IBM XT 5160

FCLEX = Clear Exceptions
I escape 011 I 11100010
FSTENV = Store Environment
escape 001
mod110 rIm
disp-low disp-high
FLDENV = Load Environment
escape 001
mod100 rIm
disp-low
disp-high
FSAVE = Save State
escape 101
mod110 rIm
disp-low disp-high
FRSTOR = Restore State
escape 101
mod100 rIm
disp-low
disp-high
FINCSTP = Increment Stack Pointer
escape 001 11110111
FDECSTP = Decrement Stack Pointer
I escape 001 11110110
FFREE = Free ST(i)
I escape 001 I 11000ST(i)
FNOP = No Operation
I escape 001 I 11010000
FWAIT = CPU Wait for NDP
I 10011011
6-30 Instruction Set