3.1 About floating-point support

The ARM® floating-point environment is an implementation of the IEEE 754-1985 standard for binary floating-point arithmetic.

Note:

In ARMv8, floating-point hardware is integral to the architecture. Software floating-point is supported for AArch32 state, but is not supported for AArch64 state.

An ARM system might have:

  • A VFP coprocessor.
  • No floating-point hardware.

If you compile for a system with a hardware VFP coprocessor, the ARM compiler makes use of it. If you compile for a system without a coprocessor, the compiler implements the computations in software. For example, the compiler option -mfloat-abi=hard selects a hardware VFP coprocessor and the option -mfloat-abi=soft specifies that arithmetic operations are to be performed in software, without the use of any coprocessor instructions.

Note:

In ARM Compiler 6, there is no command-line option to exclude both hardware and software floating-point computations. If the compiler encounters floating-point types in the source code, it will use software-based floating-point library functions.
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