Library Reference

The C51 run-time library provides more than 100 predefined functions and macros you may use in your 8051 C programs. The library makes embedded software development easier by providing routines that perform common programming tasks such as string and buffer manipulation, data conversion, and floating-point math operations.

The routines in this library conform to the ANSI C Standard. However, some functions differ slightly in order to take advantage of the features of the 8051 architecture. For example, the isdigit function returns a bit value as opposed to an int. Where possible, function return types and argument types are adjusted to use the smallest data type possible. In addition, unsigned data types are favored over signed types. These changes to the standard library provide a maximum of performance while reducing program size.

All routines in this library are implemented to be independent of register bank.