ARM ARM7TDMI - Data Types

Programmer’s Model
2-6 Copyright © 2001, 2004 ARM Limited. All rights reserved. ARM DDI 0210C
2.4 Data types
The ARM7TDMI processor supports the following data types:
• words, 32-bit
• halfwords, 16-bit
• bytes, 8-bit.
You must align these as follows:
• word quantities must be aligned to four-byte boundaries
• halfword quantities must be aligned to two-byte boundaries
• byte quantities can be placed on any byte boundary.
Note
Memory systems are expected to support all data types. In particular, the system must
support subword writes without corrupting neighboring bytes in that word.