To context switch VFP state you must save and restore the main VFP register bank using FLDMX and FSTMX instructions. The FPSCR must also be preserved.

If the EX bit is set in the FPEXC register, then there is additional state describing a pending exception that must also be saved. The subarchitecture support library provides functions for this. These are described in Section 7.6.2.

Context switching of VFP state can be reduced by only switching when an application uses the VFP. You can achieve this by disabling the VFP in ARM context switch code, (by clearing the EN bit in the FPEXC register), and then only switching VFP registers when the VFP Undef handler is entered, (as the result of an attempt to use the VFP).