 in computing, peek is a basic programming language extension used for reading the contents of a memory cell at a specified address. the corresponding command to set the contents of a memory cell is poke. ==statement syntax== the peek function and poke command are usually invoked as follows, either in direct mode (entered and executed at the basic prompt) or in indirect mode (as part of a program): integer_variable = peek(address) poke address, value the address and value parameters may contain complex expressions, as long as the evaluated expressions correspond to valid memory addresses or values, respectively. a valid address in this context is an address within the computer's address space, while a valid value is (typically) an unsigned value between zero and the maximum unsigned number that the minimum addressable unit (memory cell) may hold. ==memory cells and hardware registers== the address locations that are poked or peeked at may refer either to ordinary memory cells or to memory-mapped hardware registers of i/o units or support chips such as sound chips and video graphics chips, or even to memory-mapped registers of the cpu itself (which makes software implementations of powerful machine code monitors and debugging/simulation tools possible). as an example of a poke-driven support chip control scheme, the following poke command is directed at a specific register of the commodore 64's built-in vic-ii graphics chip, which will make the screen border turn black: poke 53280, 0 a similar example from the atari 8-bit family told the antic display driver to turn all text upside-down: poke 755,4 the difference between machines, and the importance and utility of the hard-wired memory locations, meant that "memory maps" of various machines were important documents. a canonical example is mapping the atari, which started at location zero and mapped out the entire 64 kb memory of the atari systems location by location. pre and non-pc computers usually differ in the memory address areas designated for user programs, user data, operating system code and data, and memory-mapped hardware units. for these reasons, peek functions and poke commands are inherently non-portable, meaning that a given sequence of those statements will almost certainly not work on any system other th
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