Flush-To-Zero Mode

These enable or disable the flushing of subnormals to zero. Note that enabling this isn't IEEE compliant.

Enabling FTZ:

VMRS r0, FPSCR
ORR r0, r0, #(1 << 24)
VMSR FPSCR, r0

Disabling FTZ

VMRS r0, FPSCR
BIC r0, r0, #(1 << 24)
VMSR FPSCR, r0