 CARM User's Guide Discontinued | |
| Home Products Events Support | |
Technical Support
On-Line Manuals
CARM User's Guide
CARM Introduction Compiling Programs Language Extensions Preprocessor Advanced Programming Customization Files
Startup Code Basic I/O Memory Allocation Interfacing C to Assembler Function Parameters Function Return Values Using the SRC Directive Register Usage Example Routines ARM Code Example Thumb Code Example Data Storage Formats Byte Order Byte Alignment Integer Scalars 1-Byte Scalars 2-Byte Scalars 4-Byte Scalars 8-Byte Scalars float Scalars float Format float Errors double Scalars double Format double Errors Pointers Bit Fields Absolute Memory Access The __at Keyword Linker Location Controls Error Messages Library Reference AppendixData Storage Formats
The CARM C Compiler offers a number of basic data types to use in your C programs. The following table lists these data types along with their size requirements and value ranges.
| Data Type | Bits | Bytes | Alignment | Value Range |
|---|---|---|---|---|
| signed char1 | 8 | 1 | 1 | -128 to +127 |
| unsigned char | 8 | 1 | 1 | 0 to 255 |
| signed short1 | 16 | 2 | 2 | -32768 to +32767 |
| unsigned short | 16 | 2 | 2 | 0 to 65535 |
| enum2 | 32 | 4 | 4 | -2147483648 to +2147483647 |
| signed int1 | 32 | 4 | 4 | -2147483648 to +2147483647 |
| unsigned int | 32 | 4 | 4 | 0 to 4294967295 |
| signed long1 | 32 | 4 | 4 | -2147483648 to +2147483647 |
| unsigned long | 32 | 4 | 4 | 0 to 4294967295 |
| signed long long1 | 64 | 8 | 4 | -263 to +263-1 |
| unsigned long long | 64 | 8 | 4 | 0 to 264-1 |
| float | 32 | 4 | 4 | ±1.175494E-38 to ±3.402823E+38 |
| double | 64 | 8 | 4 | ±1.7-308 to ±1.7E+308 |
| pointer | 32 | 4 | 4 | 32-bit Address |
Note
- Signed types are stored in two's complement.
- The enum type is stored using the shortest signed or unsigned integer type required to contain its value.
Other data types, like structures and unions, may contain scalars from this table.
| Contact Site Map Press Privacy | Copyright © 2008 Keil™, An ARM® Company. All rights reserved. |
