hi, i'm a beginner i need program which multiply 2 real inputs , i want to know: how can i declare real variables on C ,also i can't deal with 8-bit registers R0--R7. in ASM language Mov R0,#10 i need to convert this code to C thnx;
i need to store data in these register
No, you quite certainly don't. R0 to R8 are no place to store something. Not in the middle of C code, anyway, because the compiled code needs those registers for itself.
You need to stop running head-first into the wall and go back to the chapter "What's a door, and why might I find it useful?"