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Chapter 5 Instruction Specifications
5-49
Item number Arithmetic instructions-4 Name Binary subtraction (BINARY SUBTRACTION)
Ladder format Condition code
Processing time (µs)
Remark
R7F4 R7F3 R7F2 R7F1 R7F0
Average Maximum
d = s1 – s2 DER ERR SD V C Upper case: W
zzz
↕↕
41
Lower case: DW
Instruction format Number of steps
Condition Steps
d = s1 – s2 Word 4 58
Double word 6
Bit Word Double word
Usable I/O
XY
R,
M
TD, SS,
CU, CT WX WY
WR,
WM TC DX DY
DR,
DM
Constant
Other
d Substitution destination {{{ {{
s1 Minuend {{{{{{{{
s2 Subtrahend
{{{{{{{{
Function
• Subtracts s2 from s1 as the binary data, and substitutes the result into d as the binary data.
• The C flag is set to “1” if there is a digit decrease, and “0” if not.
C = s1m
x
s2m + s1m
x
dm + s2m
x
dm
• The V flag is set to “1” if the operation result is a meaningless signed-binary data, and “0” if it has meaning.
s1 s2 d V
Positive Positive Positive/Negative 0
Negative Negative Positive/Negative 0
Positive Negative Positive 0
Positive Negative Negative 1
Negative Positive Positive 1
Negative Positive Negative 0
s1
d
0
0
0
s2m
dm
C
−
Most significant bit
s2
s1m
V = s1m x s2m x dm + s1m x s2m x dm
Notes
• The combinations of d, s1 and s2 are as follows:
ds1s2
Word Word Word
Double word Double word Double word
Program example
X00000
WR0002 = WR0000 - WR0001
LD X00000
[
WR0002 = WR0000 - WR0001
]
Program description
• When input X00000 is on, the difference between WR0000 value and WR0001 value is substituted into WR0002.
d = s1 – s2