Flags function, Precautions, 2 instructions – Omron SYSMAC CP CP1E-N@@D@-@ User Manual
Page 178: Nasl, Nsll
2 Instructions
2-142
CP1E CPU Unit Instructions Reference Manual(W483)
Flags
Function
NASL
NASL(580) shifts D (the shift word) by the specified number of binary bits (specified in C) to the left
(from the rightmost bit to the leftmost bit). Either zeros or the value of the rightmost bit will be placed
into the specified number of bits of the shift word starting from the rightmost bit.
NSLL
NSLL(582) shifts D and D+1 (the shift words) by the specified number of binary bits (specified in C) to
the left (from the rightmost bit to the leftmost bit). Either zeros or the value of the rightmost bit will be
placed into the specified number of bits of the shift word starting from the rightmost bit.
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.
Name
Label
Operation
Error Flag
P_ER
• ON when the control word C (the number of bits to shift) is not within range.
• OFF in all other cases.
Equals Flag
P_EQ
• ON when the shift result is 0.
• OFF in all other cases.
Carry Flag
P_CY
• ON when 1 is shifted into the Carry Flag (CY).
• OFF in all other cases.
Negative Flag
P_N
• ON when the leftmost bit is 1 as a result of the shift.
• OFF in all other cases.
C
0
8
11
12
15
0
3
4
7
D
a
a
D
CY
Shift n-bits
Contents of “a” or “0” shifted in
N bits
Lost
C
0
8
11
12
15
0
3
4
7
D+1
D
CY
a
a
Shift n-bits
Contents of “a”
or “0” shifted in
N bits
Lost