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Symbol Math Instructions
Section 3-11
Flags
Precautions
If Mi, Mi +1 and/or Su, Su +1 are not BCD, an error is generated and the Error
Flag will turn ON.
If as a result of the subtraction, the content of R, R +1 is 00000000 hex, the
Equals Flag will turn ON.
If an subtraction results in a borrow, the Carry Flag will turn ON.
Note
To clear the Carry Flag (CY), execute the Clear Carry (CLC(041)) instruction.
Examples
When CIO 000000 is ON in the following example, D00111, D00110, and CY
will be subtracted from D00101 and D00100 as 8-digit BCD values, and the
result will be output to D00121 and D00120.
If the result of the subtraction is a negative number (Mi<Su or Mi+1, Mi
<Su+1, Su), the result is output as a 10’s complement. The Carry Flag (CY)
will turn ON. To convert the 10’s complement to the true number, a program
which subtracts the result from 0 is necessary, as an input condition of the
Carry Flag (CY). The Carry Flag turning ON thus indicates that the result of
the subtraction is negative.
Note 10’s Complement
A 10’s complement is the value obtained by subtracting each digit from 9 and
adding one to the result. For example, the 10’s complement for 7556 is calcu-
lated as follows: 9999 – 7556 + 1 = 2444. For a four digit number, the 10’s
complement of A is 9999 – A + 1 = B. To obtain the true number from the 10’s
complement B: A = 10000 – B. For example, to obtain the true number from
the 10’s complement 2444: 10000 – 2444 = 7556.
3-11-17 SIGNED BINARY MULTIPLY: *(420)
Purpose
Multiplies 4-digit signed hexadecimal data and/or constants.
Ladder Symbol
Name
Label
Operation
Error Flag
ER
ON when Mi and/or Mi +1 are not BCD.
ON when Su and/or Su +1 are not BCD.
OFF in all other cases.
Equals Flag
=
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.
*(420)
R
Md
Mr
Md
: Multiplicand word
Mr
: Multiplier word
R
: Result word
Содержание SYSMAC CS1D-CPU**
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Страница 185: ...146 List of Instructions by Function Code Section 2 4...
Страница 193: ...154 3 35 4 MOVE BIT MOVBC 568 1274 3 35 5 BIT COUNTER BCNTC 621 1276 3 35 6 GET VARIABLE ID GETID 286 1278...
Страница 1389: ...1350 CJ series Instruction Execution Times and Number of Steps Section 4 2...
Страница 1390: ...1351 Appendix A ASCII Code Table ASCII SP Four leftmost bits Four rightmost bits...
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