2 instructions, Floating-point calculation results – Omron SYSMAC CP CP1E-N@@D@-@ User Manual

Page 268

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2 Instructions

2-232

CP1E CPU Unit Instructions Reference Manual(W483)

(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 Error Flag will be turned ON and the tests will not be executed.

• Positive zero and negative zero are treated as equivalent in comparisons.

• Comparison or equivalency tests on one or more NaN will not be executed and the Error Flag will be

turned ON.

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

±∞. If the result is pos-

itive, 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 cal-
culation. 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.

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