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

Descriptions of extended keywordsSee also Calling convention, page 85.__data16SyntaxDescriptionFollows the generic syntax rules for memory type attributes that can be used on dataobjects, see Type attributes, page 189.The __data16 memory attribute explicitly places individual variables and constants indata16 memory, which is the entire 64 Kbytes of memory in the MSP430 architectureand the lower 64 Kbytes in the MSP430X architecture. You can also use the __data16attribute to create a pointer explicitly pointing to an object located in the data16 memory.Storage information ● Address range: 0–0xFFFF (64 Kbytes)● Maximum object size: 65535 bytes● Pointer size: 2 bytesExample __data16 int x;See also Memory types (MSP430X only), page 15.__data20SyntaxDescriptionFollows the generic syntax rules for memory type attributes that can be used on dataobjects, see Type attributes, page 189.The __data20 memory attribute explicitly places individual variables and constants indata20 memory, which is the entire 1 Mbyte of memory in the MSP430X architecture.You can also use the __data20 attribute to create a pointer explicitly pointing to anobject located in the data20 memory. The __data20 attribute cannot be used in theSmall data model.Storage information ● Address range: 0–0xFFFFF (1 Mbyte)● Maximum object size: 0xFFFFF bytes● Pointer size: 20 bits in register, 4 bytes in memoryExample __data20 int x;See also Memory types (MSP430X only), page 15.194MSP430 IAR C/C++ CompilerReference Guide