC819), but it requires a basic file to load it and then execute the commands 'defusr=&HC800:a=usr(0)'. Maybe my assumption is wrong, but I thought that if I could set the execution address of the binary file to &HC800, then the basic file could be replaced by executing 'bload"filename",r'.

Ah, sorry for the misunderstanding

Then yes, what you are doing with the bsave command should work perfectly fine?

Some speculation of what could be going wrong:

• Are you sure you can safely use memory up to &HC819?
• Pure speculation from my side: I am not sure what kind of guarantee MSX Basic gives in terms of context when calling into assembly code. Strictly speaking, calling if from Basic using defusr means the assembly is called with a fully initialized (and running) Basic interpreter. Whereas using bload could just mean: load it in memory and immediately start running it, and only once we get back to the Basic interpreter will we do some cleanup?

Maybe first check that your .BIN header is actually correct? The first 7 bytes of the file should look like what is documented here: MSX Basic Binary Files

The bsave command turned out to work as expected after all. My problems seems to be caused by Disk Manager. In order to save files from the BlueMsx emulator, I have to write to a .dsk image, as the Windows file system is not supported for writing. But apparently files can become corrupted either in the .dsk image after importing them with Disk Manager or when extracting them to the Windows file system ('bad file mode' error when loading with bload). But I guess that is a completely new topic.
Thanks for your help, everyone!

You can use any hex editor on any modern operating system or on MSX itself.

If you follow Sandy Brand’s link you can see the execution address is encoded as a little-endian word in byte 5-6 of the BIN file.