6.4. Data Type Conversion
The Cortex®-M processors support a number of instructions for converting data between different data types.
6.4.1. Conversion of Data Size
On compilers for ARM® architecture, different data types have different sizes. A number of commonly used data types and its corresponding sizes on ARM compilers are shown in the following table (Table 6.7).
Table 6.7
Size of commonly used data types in C language for ARM® architecture
| C data type | Number of bits |
| “char”, “unsigned char” | 8 |
| “enum” | 8/16/32 (Smallest is chosen) |
| “short”, “unsigned short” | 16 |
| “int”, “unsigned int” | 32 |
| “long”, “unsigned long” | 32 |
When converting a data value from one type to another type with a larger size, we need to sign extend or zero extend it. A number of instructions are ...
Get The Definitive Guide to ARM® Cortex®-M0 and Cortex-M0+ Processors, 2nd Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
