Mitsubishi Q02CPU

3
- 79
3.9 Numeric Values which can be Used in Sequence Programs
3.9.4 Real numbers (floating decimal point data)
3
SEQUENCE PROGRAM CONFIGURATION AND
EXECUTION CONDITIONS
3.9.4 Real numbers (floating decimal point data)
(1) Real numbers
Real numbers are single precision floating decimal point data.
(2) Internal expression of floating decimal point data
The CPU module internal expression of received real number data is explained below.
Real number data is expressed as shown below, using 2 word devices.
[Sign] 1.[Mantissa] 2
(exponent part)
The bit configuration used for internal expression of floating decimal point data is
shown and explained below.
(a) Sign
The sign is expressed at b31 as follows.
0: Positive
1: Negative
(b) Exponent part
The "n" of "2
n
" is expressed in various ways at b30 to b23, depending on the b30
to b23 BIN value.
(c) Mantissa:
For a binary value of 1.XXXXXX..., the "XXXXXX" portion of the value is
expressed at b22 to b0 (23 bits).
Diagram 3.67 Bit configuration of real number data
Diagram 3.68 Values stored in exponent part and exponents
b31 b30
to
b23 b22
to
b16 b15
to
b0
b31
b22 to b0
Mantissa (23bit)
b23 to b30
Exponent part (8bit)
Sign
b30 to b23
n
FFH
Not used
FEH
127
FDH
126
00H
Not used
02H
-125
01
H
-126
81H
2
80
H
1
7FH
0
7E
H
-1