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RealView Compiler User's Guide
Preface Introduction Getting started with the ARM Compiler Compiler Features Coding Practices Optimizing code
Optimizing for size versus speed Optimization levels and the debug view Selecting the target device Optimizing loops Using volatile Code metrics Measuring code and data sizes Measuring stack use Reducing debug information in objects and librarie Functions Minimizing parameter passing overhead __value_in_regs __pure Placing ARM function qualifiers Inlining How the compiler decides to inline When is it practical for the compiler to inline? Managing inlining Inlining functions across multiple files Debugging data and the --[no]_inline keyword Marking functions as static Setting breakpoints on inlined functions in ROM im Aligning data About data alignment The __packed qualifier and unaligned accesses to d __packed structures versus individually __packed f Using floating-point arithmetic Support for floating-point operations VFP architectures The --fpu option Floating-point linkage The --fpmode option Using the --fpu option VFP support Trapping and identifying division-by-zero errors Integer division (Software) Floating point division Support for ARM architecture v6 Instruction generation Alignment support Endian support Diagnostic Messages Using the Inline and Embedded Assemblers SemihostingThe --fpmode option
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| Home > Coding Practices > Using floating-point arithmetic > The --fpmode option | |||
You can specify the floating-point conformance and floating-point optimization using the --fpmode option. Different libraries are selected depending on the model chosen.
Table 4.12. Floating‑point models supported in RVCT
| Option | Description |
|---|---|
| All facilities, operations and representations guaranteed by the IEEE standard are available in single and double precision. Modes of operation can be selected dynamically at run-time. |
| IEEE standard with round-to-nearest and no inexact exceptions. |
| IEEE standard with round-to-nearest and no exceptions. This mode is compatible with the Java floating-point arithmetic model. |
| IEEE finite values with denormals flushed to zero, round-to-nearest and no exceptions. This is the default option and is C and C++ compatible. |
| Perform more aggressive floating-point optimizations that might cause a small loss of accuracy to provide a significant performance increase. This option results in behavior that is not fully compliant with the ISO C and ISO C++ standards. However, numerically robust floating-point programs behave correctly. |
Note
Initialization code might be required to enable the VFP. See VFP support for more information.
For more information on specifying floating-point conformance, see:
‑‑fpmode=model in the Compiler Reference Guide.
| Copyright © 2007 ARM Limited. All rights reserved. | ARM DUI 0375A |
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