CHAPTER 6 DETAILED RULES FOR EXECUTION INSTRUCTIONS
6.28 DEC (DECrement Byte Data of General-purpose Register)
Decrement byte data of Ri by one.
■DEC (DECrement Byte Data of
Operation
(Ri) ← (Ri) - 1 (byte subtract)
Assembler format
DEC Ri
Condition code (CCR)
N | Z | V | C |
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+ | + | + | - |
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+: Changed by executing instruction
N:Set to 1 if the MSB is 1 as the result of operation and set to 0 in other cases.
Z:Set to 1 if the result of operation is 00H and set to 0 in other cases.
V:Set to 1 if an overflow occurs as the result of operation and set to 0 in other cases.
C:Not changed
Number of execution cycles: 3
Byte count: 1
OP code: D8 to DF
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