How to pass values in perticular register?
I am using 89v51rd2 & want to pass values in R1 and DPTR for IAP.
When you write in a High-Level Language (HLL) - any HLL, including 'C' - the whole point is that you delegate details like specific register choice to the compiler.
Therefore, if specific register choice really is important to you, you must write in Assembler.
C51's calling convention (including register usage) is clearly documented here: http://www.keil.com/support/man/docs/c51/c51_ap_funcparam.htm http://www.keil.com/support/man/docs/c51/c51_ap_parampassreg.htm
"pass values in R1 and DPTR for IAP"
You will need, at least, to write an "interface" function in assembler.
You will need to study: http://www.keil.com/support/man/docs/c51/c51_ap_ctoasm.htm
Thank you
Done