i want to multiply 24bit value which i get from spi ,i stored it in an array of 3byte & i want to multiply with a constant of 8bit,the result i get which is a 32bit has to be divided with a constant of 32bit i want a c code for this procedure so pls help me
Look in the C51 Manual to see what data types are available:
http://www.keil.com/support/man/docs/c51/c51_ap_datastorage.htm
There isn't a 24-bit type, so you will just have to use the next size up, and have a few spares!