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Compiler User Guide
Types of data alignment
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| Home > Compiler Coding Practices > Types of data alignment | |||
All access to data in memory can be classified into the following categories:
Natural alignment, for example, on a word boundary at 0x1004. The ARM compiler normally aligns variables and pads structures so that these items are accessed efficiently using
LDRandSTRinstructions.Known but non-natural alignment, for example, a word at address 0x1001. This type of alignment commonly occurs when structures are packed to remove unnecessary padding. In C and C++, the
__packedqualifier or the#pragma pack(pragma is used to signify that a structure is packed.n)Unknown alignment, for example, a word at an arbitrary address. This type of alignment commonly occurs when defining a pointer that can point to a word at any address. In C and C++, the
__packedqualifier or the#pragma pack(pragma is used to signify that a pointer can access a word on a non-natural alignment boundary.n)
See also| Copyright © 2007-2008, 2011-2012 ARM. All rights reserved. | ARM DUI 0375D |
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