162
5-14-2 REVERSIBLE SHIFT REGISTER: SFTR(051)
Variations
j SFTR(051)
(051)
SFTR C St E
Operand Data AreasLadder Symbol
C: Control word CIO, G, A, DM, DR, IR
E: End word CIO, G, A, DM
St: Starting word CIO, G, A, DM
SFTR(051) is used to create a single- or multiple-word shift register that can shift
data to either the right or the left. To create a single-word register, designate the
same word for St and E. The control word provides the shift direction, the status
to be put into the register, the shift pulse, and the reset input. The control word is
allocated as follows:
15 14 13 12 Not used.
Shift direction
1 (ON): Left
0 (OFF): Right
Status to input into register
Shift pulse bit
Reset
The data in the shift register will be shifted one bit in the direction indicated by
bit 12, shifting one bit out to CY and the status of bit 13 into the other end when-
ever SFTR(051) is executed with an ON execution condition as long as the reset
bit is OFF and as long as bit 14 is ON. If SFTR(051) is executed with an OFF
execution condition or if SFTR(051) is executed with bit 14 OFF, the shift register
will remain unchanged. If SFTR(051) is executed with an ON execution condi-
tion and the reset bit (bit 15) is OFF, the entire shift register and CY will be set to
zero.
St must be less than or equal to E, and St and E must be in the same data area.
Note Refer to page 115 for general precautions on operand data areas.
Flags ER (A50003): Content of a *DM word is not BCD when set for BCD.
St and E are not in the same data area or St is greater than
E.
CY (A50004): Receives the status of bit 00 of St or bit 15 of E, depending
on the shift direction.
Description
Precautions
Shift Instructions Section 5-14
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