
CHAPTER 2 REGISTER SET
10
Bit Position
Flag
Function
31 - 8
RFU
Reserved for Future Use
Reserved field (fixed to 0).
7
NP
NMI Pending
Indicates that NMI processing is in progress. This flag is set when NMI is granted.
The NMI request is then masked, and multiple interrupts are disabled.
NP = 0: NMI processing is not in progress
NP = 1: NMI processing is in progress
6
EP
Exception Pending
Indicates that exception processing is in progress. This flag is set when an excep-
tion occurs.
EP = 0: Exception processing is not in progress
EP = 1: Exception processing is in progress
5
ID
Interrupt Disable
Indicates whether external interrupt request can be accepted.
ID = 0: Interrupt can be accepted
ID = 1: Interrupt cannot be accepted
4
SAT
Note
Saturated Math Result
Indicates that an overflow has occurred in a saturate operation and the result is
saturated. This is a cumulative flag. Once the result is saturated, the flag is set to
1 and is not reset to 0 even if the next result does not saturate. To reset this flag,
load data to PSW.
This flag is neither set nor reset by general arithmetic operation instruction.
SAT = 0: Not saturated
SAT = 1: Saturated
3
CY
Carry
Indicates whether carry or borrow occurred as a result of the operation.
CY = 0: Carry or borrow did not occur
CY = 1: Carry or borrow occurred
2
OV
Note
Overflow
Indicates whether overflow occurred as a result of the operation.
OV = 0: Overflow did not occur
OV = 1: Overflow occurred
1
S
Note
Sign
Indicates whether the result of the operation is negative
S = 0: Result is positive or zero
S = 1: Result is negative
0
Z
Zero
Indicates whether the result of the operation is zero
Z = 0: Result is not zero
Z = 1: Result is zero
Note
In the case of saturate instructions, the SAT, S, and OV flags will be set accordingly by the result of the
operation as shown in the table below. Note that the SAT flag is set to 1 only when the OV flag has been
set due to an overflow condition caused by a saturate instruction.
Status of Operation Result
SAT-S-OV
Result of Saturation Processing
Maximum positive value is
exceeded
1 0 1
7FFFFFFFH
Maximum negative value
is exceeded
1 1 1
80000000H
Others
0
×
0
Operation result