334
Binary Calculation Instructions
Section 5-22
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:
ON when the result is negative, i.e., when Mi is less than Su plus CY.
EQ:
ON when the result is 0.
OF:
ON when the result e2,147,483,647 (7FFF FFFF).
UF:
ON when the result is below –2,147,483,648 (8000 0000).
Example
The following example shows an eight-digit subtraction with CY (SR 25504)
used to indicate a negative result (with unsigned data). The status of the UF
and OF flags indicate whether the result has exceeded the signed binary data
range (–2,147,483,648 (8000 0000) to +2,147,483,647 (7FFF FFFF)).
Note
1.
For unsigned binary data, CY indicates that the result is negative. Take the
2’s complement using NEGL(––) to obtain the absolute value of the true
result. (UF and OF can be ignored.)
2.
For signed binary data, the OF flag indicates that the result exceeds
+2,147,483,647 (7FFF FFFF). (CY can be ignored.)
5-22-7 SIGNED BINARY MULTIPLY – MBS(––)
Limitations
DM 6143 to DM 6655 cannot be used for R.
CLC(41)
00101
SBBL(
−−
)
LR 02
DM 0012
DM 0022
Address Instruction
Operands
00000
LD
00101
00001
CLC(41)
00002
SBBL(
−−
)
LR
22
DM
0012
DM
0022
Mi + 1 : LR 03
Mi : LR 02
Su + 1 : DM 0023
Su : DM 0022
F
F
F
F
F
F
F
0
0
R + 1 : LR 03
R : LR 02
0
CY (Cleared with CLC(41))
UF (SR 25405)
1
OF (SR 25404)
1
CY
F
F
F
0
7
F
F
F
8
0
0
0
0
0
0
0
Md
:
Multiplicand word
IR, SR, AR, DM, EM, HR, TIM/CNT, LR, #
Mr
:
Multiplier word
IR, SR, AR, DM, EM, HR, TIM/CNT, LR, #
Ladder Symbols
Operand Data Areas
R
:
First result word
IR, SR, AR, DM, EM, HR, LR
MBS(
−−
)
Md
Mr
R
@MBS(
−−
)
Md
Mr
R
