i~. MCS@-51PROGRAMMER’SGUIDE AND INSTRUCTIONSET
DEC direct
Bytes:
Cycles:
Encoding:
Operation:
DEC @Ri
Bytes:
Cycles:
Encoding:
Operation:
DIV AB
2
1
0001 0101
I
directaddress
DEC
(direct)- (direct) – 1
1
1
10001 I Ollil
DEC
(w)) -((N)) – I
Function:
Divide
Description:
DIV AB divideathe unsignedeight-bitintegerin the Accumulatorby the unsignedeight-bit
integer in register B. The Accumulatorreceivesthe integerpart of the quotient;register B
receivesthe integerremainder.The carry snd OVtlagswillbe cleared.
Exception: ifB had originallycontainedOOH,the valuesreturned in the Accumulatorand B-
register willbe undefinedand the overflowflag willbe set. The carry tlag is cleared in any
case.
Example: The Accumulatorcontains251(OFBHor 11111011B)andBcontains 18(12Hor OOO1OO1OB).
The instruction,
DIV AB
willleave 13in the Accumulator(ODHor OOOO11O1B)and the value 17(lIH or OOO1OOO1B)
in B, since251 = (13X 18) + 17.Carry and OVwillboth be cleared.
Bytes: 1
Cycles: 4
Enooding:
I
1000 0100
Operation:
DIV
(A)15.8
~)74 - (A)/@t)
2-42
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