Omron CJ - REFERENCE MANUAL 02-2010 Reference Manual page 552

3. Instructions
(2) Overflows, Underflows, and Illegal Calculations
• Overflows will be output as either positive or negative infinity, depending on the sign of the
result. Underflows will be output as either positive or negative zero, depending on the sign of
the result.
• Illegal calculations will result in NaN. Illegal calculations include adding infinity to a number
with the opposite sign, subtracting infinity from a number with the opposite sign, multiplying
zero and infinity, dividing zero by zero, or dividing infinity by infinity.
• The value of the result may not be correct if an overflow occurs when converting a floating-
point number to an integer.
(3) Precautions in Handling Special Values
The following precautions apply to handling zero, infinity, and NaN.
• The sum of positive zero and negative zero is positive zero.
• The difference between zeros of the same sign is positive zero.
• If any operand is a NaN, the results will be a NaN.
• Positive zero and negative zero are treated as equivalent in comparisons.
• Comparison or equivalency tests on one or more NaN will always be true for < > and always
be false for all other instructions.
Double-precision Floating-point Calculation Results
• When the absolute value of the result is greater than the maximum value that can be expressed
for floating-point data, the Overflow Flag will turn ON and the result will be output as
result is positive, it will be output as + ; if negative, then - .
• The Equals Flag will only turn ON when both the exponent (e) and the mantissa (f) are zero after
a calculation. A calculation result will also be output as zero when the absolute value of the result
is less than the minimum value that can be expressed for floating-point data. In that case the
Underflow Flag will turn ON.
Comparing Single-precision and Double-precision Calculations
This example shows the differences in between single-precision and double-precision calculations
when the following vector expressed in polar coordinates is converted to rectangular coordinates A
(x,y).
r = re j 360
In this example, the 4-digit BCD angle ( , in degrees) is read from D0 and the 4-digit BCD distance (r) is
read from D1000.
Y
r
0
516
A (x, y) = A (rcos , rsin )
r
X
CS/CJ/NSJ Series Instructions Reference Manual (W474)
. If the