3.6.6 Floating-Point Status Register
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]: The status generated by executing a floating-point compare (FCPS/FCPQ) 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.
| 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. |