I have a curious question for someone that may be familar with an IAR 8051 C compiler that dates back a few years. (Note I do not have that compiler and never used it).

I inherited a batch of code that I am porting to KEIL C51. The previous generation of this project was built with a Dallas 80C320 with external 128K byte FLASH and 32K byte SRAM. I am moving it to a new processor with internal 128K FLASH and 8K XRAM.

Within this project I have found source code for pointers to a bunch of buffers and variable tidbits that were located in the external SRAM. For reasons I do not understand these were hard coded with C code that looks like:

#define EGR_MSG_ID_LOC (*(unsigned char *) 0x017B02)
. . .
#define PLGR_POSITION_MSG 0xB0 /* block 5040 */
. . .

if (EGR_MSG_ID_LOC == PLGR_POSITION_MSG)
{
/* switch the buffer ... */
....
}

Can anyody help me to understand as to why thus code is written in such a bizzare way?

Michael Karas