Omron CJ - INSTRUCTIONS User Manual

363
3. Instructions
CS/CJ/NSJ Series Instructions Reference Manual (W474)
Symbol Math Instructions
3
–C/–CL
Flags
Function
z –C
–C(412) subtracts the binary values in Su and CY from Mi, and outputs the result to R. When the result
is negative, it is output to R as a 2's complement.
z –CL
–CL(413) subtracts the binary values in Su and Su+1 and CY from Mi and Mi+1, and outputs the result
to R, R+1. When the result is negative, it is output to R, R+1 as a 2's complement.
Hint
• To clear the Carry Flag (CY), execute the Clear Carry (CLC(041)) instruction.
• 2's Complement
A 2's complement is the value obtained by subtracting each binary digit from 1 and adding one to the
result.
Example: The 2's complement for the binary number 1101 is as follows:
1111 (F hex) – 1101 (D hex) + 1 (1 hex) = 0011 (3 hex).
Example: The 2's complement for the 4-digit hexadecimal number 3039 is as follows:
FFFF hex - 3039 hex + 0001 hex = CFC7 hex.
Accordingly, the 2's complement for the 4-digit hexadecimal value “a” is as follows:
FFFF hex – a hex + 0001 hex = b hex.
And to obtain the true number “a” hex from the 2's complement “b” hex:
a hex + 10000 hex – b hex.
Example: To obtain the true number from the 2's complement CFC& hex:
10000 hex – CFC7 hex = 3039 hex.
Name Label
Operation
–C –CL
Error Flag ER OFF OFF
Equals Flag = • ON when the subtraction result is 0.
• OFF in all other cases.
• ON when the result is 0.
• OFF in all other cases.
Carry Flag CY • ON when the subtraction results in a borrow.
• OFF in all other cases.
• ON when the results in a borrow.
• OFF in all other cases.
Overflow Flag OF • ON when the result of subtracting a negative num-
ber and CY from a positive number is in the range
8000 to FFFF hex.
• OFF in all other cases.
• ON when the result of subtracting a negative num-
ber and CY from a positive number is in the range
80000000 to FFFFFFFF hex.
• OFF in all other cases.
Underflow Flag UF • ON when the result of subtracting a positive num-
ber and CY from a negative number is in the
range 0000 to 7FFF hex.
• OFF in all other cases.
• ON when the result of subtracting a positive num-
ber and CY from a negative number is in the
range 00000000 to 7FFFFFFF hex.
• OFF in all other cases.
Negative Flag N • ON when the leftmost bit of the result is 1.
• OFF in all other cases.
• ON when the leftmost bit of the result is 1.
• OFF in all other cases.
–
CY
R
CY
Mi
Su
(Signed binary)
(Signed binary)
(Signed binary)
CY will turn ON
when there is a
borrow.
–
R+1
CY
R
CY
Mi+1
Su+1
Mi
Su
(Signed binary)
(Signed binary)
(Signed binary)
CY will turn ON
when there is a
borrow.

Omron CJ - INSTRUCTIONS Specifications

General

Brand	Omron
Model	CJ - INSTRUCTIONS
Category	Controller
Language	English