402
Data Shift Instructions Section 3-9
Flags
Precautions For any bits which are shifted outside the specified word, the contents of the
last bit is shifted to the Carry Flag (CY), and all other data is lost.
When the number of bits to shift (specified in C) is “0,” the data will not be
shifted. The appropriate flags will turn ON and OFF, however, according to
data in the specified word.
When the contents of the control word C are out of range, an error will be gen-
erated and the Error Flag will turn ON.
If as a result of the shift the contents of D is 0000, the Equals Flag will turn
ON.
If as a result of the shift the contents of the leftmost bit of D, D +1 is 1, the
Negative Flag will turn ON.
Examples When CIO 000000 is ON, CIO 0100 and CIO 0101 will be shifted to the left
(from the rightmost bit to the leftmost bit) by 10 bits. The number of bits to shift
is specified in bits 0 to 7 of word CIO 0300 (control data). The contents of bit 0
of CIO 0100 is copied into bits from which data was shifted and the contents
of the rightmost bit which was shifted out of range is shifted into the Carry
Flag (CY). All other data is lost.
Name Label Operation
Error Flag ER ON when the control word C (the number of bits to shift) is
not within range.
OFF in all other cases.
Equals Flag = ON when the shift result is 0.
OFF in all other cases.
Carry Flag CY ON when 1 is shifted into the Carry Flag (CY).
OFF in all other cases.
Negative Flag N ON when the leftmost bit is 1 as a result of the shift.
OFF in all other cases.
15 8 011 37 412
C
080A
No. of bits to shift: 10 bits (0A Hex)
Always 0.
Data shifted into register
8 Hex: Contents of right-
most bit shifted in
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