hello all, i dont know how to access DPTR and regisrers using C programming. kindly help me in this .
You will find header files in the folder INC which contains the definitions of all SFR's. To insert the header required for you controller, simply right click in the C file, a popup menu appears which gives you the option to include the header file for you specific controller. You ill find all SFR's defined in their conventional names and in capital letters e.g. the port 0 is defined as "P0" data pointer as "DPH" and "DPL" and so on.
As noted in your cross-post: http://www.8052.com/forum/read.phtml?id=69151 although it is possible to do this, it is almost certainly a very Bad Idea Why do you want to do this?
As your cross-post says that you've only just downloaded the Raisonance tools, and judging by the nature of the question, can we assume that you are new to 'C' on the 8051? If so, for the Keil tools, the first thing to do is to read the uVision Getting Started Guide, and work throught the example projects in it. You will also need to read the C51 Manual, to find learn about the language extensions that Keil have added to cope with the 8051-specifics (like SFRs, bit-addressable objects, XDATA, etc). These will give you a proper introduction to the tools and how to use them, and save you having to ask elementary questions here. No Doubt Raisonance have similar documents.