http://www.cnblogs.com/processakai/archive/2011/06/24/2089343.html
Using the __at macro that is defined in the header file absacc.h allows you to locate variables to absolute addresses as shown below:
C Example:#i nclude <absacc.h> const char MyText[] __at (0x1F00) = "TEXT AT ADDRESS 0x1F00"; int x __at (0x40003000); // variable at address 0x40003000