In the oregano 8051 architecture, at reset PC starts at address zero, can anybody tell me what to modify in the startup.a51 and init.a51 files, so that they correctly jump to address of main program, and also to make sure that these startup files themselves start at address zero. Thank you...
"the start address of main as 0x0400"
Why? What is your specific reason for needing main to start at that address?
"the address of external interrupt function(/INT1) as 0x0013"
Why? A properly defined interrupt function will automatically be located to the correct address - there is no need to do it manually.
"I have also included a assembly file, with start address as zero"
Again, Why?
Why not just leave that as the location for the standard startup file?
You can either work with the tools, or fight them.
okay, I get your point. I am not fighting the tool, its about more control over the tool, and specifically the startup codes that I am having difficulty with. I was trying to generate a executable code with the above configuration..... if I try to place my code in address range 0x0000-0x0003, it gives error, m51 file says that these address are absolute....
okay, I get your point.
Apparently no, you don't. You were asked three different "why?" questions, but haven't answered any of them. You just insist on doing the same things.
I am not fighting the tool,
Oh yes, you are.
its about more control over the tool,
Of course it is. The process of gaining control over the tools which you previously hadn't, is "fighting".
if I try to place my code in address range 0x0000-0x0003, it gives error,
Of course it does! That's the Reset Vector location. The default startup code has to use that to start the program. If you're going to trample on that location, you better know how to modify the startup code to work without it. Do you?
"its about more control over the tool"
And what is wrong with the way the tools do it? Why do you specifically want to override the way the tools work?
It really sounds like you need to spend some more time studying how the tools work before trying to override them...