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Data Shift Instructions Section 3-9
Description ROLL(572) shifts all bits of Wd and Wd +1 including the Carry Flag (CY) to
the left (from rightmost bit to leftmost bit).
Flags
Precautions When ROLL(572) is executed, the Error Flag will turn OFF.
If as a result of the shift the contents of Wd and Wd +1 are zero, the Equals
Flag will turn ON.
If as a result of the shift the contents of the leftmost bit of Wd + 1 is 1, the Neg-
ative Flag will turn ON.
Note It is possible to set the Carry Flag contents to 1 or 0 immediately before exe-
cuting this instruction, by using the Set Carry (STC(040)) or Clear Carry
(CLC(041)) instructions.
Examples When CIO 000000 is ON, word CIO 0100, CIO 0101 and the Carry Flag (CY)
will shift one bit to the left. The contents of CIO 010015 will be shifted to the
Carry Flag (CY) and the Carry Flag contents will be shifted to CIO 010000.
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 Wd
Wd+1
Wd
Name Label Operation
Error Flag ER OFF
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.
Instruction executed once
Wd+1: CIO 0101 Wd: CIO 0100
Wd
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