CHAPTER 3 CPU FUNCTIONS
(2/2)
Note During saturated operation, the saturated operation results are determined by the contents of the OV
flag and S flag. The SAT flag is set to 1 only when the OV flag is set to 1 during saturated operation.
Operation result status
Flag status
OV
Saturated
operation result
SAT
S
Maximum positive value exceeded
Maximum negative value exceeded
Positive (maximum value not exceeded)
Negative (maximum value not exceeded)
1
1
1
1
0
0
1
0
1
7FFFFFFFH
80000000H
Holds value
Actual operation
result
before operation
(5) CALLT execution status saving registers (CTPC, CTPSW)
There are two CALLT execution status saving registers, CTPC and CTPSW.
When the CALLT instruction is executed, the contents of the program counter (PC) are saved to CTPC, and
the program status word (PSW) contents are saved to CTPSW.
The contents saved to CTPC consist of the address of the next instruction after the CALLT instruction.
The current PSW contents are saved to CTPSW.
Bits 31 to 26 CTPC and bits 31 to 8 of CTPSW are reserved (fixed to 0) for future function expansion.
31
2625
0
0
After reset
0xxxxxxxH
CTPC
0 0 0 0 0 0
(PC contents)
(x: Undefined)
31
8 7
After reset
000000xxH
CTPSW
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
(PSW contents)
(x: Undefined)
User’s Manual U15862EJ3V0UD
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NEC [ NEC ]
