We have decided to use the Cypress FX2 which has code examples for Keil. While I have years of experience with IAR and Ti Code Composer I'm new to Keil and have not seen _AT_ used as follows:
EXTERN xdata volatile BYTE REVID _AT_ 0xE60A; /* Chip Revision */
A pointer to the right Keil user guide / syntax for _AT_ or a ANSI C equivalent would be greatly appreciated.