RealView Compilation Tools Compiler Reference Guide - ARM ...

Compiler Command-line Options
4 Treats accesses through pointers as having an alignment of at most four,
that is, at most word aligned.
8 Accesses through pointers have normal alignment, that is, at most
doubleword aligned.
Usage
This option can help you port source code that has been written for architectures without
alignment requirements. You can achieve finer control of access to unaligned data, with
less impact on the quality of generated code, using the __packed qualifier.
Restrictions
De-aligning pointers might increase the code size, even on CPUs with unaligned access
support. This is because only a subset of the load and store instructions benefit from
unaligned access support. The compiler is unable to use multiple-word transfers or
coprocessor-memory transfers, including hardware floating-point loads and stores,
directly on unaligned memory objects.
Note
• Code size might increase significantly when compiling for CPUs without
hardware support for unaligned access, for example, pre-v6 architectures.
• This option does not affect the placement of objects in memory, nor the layout and
padding of structures.
See also
• __packed on page 4-11
• Aligning data on page 4-24 in the Compiler User Guide.
2.1.98 --[no_]project=filename
The option --project=filename instructs the compiler to load the project template file
specified by filename.
Note
To use filename as a default project file, set the RVDS_PROJECT environment variable to
filename.
The option --no_project prevents the default project template file specified by the
environment variable RVDS_PROJECT from being used.
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