x86-64 FPSR Register

The bit settings of the x86-64 FPSR register are outlined in the following table.

Value	Bit Setting	Meaning
TOP=<i>	0x3800	Register <i> is top of FPU stack
B	0x8000	FPU busy
C0	0x0100	Condition bit 0
C1	0x0200	Condition bit 1
C2	0x0400	Condition bit 2
C3	0x4000	Condition bit 3
ES	0x0080	Exception summary status
SF	0x0040	Stack fault
EF=PE	0x0020	Precision exception
EF=UE	0x0010	Underflow exception
EF=OE	0x0008	Overflow exception
EF=ZE	0x0004	Zero divide exception
EF=DE	0x0002	Denormalized operand exception
EF=IE	0x0001	Invalid operation exception