VFP is a floating-point architecture which can provide both single and double precision operations. Many operations may also take place in scalar form or in vector form. At the time of writing three versions of the architecture have been implemented:

In addition particular implementations may provide implementation-specific functionality. For example, the VFP coprocessor hardware can include extra registers describing an exceptional condition. These registers are not described in the VFP architecture, yet the operating system needs to know about them when handling the exception, and sometimes when saving VFP context.

This extra functionality is known as the subarchitecture of the implementation. This must be relied upon only by system software, and only as described in this application note. Functions that depend on subarchitecture functionality should also be separated from the main body of the system software, so that it is easy to change to another VFP implementation. All other software must only rely upon the general architectural definition of the VFP architecture contained in the ARM Architecture Reference Manual.