2-239

2 Instructions
CP1E CPU Unit Instructions Reference Manual(W483)
Floating-point Math
Instructions
2
+F, –F, *F, /F
*F/F

•If the absolute value of the result is greater than the maximum value that can be expressed as float-

ing-point data, the Overflow Flag will turn ON and the result will be output as ±∞.

•If the absolute value of the result is less than the minimum value that can be expressed as floating-

point data, the Underflow Flag will turn ON and the result will be output as 0.

Operation rules

The result of an operation is output as shown below depending on the combination of floating-point

data.

FLOATING-POINT ADD (+F)

Note 1 The results could be zero (including underflows), a numeral, +∞, or –∞.

ER The Error Flag will be turned ON and the instruction will not be executed.

FLOATING-POINT SUBTRACT (–F)

Note 1 The results could be zero (including underflows), a numeral, +∞, or –∞.

ER The Error Flag will be turned ON and the instruction will not be executed.

Augend
Addend 0Numeral +∞–∞NaN
00 Numeral +∞–∞
Numeral Numeral See note 1. +∞–∞
+∞+∞+∞+∞ER
–∞–∞–∞ER –∞
NaN ER
Minuend
Subtrahend 0Numeral +∞–∞NaN
00 Numeral +∞–∞
Numeral Numeral See note 1. +∞–∞
+∞–∞–∞ER –∞
–∞+∞+∞+∞ER
NaN ER
R+1 R
Md Multiplicand (floating-point data, 32 bits)
Md+1
Mr Multiplier (floating-point data, 32 bits)
Mr+1
Result (floating-point data, 32 bits)
×
R+1 R
÷
Dd Dividend (floating-point data, 32 bits)
Dd+1
Dr Divisor (floating-point data, 32 bits)
Dr+1
Result (floating-point data, 32 bits)