I want to write IAP boot loader code with single flash memory (with out having facility of Read-while-write).

I am using M16C processor and Flash (with out boot block)
Unlike 8051 Memory Flash and RAM is interfaced in same way
with separate 8 data lines and address line (no multiplex).

My steps to boot loader (c code ) are as follow
1.My code will start executing from reset interrupt location in flash.
2.program identifies weather firmware upgrade is required of not
3.If it is required the program will copy boot loader into RAM from flash. (as I don’t have separate boot block in flash)
4.Will jump to RAM memory and will execute program from RAM .
5.Through serial port program will receive new file for application firmware and will write flash.
6.After complete write will jump to ROM for application execution.


My problem is if I will execute from RAM it will jump to ROM location for different function calls like WriteFlash( ) EraseFlash( ) while executing as the code for boot loader is linked according to Flash memory while linking. How should I write it in c language?


This method that I am using may not be standard method to write IAP but If any one can suggest it will be help full. I searched in google but most of them using separate memory for opcode read and new firmware write.

Regards,
Vikrant