MSP430 IAR C/C++ Compiler reference guide - Rice University

Introduction to the runtime environmentThe runtime library is delivered both as prebuilt libraries and as source files, and youcan find them in the product subdirectories 430\lib and 430\src\lib, respectively.The runtime environment also consists of a part with specific support for the targetsystem, which includes:●Support for hardware features:● Direct access to low-level processor operations by means of intrinsic functions,such as functions for register handling●●Peripheral unit registers and interrupt definitions in include filesThe MSP430 hardware multiplier peripheral unit.● Runtime environment support, that is, startup and exit code and low-level interfaceto some library functions.● Special compiler support for some functions, for instance functions forfloating-point arithmetics.The runtime environment support as well as the size of the heaps must be tailored forthe specific hardware and application requirements.For further information about the library, see the chapter Library functions.LIBRARY SELECTIONTo configure the most code-efficient runtime environment, you must determine yourapplication and hardware requirements. The more functionality you need, the largeryour code will become.IAR Embedded Workbench comes with a set of prebuilt runtime libraries. To get therequired runtime environment, you can customize it by:●Setting library options, for example, for choosing scanf input and printf outputformatters, and for specifying the size of the stack and the heap● Overriding certain library functions, for example cstartup.s43, with your owncustomized versions● Choosing the level of support for certain standard library functionality, for example,locale, file descriptors, and multibyte characters, by choosing a libraryconfiguration: normal or full.In addition, you can also make your own library configuration, but that requires that yourebuild the library. This allows you to get full control of the runtime environment.Note: Your application project must be able to locate the library, include files, and thelibrary configuration file.46MSP430 IAR C/C++ CompilerReference Guide