What is the meaning of 0x10000000 in embedded C programming using LPC2129?

Answer 1

The meaning is entirely dependent upon the data the value actually represents. As an unsigned integer, 0x10000000 represents the value 128. As a signed integer it would represent -127 on a ones-complement system and -128 on a twos-complement system. Regardless of its value, the meaning depends on what that value is supposed to represent. It could be an index into an array, a character code, a memory address, an instruction, or indeed anything the programmer desires it to mean. Ultimately it is just a binary representation for some piece of information that is stored digitally. We (humans) can interpret it as a number, but to the computer it is nothing more than a binary code. What that code represents is entirely open to interpretation.