3.6.6 Floating-Point Status Register⁽¹⁾

Note:

The FSR register is not memory mapped.

Note: Dynamic floating-point exception status, FSR [6:0]: Dynamic status bits are updated based on the results from each instruction Functional Block and will be updated after execution of each instruction.

Sticky floating-point exception status, FSR [14:8]: Sticky status bits can be set based on the results from each instruction Functional Block but cannot be cleared by hardware (other than at device Reset), and therefore represent a history of status since the last time the sticky bits were cleared. The FSR bits can be cleared through software.

Floating point compare status, FSR [19:16]: Status generated by executing a floating-point compare (FCPQ/FCPS) instruction. Used individually or combined to generate the floating-point branch conditions used by the CPU CBRAn instructions.

Floating-point test status, FSR [27:24]: Floating-point datum characteristic status generated by executing the floating-point test (FTST) instruction.

Table 3-42. Register Bit Attribute Legend
Symbol	Description	Symbol	Description	Symbol	Description
R	Readable bit	HC	Cleared by Hardware	(Gray cell)	Unimplemented
W	Writable bit	HS	Set by Hardware	X	Bit is unknown at Reset
C	Write to clear	S	Software settable bit	x	Channel number

Name:

FSR


Bit	31	30	29	28	27	26	25	24
				SUB	INF	FN	FZ	FNAN
Access				R/W	R/W	R/W	R/W	R/W
Reset				0	0	0	0	0


Bit	23	22	21	20	19	18	17	16
					GT	LT	EQ	UN
Access					R/W	R/W	R/W	R/W
Reset					0	0	0	0


Bit	15	14	13	12	11	10	9	8
		SUBOS	HUGIS	INXS	UDFS	OVFS	DIV0S	INVALS
Access		R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset		0	0	0	0	0	0	0


Bit	7	6	5	4	3	2	1	0
		SUBO	HUGI	INX	UDF	OVF	DIV0	INVAL
Access		R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset		0	0	0	0	0	0	0

Bit 28 – SUB (FTST) Subnormal Status bit

Value	Description
1	Operand is subnormal
0	Operand result is not subnormal

Bit 27 – INF (FTST) Infinite Status bit

Value	Description
1	Operand is infinite
0	Operand is not infinite

Bit 26 – FN (FTST) Negative Status bit

Value	Description
1	Operand is negative
0	Operand is not negative

Bit 25 – FZ (FTST) Zero Status bit

Value	Description
1	Operand is zero
0	Operand is not zero

Bit 24 – FNAN (FTST) Not a Number Status bit

Value	Description
1	Operand is a NaN (qNaN or sNaN) value
0	Operand is not a NaN value

Bit 19 – GT (FCPS/FCPQ) Greater Than Status bit

Value	Description
1	Minuend is greater than the subtrahend (Fb > Fs)
0	Minuend is not greater than the subtrahend (Fb ≤ Fs)

Bit 18 – LT (FCPS/FCPQ) Less Than Status bit

Value	Description
1	Minuend is less than the subtrahend (Fb < Fs)
0	Minuend is not less than the subtrahend (Fb ≥ Fs)

Bit 17 – EQ (FCPS/FCPQ) Equal Status bit

Value	Description
1	Minuend is equal to the subtrahend (Fb = Fs)
0	Minuend is not equal to the subtrahend (Fb != Fs)

Bit 16 – UN (FCPS/FCPQ) Unordered Status bit

Value	Description
1	Either or both operands are NaN values
0	Neither operands are NaN values

Bit 14 – SUBOS Sticky Subnormal Operand Exception Flag bit

Value	Description
1	Subnormal Operand exception has just occurred, or at some time in the past
0	Subnormal Operand exception has not occurred

Bit 13 – HUGIS Sticky Huge Integer Exception Flag bit

Value	Description
1	Huge Integer exception has just occurred, or at some time in the past
0	Huge Integer exception has not occurred

Bit 12 – INXS Sticky Inexact Exception Flag bit

Value	Description
1	Inexact exception has just occurred, or at some time in the past
0	Inexact exception has not occurred

Bit 11 – UDFS Sticky Underflow Exception Flag bit

Value	Description
1	Underflow exception has just occurred, or at some time in the past
0	Underflow exception has not occurred

Bit 10 – OVFS Sticky Overflow Exception Flag bit

Value	Description
1	Overflow exception has just occurred, or at some time in the past
0	Overflow exception has not occurred

Bit 9 – DIV0S Sticky Divide by Zero Exception Flag bit

Value	Description
1	Divide by Zero exception has just occurred, or at some time in the past
0	Divide by Zero exception has not occurred

Bit 8 – INVALS Sticky Invalid Exception Flag bit

Value	Description
1	Invalid exception has just occurred, or at some time in the past
0	Invalid exception has not occurred

Bit 6 – SUBO Subnormal Operand Exception Flag bit

Value	Description
1	Subnormal Operand exception has occurred
0	Subnormal Operand exception has not occurred

Bit 5 – HUGI Huge Integer Exception Flag bit

Value	Description
1	Huge Integer exception has occurred
0	Huge Integer exception has not occurred

Bit 4 – INX Inexact Exception Flag bit

Value	Description
1	Inexact exception has occurred
0	Inexact exception has not occurred

Bit 3 – UDF Underflow Exception Flag bit

Value	Description
1	Underflow exception has occurred
0	Underflow exception has not occurred

Bit 2 – OVF Overflow Exception Flag bit

Value	Description
1	Overflow exception has occurred
0	Overflow exception has not occurred

Bit 1 – DIV0 Divide by Zero Exception Flag bit

Value	Description
1	Divide by Zero exception has occurred
0	Divide by Zero exception has not occurred

Bit 0 – INVAL Invalid Exception Flag bit

Value	Description
1	Invalid exception has occurred
0	Invalid exception has not occurred

3.6.6 Floating-Point Status Register(1)