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Data Shift Instructions Section 3-8
Description NSRL(583) shifts D and D+1 (the shift words) by the specified number of
binary bits (specified in C) to the right (from the leftmost bit to the rightmost
bit). Either zeros or the value of the rightmost bit will be placed into the speci-
fied number of bits of the shift word starting from the rightmost bit.
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 or 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 +1 is 00000000 hex, the Equals Flag
will turn ON.
If as a result of the shift the contents of the leftmost bit of D +1 is 1, the Nega-
tive Flag will turn ON.
Indirect DM addresses
in binary
@ D0 to @ D32767
Indirect DM addresses
in BCD
*D0 to *D32767
Constants --- Specified values only
Data Registers --- DR0 to DR15
Index Registers ---
Indirect addressing
using Index Registers
,IR0 to ,IR15
-2048 to +2047 ,IR0 to -2048 to +2047 ,IR15
DR0 to DR15, IR0 to IR15
,IR0+(++) to ,IR15+(++)
,
–(– –)IR0 to, –(– –)IR15
Area D C
Shift n-bits
Los
Contents of "a" or
"0" shifted in
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.
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