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Shift Instructions Section 5-17
5-17-3 ARITHMETIC SHIFT LEFT – ASL(25)
Limitations DM 6144 to DM 6655 cannot be used for Wd.
Description When the execution condition is OFF, ASL(25) is not executed. When the exe-
cution condition is ON, ASL(25) shifts a 0 into bit 00 of Wd, shifts the bits of
Wd one bit to the left, and shifts the status of bit 15 into CY.
Precautions A 0 will be shifted into bit 00 every cycle if the undifferentiated form of ASL(25)
is used. Use the differentiated form (@ASL(25)) or combine ASL(25) with
DIFU(13) or DIFD(14) to shift just one time.
Flags ER: Indirectly addressed EM/DM word is non-existent.
(Content of *EM/*DM word is not BCD, or the EM/DM area boundary
has been exceeded.)
CY: Receives the status of bit 15.
EQ: ON when the content of Wd is zero; otherwise OFF.
5-17-4 ARITHMETIC SHIFT RIGHT – ASR(26)
Limitations DM 6144 to DM 6655 cannot be used for Wd.
Description When the execution condition is OFF, ASR(25) is not executed. When the exe-
cution condition is ON, ASR(25) shifts a 0 into bit 15 of Wd, shifts the bits of
Wd one bit to the right, and shifts the status of bit 00 into CY.
Precautions A 0 will be shifted into bit 15 every cycle if the undifferentiated form of
ASR(26) is used. Use the differentiated form (@ASR(26)) or combine
ASR(26) with DIFU(13) or DIFD(14) to shift just one time.
Flags ER :Indirectly addressed EM/DM word is non-existent.
(Content of *EM/*DM word is not BCD, or the EM/DM area boundary
has been exceeded.)
Wd: Shift word
IR, SR, AR, DM, EM, HR, LR
Ladder Symbols Operand Data Areas
ASL(25)
Wd
@ASL(25)
Wd
1 0 0 1 1 1 0 0 0 1 0 1 0 0 1 1
Bit
00
Bit
15
0
CY
Wd: Shift word
IR, SR, AR, DM, EM, HR, LR
Ladder Symbols Operand Data Areas
ASR(26)
Wd
@ASR(26)
Wd
1 0 0 1 0 1 1 0 0 1 1 0 0 1 01
Bit
00
Bit
15
CY
0
0
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